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1.  Access to weight reduction interventions for overweight and obese patients in UK primary care: population-based cohort study 
BMJ Open  2015;5(1):e006642.
Objectives
To investigate access to weight management interventions for overweight and obese patients in primary care.
Setting
UK primary care electronic health records.
Participants
A cohort of 91 413 overweight and obese patients aged 30–100 years was sampled from the Clinical Practice Research Datalink (CPRD). Patients with body mass index (BMI) values ≥25 kg/m2 recorded between 2005 and 2012 were included. BMI values were categorised using WHO criteria.
Interventions
Interventions for body weight management, including advice, referrals and prescription of antiobesity drugs, were evaluated.
Primary and secondary outcome measures
The rate of body weight management interventions and time to intervention were the main outcomes.
Results
Data were analysed for 91 413 patients, mean age 56 years, including 55 094 (60%) overweight and 36 319 (40%) obese, including 4099 (5%) with morbid obesity. During the study period, 90% of overweight patients had no weight management intervention recorded. Intervention was more frequent among obese patients, but 59% of patients with morbid obesity had no intervention recorded. Rates of intervention increased with BMI category. In morbid obesity, rates of intervention per 1000 patient years were: advice, 60.2 (95% CI 51.8 to 70.4); referral, 75.7 (95% CI 69.5 to 82.6) and antiobesity drugs 89.9 (95% CI 85.0 to 95.2). Weight management interventions were more often accessed by women, older patients, those with comorbidity and those in deprivation. Follow-up of body weight subsequent to interventions was infrequent.
Conclusions
Limited evidence of weight management interventions in primary care electronic health records may result from poor recording of advice given, but may indicate a lack of patient access to appropriate body weight management interventions in primary care.
doi:10.1136/bmjopen-2014-006642
PMCID: PMC4316417  PMID: 25586371
PRIMARY CARE; PUBLIC HEALTH; EPIDEMIOLOGY
2.  Continued high rates of antibiotic prescribing to adults with respiratory tract infection: survey of 568 UK general practices 
BMJ Open  2014;4(10):e006245.
Objectives
Overutilisation of antibiotics may contribute to the emergence of antimicrobial drug resistance, a growing international concern. This study aimed to analyse the performance of UK general practices with respect to antibiotic prescribing for respiratory tract infections (RTIs) among young and middle-aged adults.
Setting
Data are reported for 568 UK general practices contributing to the Clinical Practice Research Datalink.
Participants
Participants were adults aged 18–59 years. Consultations were identified for acute upper RTIs including colds, cough, otitis-media, rhino-sinusitis and sore throat.
Primary and secondary outcome measures
For each consultation, we identified whether an antibiotic was prescribed. The proportion of RTI consultations with antibiotics prescribed was estimated.
Results
There were 568 general practices analysed. The median general practice prescribed antibiotics at 54% of RTI consultations. At the highest prescribing 10% of practices, antibiotics were prescribed at 69% of RTI consultations. At the lowest prescribing 10% of practices, antibiotics were prescribed at 39% RTI consultations. The median practice prescribed antibiotics at 38% of consultations for ‘colds and upper RTIs’, 48% for ‘cough and bronchitis’, 60% for ‘sore throat’, 60% for ‘otitis-media’ and 91% for ‘rhino-sinusitis’. The highest prescribing 10% of practices issued antibiotic prescriptions at 72% of consultations for ‘colds’, 67% for ‘cough’, 78% for ‘sore throat’, 90% for ‘otitis-media’ and 100% for ‘rhino-sinusitis’.
Conclusions
Most UK general practices prescribe antibiotics to young and middle-aged adults with respiratory infections at rates that are considerably in excess of what is clinically justified. This will fuel antibiotic resistance.
doi:10.1136/bmjopen-2014-006245
PMCID: PMC4212213  PMID: 25348424
PUBLIC HEALTH
3.  Effectiveness of behavioural weight loss interventions delivered in a primary care setting: a systematic review and meta-analysis 
Family Practice  2014;31(6):643-653.
Background.
Overweight and obesity have negative health effects. Primary care clinicians are best placed to intervene in weight management. Previous reviews of weight loss interventions have included studies from specialist settings. The aim of this review was to estimate the effect of behavioural interventions delivered in primary care on body weight in overweight and obese adults.
Methods.
The review included randomized controlled trials (RCTs) of behavioural interventions in obese or overweight adult participants in a primary care setting, with weight loss as the primary outcome, and a minimum of 12 months of follow-up. A systematic search strategy was implemented in Medline, Embase, Web of Science and the Cochrane Central Registry of Controlled Trials. Risk of bias was assessed using the Cochrane Risk of Bias tool and behavioural science components of interventions were evaluated. Data relating to weight loss in kilograms were extracted, and the results combined using meta-analysis.
Results.
Fifteen RCTs, with 4539 participants randomized, were selected for inclusion. The studies were heterogeneous with respect to inclusion criteria and type of intervention. Few studies reported interventions informed by behavioural science theory. Pooled results from meta-analysis indicated a mean weight loss of −1.36kg (−2.10 to −0.63, P < 0.0001) at 12 months, and −1.23kg (−2.28 to −0.18, P = 0.002) at 24 months.
Conclusion.
Behavioural weight loss interventions in primary care yield very small reductions in body weight, which are unlikely to be clinically significant. More effective management strategies are needed for the treatment of overweight and obesity.
doi:10.1093/fampra/cmu064
PMCID: PMC4240316  PMID: 25298510
General practice; obesity; overweight; primary health care.
4.  Changes in Detection of Retinopathy in Type 2 Diabetes in the First 4 Years of a Population-Based Diabetic Eye Screening Program 
Diabetes Care  2013;36(9):2663-2669.
OBJECTIVE
Annual diabetic eye screening has been implemented in England since 2008. This study aimed to estimate changes in the detection of retinopathy in the first 4 years of the program.
RESEARCH DESIGN AND METHODS
Participants included 32,340 patients with type 2 diabetes resident in three London boroughs with one or more screening records between 2008 and 2011. Data for 87,570 digital images from 2008 to 2011 were analyzed. Frequency of sight-threatening diabetic retinopathy (STDR) was estimated by year of screen for first screens and for subsequent screens according to retinopathy status at first screen.
RESULTS
Among 16,621 first-ever screens, the frequency of STDR was 7.1% in 2008, declining to 6.4% in 2011 (P = 0.087). The proportion with a duration of diabetes of <1 year at first screen increased from 18.7% in 2008 to 48.6% in 2011. Second or later screens were received by 26,308 participants. In participants with mild nonproliferative retinopathy at first screen, the proportion with STDR at second or later screen declined from 21.6% in 2008 to 8.4% in 2011 (annual change −2.2% [95% CI −3.3 to −1.0], P < 0.001). In participants with no retinopathy at first screen, STDR declined from 9.2% in 2008 to 3.2% in 2011 (annual change −1.8% [−2.0 to −1.7], P < 0.001). Declining trends were similar in sociodemographic subgroups.
CONCLUSIONS
After the inception of population-based diabetic eye screening, patients at lower risk of STDR contribute an increasing proportion to the eligible population, and the proportion detected with STDR at second or subsequent screening rounds declines rapidly.
doi:10.2337/dc13-0130
PMCID: PMC3747895  PMID: 23620476
5.  Enhanced invitation methods to increase uptake of NHS health checks: study protocol for a randomized controlled trial 
Trials  2014;15(1):342.
Background
NHS Health Checks is a new program for primary prevention of heart disease, stroke, diabetes, chronic kidney disease, and vascular dementia in adults aged 40 to 74 years in England. Individuals without existing cardiovascular disease or diabetes are invited for a Health Check every 5 years. Uptake among those invited is lower than anticipated.
Method
The project is a three-arm randomized controlled trial to test the hypothesis that enhanced invitation methods, using the Question-Behaviour Effect (QBE), will increase uptake of NHS Health Checks compared with a standard invitation. Participants comprise individuals eligible for an NHS Health Check registered in two London boroughs. Participants are randomized into one of three arms. Group A receives the standard NHS Health Check invitation letter, information sheet, and reminder letter at 12 weeks for nonattenders. Group B receives a QBE questionnaire 1 week before receiving the standard invitation, information sheet, and reminder letter where appropriate. Group C is the same as Group B, but participants are offered a £5 retail voucher if they return the questionnaire. Participants are randomized in equal proportions, stratified by general practice. The primary outcome is uptake of NHS Health Checks 6 months after invitation from electronic health records. We will estimate the incremental health service cost per additional completed Health Check for trial groups B and C versus trial arm A, as well as evaluating the impact of the QBE questionnaire, and questionnaire plus voucher, on the socioeconomic inequality in uptake of Health Checks.
The trial includes a nested comparison of two methods for implementing allocation, one implemented manually at general practices and the other implemented automatically through the information systems used to generate invitations for the Health Check.
Discussion
The research will provide evidence on whether asking individuals to complete a preliminary questionnaire, by using the QBE, is effective in increasing uptake of Health Checks and whether an incentive alters questionnaire return rates as well as uptake of Health Checks. The trial interventions can be readily translated into routine service delivery if they are shown to be cost-effective.
Trial registration
Current Controlled Trials ISRCTN42856343. Date registered: 21.03.2013.
doi:10.1186/1745-6215-15-342
PMCID: PMC4156615  PMID: 25174568
Cardiovascular diseases; Risk assessment; Question-behavior effect; Behavioral medicine; Delivery of health care; NHS health check
6.  Cluster randomized trials utilizing primary care electronic health records: methodological issues in design, conduct, and analysis (eCRT Study) 
Trials  2014;15:220.
Background
There is growing interest in conducting clinical and cluster randomized trials through electronic health records. This paper reports on the methodological issues identified during the implementation of two cluster randomized trials using the electronic health records of the Clinical Practice Research Datalink (CPRD).
Methods
Two trials were completed in primary care: one aimed to reduce inappropriate antibiotic prescribing for acute respiratory infection; the other aimed to increase physician adherence with secondary prevention interventions after first stroke. The paper draws on documentary records and trial datasets to report on the methodological experience with respect to research ethics and research governance approval, general practice recruitment and allocation, sample size calculation and power, intervention implementation, and trial analysis.
Results
We obtained research governance approvals from more than 150 primary care organizations in England, Wales, and Scotland. There were 104 CPRD general practices recruited to the antibiotic trial and 106 to the stroke trial, with the target number of practices being recruited within six months. Interventions were installed into practice information systems remotely over the internet. The mean number of participants per practice was 5,588 in the antibiotic trial and 110 in the stroke trial, with the coefficient of variation of practice sizes being 0.53 and 0.56 respectively. Outcome measures showed substantial correlations between the 12 months before, and after intervention, with coefficients ranging from 0.42 for diastolic blood pressure to 0.91 for proportion of consultations with antibiotics prescribed, defining practice and participant eligibility for analysis requires careful consideration.
Conclusions
Cluster randomized trials may be performed efficiently in large samples from UK general practices using the electronic health records of a primary care database. The geographical dispersal of trial sites presents a difficulty for research governance approval and intervention implementation. Pretrial data analyses should inform trial design and analysis plans.
Trial registration
Current Controlled Trials ISRCTN 47558792 and ISRCTN 35701810 (both registered on 17 March 2010).
doi:10.1186/1745-6215-15-220
PMCID: PMC4062282  PMID: 24919485
Clinical trial; Cluster randomization; Electronic health records; Primary care; Implementation science; Decision support
7.  Cost-effectiveness of a universal strategy of brief dietary intervention for primary prevention in primary care: population-based cohort study and Markov model 
Background
A healthy diet is associated with reduced risk of diabetes, cardiovascular disease and cancer. The study aimed to evaluate the cost-effectiveness of a universal strategy to promote healthy diet through brief intervention in primary care.
Methods
The research was informed by a systematic review of randomised trials which found that brief interventions in primary care may be associated with a 0.5 portion per day increase in fruit and vegetable consumption. A Markov model that included five long-term conditions (diabetes, coronary heart disease, stroke, colorectal cancer and depression) was developed. Empirical data from a large cohort of United Kingdom-based participants sampled from the Clinical Practice Research Datalink populated the model. Simulations compared an intervention promoting healthy diet over 5 years in healthy adults, and standard care in which there was no intervention. The annual cost of intervention, in the base case, was one family practice consultation per participant year. Health service costs were included and the model adopted a lifetime perspective. The primary outcome was net health benefit in quality adjusted life years (QALYs).
Results
A cohort of 262,704 healthy participants entered the model. Intervention was associated with an increase in life years lived free from physical disease of 41.9 (95% confidence interval -17.4 to 101.0) per 1,000 participants entering the model (probability of increase 88.0%). New incidences of disease states were reduced by 28.4 (18.7 to 75.8) per 1,000, probability reduced 84.6%. Discounted incremental QALYs were 4.3 (-8.8 to 18.0) per 1,000, while incremental costs were £139,755 (£60,466 to 220,059) per 1,000. Net health benefits at £30,000 per QALY were -0.32 (-13.8 to 13.5) QALYs per 1,000 participants (probability cost-effective 47.9%). When the intervention was restricted to adults aged 50 to 74 years, net health benefits were 2.94 (-21.3 to 26.4) QALYs per 1000, probability increased 59.0%.
Conclusions
A universal strategy to promote healthy diet through brief intervention in primary care is unlikely to be cost-effective, even when delivered at low unit cost. A targeted strategy aimed at older individuals at higher risk of disease might be more cost-effective. More effective dietary change interventions are needed.
doi:10.1186/1478-7547-12-4
PMCID: PMC4015683  PMID: 24485221
Dietary intervention; Primary care; Markov model; Cost effectiveness; Outcomes; Diabetes; Coronary heart disease; Stroke; Colorectal cancer; Depression
8.  Effectiveness of interventions to promote healthy diet in primary care: systematic review and meta-analysis of randomised controlled trials 
BMC Public Health  2013;13:1203.
Background
A diet rich in fruit, vegetables and dietary fibre and low in fat is associated with reduced risk of chronic disease. This review aimed to estimate the effectiveness of interventions to promote healthy diet for primary prevention among participants attending primary care.
Methods
A systematic review of trials using individual or cluster randomisation of interventions delivered in primary care to promote dietary change over 12 months in healthy participants free from chronic disease or defined high risk states. Outcomes were change in fruit and vegetable intake, consumption of total fat and fibre and changes in serum cholesterol concentration.
Results
Ten studies were included with 12,414 participants. The design and delivery of interventions were diverse with respect to grounding in behavioural theory and intervention intensity. A meta-analysis of three studies showed an increase in fruit consumption of 0.25 (0.01 to 0.49) servings per day, with an increase in vegetable consumption of 0.25 (0.06 to 0.44) serving per day. A further three studies that reported on fruit and vegetable consumption together showed a pooled increment of 0.50 (0.13 to 0.87) servings per day. The pooled effect on consumption of dietary fibre, from four studies, was estimated to be 1.97 (0.43 to 3.52) gm fibre per day. Data from five studies showed a mean decrease in total fat intake of 5.2% of total energy (1.5 to 8.8%). Data from three studies showed a mean decrease in serum cholesterol of 0.10 (-0.19 to 0.00) mmol/L.
Conclusion
Presently-reported interventions to promote healthy diet for primary prevention in primary care, which illustrate a diverse range of intervention methods, may yield small beneficial changes in consumption of fruit, vegetables, fibre and fat over 12 months. The present results do not exclude the possibility that more effective intervention strategies might be developed.
doi:10.1186/1471-2458-13-1203
PMCID: PMC3890643  PMID: 24355095
Diet; Health promotion; Primary care; Systematic review; Meta-analysis
9.  Impact of body mass index on prevalence of multimorbidity in primary care: cohort study 
Family Practice  2013;31(1):38-43.
Background.
Multimorbidity is the co-occurrence of long-term conditions. Obesity is associated with an increased risk of long-term conditions including type 2 diabetes and depression.
Objective.
To quantify the association between body mass index (BMI) category and multimorbidity in a large cohort registered in primary care.
Methods.
The sample comprised primary care electronic health records of adults aged ≥30 years, sampled from the Clinical Practice Research Datalink between 2005 and 2011. Multimorbidity was defined as the co-occurrence of ≥2 of 11 conditions affecting seven organ systems. Age- and sex-standardized prevalence of multimorbidity was estimated by BMI category. Adjusted odds ratios associating BMI with additional morbidity were estimated adjusting for socioeconomic deprivation and smoking.
Results.
The sample comprised 300 006 adults. After excluding participants with BMI never recorded, data were analysed for 223 089 (74%) contributing 1 374 109 person–years. In normal weight men, the standardized prevalence of multimorbidity was 23%, rising to 27% in overweight, 33% in category I obesity, 38% in category II and 44% in category III obesity. In women, the corresponding values were 28%, 34%, 41%, 45% and 51%. In category III obesity, the adjusted odds, relative to normal BMI, were 2.24 (2.13–2.36) for a first condition; 2.63 (2.51–2.76) for a second condition and 3.09 (2.92–3.28) for three or more conditions. In a cross-sectional analysis, 32% of multimorbidity was attributable to overweight and obesity.
Conclusions.
Multiple morbidity is highly associated with increasing BMI category and obesity, highlighting the potential for targeted primary and secondary prevention interventions in primary care.
doi:10.1093/fampra/cmt061
PMCID: PMC3902211  PMID: 24132593
Cardiovascular diseases; comorbidity; diabetes mellitus; family practice; obesity; primary health care.
10.  Recent HbA1c Values and Mortality Risk in Type 2 Diabetes. Population-Based Case-Control Study 
PLoS ONE  2013;8(7):e68008.
This study aimed to evaluate mortality within 365 days of HbA1c values of <6.5% or >9.0% in participants with clinical type 2 diabetes mellitus. A matched nested case-control study was implemented, within a cohort of participants with type 2 diabetes from 2000 to 2008. Conditional logistic regression was used to model the odds ratio for mortality adjusting for comorbidity and drug utilisation. There were 97,450 participants with type 2 diabetes; 16,585 cases that died during follow up were matched to 16,585 controls. The most recent HbA1c value was <6.5% (48 mmol/mol) for 22.2% of cases and 24.2% of controls, the HbA1c was >9.0% for 9.0% of cases and 7.7% of controls. In a complete case analysis, the adjusted odds ratio (AOR) for mortality associated with most recent HbA1c <6.5% was 1.31 (95% confidence interval (CI): 1.21,1.42). After multiple imputation of missing HbA1c values the AOR was 1.20 (CI: 1.12,1.28). The complete case analysis gave an AOR for HbA1c >9.0% of 1.51 (CI: 1.33, 1.70), in the multiple imputation analysis this was 1.29 (1.17,1.41). The risk associated with HbA1c <6.5% was age dependent. In the multiple imputation analysis the AOR was 1.53 (CI: 0.84 to 2.79) at age<55 years but 1.04 (CI: 0.92, 1.17) at age 85 years and over. In non-randomised data, values of HbA1c that are either <6.5% or >9.0% may be associated with increased mortality within one year in clinical type 2 diabetes. Relative risks may be higher at younger ages.
doi:10.1371/journal.pone.0068008
PMCID: PMC3702542  PMID: 23861845
11.  Income, wealth and risk of diabetes among older adults: cohort study using the English longitudinal study of ageing 
Background: Socio-economic status has been associated with diabetes in cross-sectional studies. This study aimed to evaluate associations of household income and wealth with both prevalent and incident diabetes among older adults in the UK. It also evaluated the association between obesity and socio-economic status. Methods: A cohort of people aged ≥50 years was selected from the English Longitudinal Study of Ageing. The relation of prevalent and incident self-reported physician diagnosed diabetes to household income and wealth was evaluated in logistic regression models adjusting for education, social class, housing tenure, age, ethnicity, marital status, body mass index (BMI), smoking, alcohol use and physical activity stratified by sex. The relation of prevalent obesity to household income and wealth was also evaluated using logistic regression models. Results: There were 9053 participants (4021 men and 5032 women) including 721 (8.0%) with diabetes at baseline. Among 8332 participants initially free from diabetes, 246 (3.0%) were diagnosed with diabetes during ∼4 years follow-up. The adjusted odds ratio for prevalent diabetes in the lowest quintile of wealth compared with the highest was 1.56 for men and 2.08 for women. Incident diabetes was associated with lower wealth (P for trend 0.05 for men and 0.004 for women) after adjusting for socio-economic and demographic factors, but attenuated after further adjustment for lifestyle and BMI. Prevalent obesity was significantly associated with lower wealth in women but not in men. Conclusion: Lower wealth, but not income, may be associated with prevalent and incident diabetes among older adults in UK.
doi:10.1093/eurpub/ckr050
PMCID: PMC3530369  PMID: 21565937
12.  Impact and cost-effectiveness of a universal strategy to promote physical activity in primary care: population-based Cohort study and Markov model 
Background
This study aimed to estimate the cost-effectiveness of a universal strategy to promote physical activity in primary care.
Methods
Data were analysed for a cohort of participants from the general practice research database. Empirical estimates informed a Markov model that included five long-term conditions (diabetes, coronary heart disease, stroke, colorectal cancer and depression). Simulations compared an intervention promoting physical activity in healthy adults with standard care. The intervention effect on physical activity was from a meta-analysis of randomised trials. The annual cost of intervention, in the base case, was one family practice consultation per participant year. The primary outcome was net health benefit in quality adjusted life years (QALYs).
Results
A cohort of 262,704 healthy participants entered the model. Intervention was associated with an increase in life years lived free from physical disease. With 5 years intervention the increase was 52 (95 % interval −11 to 115) per 1,000 participants entering the model (probability increased 91.9 %); with 10 years intervention the increase was 102 (42–164) per 1,000 (probability 99.7 %). Net health benefits at a threshold of £30,000 per QALY were 3.2 (−11.1 to 16.9) QALYs per 1,000 participants with 5 years intervention (probability cost-effective 64.7 %) and 5.0 (−9.5 to 19.3) with 10 years intervention (probability cost-effective 72.4 %).
Conclusions
A universal strategy to promote physical activity in primary care has the potential to increase life years lived free from physical disease. There is only weak evidence that a universal intervention strategy might prove cost-effective.
doi:10.1007/s10198-013-0477-0
PMCID: PMC3996351  PMID: 23572044
Physical activity; Primary care; Markov model; Outcomes; Cost-effectiveness; Depression; Diabetes; Coronary heart disease; Stroke; Colorectal cancer; I10 Health; General; D61; Allocative efficiency
13.  Population Intermediate Outcomes of Diabetes Under Pay-for-Performance Incentives in England From 2004 to 2008  
Diabetes Care  2009;32(3):427-429.
OBJECTIVE—To evaluate diabetes outcomes under a national “pay-for-performance” program.
RESEARCH DESIGN AND METHODS—Data were analyzed for 98% of all English family practices. For each practice, the proportion of diabetic subjects with A1C ≤7.5%, blood pressure ≤145/85 mmHg, and cholesterol ≤5 mmol/l was determined. Practices achieving less than the 25th centile for the A1C target for 2006–2007 were classified as low performing.
RESULTS—The proportion achieving the A1C target at the median practice increased from 59.1% (interquartile range [IQR] 51.7–65.9) in 2004–2005 to 66.7% (IQR 60.6–72.7) in 2007–2008, blood pressure from 70.9% in 2004–2005 to 80.2% in 2007–2008, and cholesterol from 72.6% in 2004–2005 to 83.6% in 2007–2008. In 2004–2005, 57% of practices were low performing (range by region 42.4–69.9). In 2007–2008, 26% of practices were low performing (range 11.6–37.5).
CONCLUSIONS—Introduction of pay-for-performance may be one factor contributing to increasing achievement of targets and reducing problems of low performance.
doi:10.2337/dc08-1999
PMCID: PMC2646022  PMID: 19106379
14.  Ethnic Variation in the Prevalence of Visual Impairment in People Attending Diabetic Retinopathy Screening in the United Kingdom (DRIVE UK) 
PLoS ONE  2012;7(6):e39608.
Purpose
To provide estimates of visual impairment in people with diabetes attending screening in a multi-ethnic population in England (United Kingdom).
Methods
The Diabetic Retinopathy In Various Ethnic groups in UK (DRIVE UK) Study is a cross-sectional study on the ethnic variations of the prevalence of DR and visual impairment in two multi-racial cohorts in the UK. People on the diabetes register in West Yorkshire and South East London who were screened, treated or monitored between April 2008 to July 2009 (London) or August 2009 (West Yorkshire) were included in the study. Data on age, gender, ethnic group, visual acuity and diabetic retinopathy were collected. Ethnic group was defined according to the 2011 census classification. The two main ethnic minority groups represented here are Blacks (“Black/African/Caribbean/Black British”) and South Asians (“Asians originating from the Indian subcontinent”). We examined the prevalence of visual impairment in the better eye using three cut-off points (a) loss of vision sufficient for driving (approximately <6/9) (b) visual impairment (<6/12) and (c) severe visual impairment (<6/60), standardising the prevalence of visual impairment in the minority ethnic groups to the age-structure of the white population.
Results
Data on visual acuity and were available on 50,331individuals 3.4% of people diagnosed with diabetes and attending screening were visually impaired (95% confidence intervals (CI) 3.2% to 3.5%) and 0.39% severely visually impaired (0.33% to 0.44%). Blacks and South Asians had a higher prevalence of visual impairment (directly age standardised prevalence 4.6%, 95% CI 4.0% to 5.1% and 6.9%, 95% CI 5.8% to 8.0% respectively) compared to white people (3.3%, 95% CI 3.1% to 3.5%). Visual loss was also more prevalent with increasing age, type 1 diabetes and in people living in Yorkshire.
Conclusions
Visual impairment remains an important public health problem in people with diabetes, and is more prevalent in the minority ethnic groups in the UK.
doi:10.1371/journal.pone.0039608
PMCID: PMC3384630  PMID: 22761840
15.  Epilepsy mortality and risk factors for death in epilepsy: a population-based study 
The British Journal of General Practice  2011;61(586):e271-e278.
Background
Epilepsy is an important cause of amenable mortality but risk factors for death in epilepsy are not well understood.
Aim
To evaluate trends in epilepsy mortality in a large population and identify risk factors for death in epilepsy.
Design and setting
Nested case–control study in the UK, using data from the General Practice Research Database (GPRD) from 1993 to 2007.
Method
Participants were included if they had ever been diagnosed with epilepsy and prescribed anticonvulsant drugs. Trends in all-cause mortality in persons with epilepsy in the GPRD were compared with death registrations with epilepsy as the underlying cause. A nested case–control study was implemented to compare participants with epilepsy who died with those who did not die.
Results
The prevalence of epilepsy increased from 9 per 1000 in 1993 to 12 per 1000 in 2007, and epilepsy deaths also increased in this period. In a nested case–control study, mortality was associated with: recorded alcohol problems (odds ratio [OR] 2.96, 95% confidence interval [CI] = 2.25 to 3.89, P<0.001); having collected the last anticonvulsant prescription 90–182 days previously (OR 1.83, CI = 1.66 to 2.03, P<0.001); having an injury in the previous year (OR 1.41, 95% CI = 1.30 to 1.53, P<0.001), and having been treated for depression (OR 1.39, 95% CI = 1.28 to 1.50, P<0.001). In data available from 2004 onwards, being recorded seizure free in the previous 12 months was associated with lower mortality (OR 0.78, 95% CI = 0.71 to 0.86, P<0.001).
Conclusion
Mortality with epilepsy appears to be increasing. Patients who have alcohol problems, do not collect repeat prescriptions for anticonvulsant drugs, have recent injuries, or have been treated for depression may be at increased risk of death; patients who remain seizure free over 12 months are at a lower risk.
doi:10.3399/bjgp11X572463
PMCID: PMC3080232  PMID: 21619751
cohort study; epilepsy mortality; epilepsy prevalence; nested case-control study; primary care
16.  Ethnic Variations in the Prevalence of Diabetic Retinopathy in People with Diabetes Attending Screening in the United Kingdom (DRIVE UK) 
PLoS ONE  2012;7(3):e32182.
Aims
To compare the prevalence of diabetic retinopathy (DR) in people of various ethnic groups with diabetes in the United Kingdom (UK).
Methods
The Diabetic Retinopathy In Various Ethnic groups in UK (DRIVE UK) Study is a cross-sectional study on the ethnic variations of the prevalence of DR and visual impairment in two multi-racial cohorts in the UK. People on the diabetes register in West Yorkshire and South East London who were screened, treated or monitored between April 2008 to July 2009 (London) or August 2009 (West Yorkshire) were included in the study. Data included age, sex, ethnic group, type of diabetes, presenting visual acuity and the results of grading of diabetic retinopathy. Prevalence estimates for the ethnic groups were age-standardised to the white European population for comparison purposes.
Results
Out of 57,144 people on the two diabetic registers, data were available on 50,285 individuals (88.0%), of these 3,323 had type 1 and 46,962 had type 2 diabetes. In type 2 diabetes, the prevalence of any DR was 38.0% (95% confidence interval(CI) 37.4% to 38.5%) in white Europeans compared to 52.4% (51.2% to 53.6%) in African/Afro-Caribbeans and 42.3% (40.3% to 44.2%) in South Asians. Similarly, sight threatening DR was also significantly more prevalent in Afro-Caribbeans (11.5%, 95% CI 10.7% to 12.3%) and South Asians (10.3%, 9.0% to 11.5%) compared to white Europeans (5.5%, 5.3% to 5.8%). Differences observed in Type 1 diabetes did not achieve conventional levels of statistical significance, but there were lower numbers for these analyses.
Conclusions
Minority ethnic communities with type 2 diabetes in the UK are more prone to diabetic retinopathy, including sight-threatening retinopathy and maculopathy compared to white Europeans.
doi:10.1371/journal.pone.0032182
PMCID: PMC3297598  PMID: 22412857
17.  Coding, Recording and Incidence of Different Forms of Coronary Heart Disease in Primary Care 
PLoS ONE  2012;7(1):e29776.
Objectives
To evaluate the coding, recording and incidence of coronary heart disease (CHD) in primary care electronic medical records.
Methods
Data were drawn from the UK General Practice Research Database. Analyses evaluated the occurrence of 271 READ medical diagnostic codes, including categories for ‘Angina’, ‘Myocardial Infarction’, ‘Coronary Artery Bypass Grafting’ (CABG), ‘percutaneous transluminal coronary angioplasty’ (PCTA) and ‘Other Coronary Heart Disease’. Time-to-event analyses were implemented to evaluate occurrences of different groups of codes after the index date.
Results
Among 300,020 participants aged greater than 30 years there were 75,197 unique occurrences of coronary heart disease codes in 24,244 participants, with 12,495 codes for incident events and 62,702 for prevalent events. Among incident event codes, 3,607 (28.87%) were for angina, 3,262 (26.11%) were for MI, 514 (4.11%) for PCTA, 161 (1.29%) for CABG and 4,951 (39.62%) were for ‘Other CHD’. Among prevalent codes, 20,254 (32.30%) were for angina, 3,644 (5.81%) for MI, 34,542 (55.09%) for ‘Other CHD’ and 4,262 (6.80%) for CABG or PCTA. Among 3,685 participants initially diagnosed exclusively with ‘Other CHD’ codes, 17.1% were recorded with angina within 5 years, 5.6% with myocardial infarction, 6.3% with CABG and 8.6% with PCTA. From 2000 to 2010, the overall incidence of CHD declined, as did the incidence of angina, but the incidence of MI did not change. The frequency of CABG declined, while PCTA increased.
Conclusion
In primary care electronic records, a substantial proportion of coronary heart disease events are recorded with codes that do not distinguish between different clinical presentations of CHD. The results draw attention to the need to improve coding practice in primary care. The results also draw attention to the importance of code selection in research studies and the need for sensitivity analyses using different sets of codes.
doi:10.1371/journal.pone.0029776
PMCID: PMC3261876  PMID: 22276128
18.  Potential application of item-response theory to interpretation of medical codes in electronic patient records 
Background
Electronic patient records are generally coded using extensive sets of codes but the significance of the utilisation of individual codes may be unclear. Item response theory (IRT) models are used to characterise the psychometric properties of items included in tests and questionnaires. This study asked whether the properties of medical codes in electronic patient records may be characterised through the application of item response theory models.
Methods
Data were provided by a cohort of 47,845 participants from 414 family practices in the UK General Practice Research Database (GPRD) with a first stroke between 1997 and 2006. Each eligible stroke code, out of a set of 202 OXMIS and Read codes, was coded as either recorded or not recorded for each participant. A two parameter IRT model was fitted using marginal maximum likelihood estimation. Estimated parameters from the model were considered to characterise each code with respect to the latent trait of stroke diagnosis. The location parameter is referred to as a calibration parameter, while the slope parameter is referred to as a discrimination parameter.
Results
There were 79,874 stroke code occurrences available for analysis. Utilisation of codes varied between family practices with intraclass correlation coefficients of up to 0.25 for the most frequently used codes. IRT analyses were restricted to 110 Read codes. Calibration and discrimination parameters were estimated for 77 (70%) codes that were endorsed for 1,942 stroke patients. Parameters were not estimated for the remaining more frequently used codes. Discrimination parameter values ranged from 0.67 to 2.78, while calibration parameters values ranged from 4.47 to 11.58. The two parameter model gave a better fit to the data than either the one- or three-parameter models. However, high chi-square values for about a fifth of the stroke codes were suggestive of poor item fit.
Conclusion
The application of item response theory models to coded electronic patient records might potentially contribute to identifying medical codes that offer poor discrimination or low calibration. This might indicate the need for improved coding sets or a requirement for improved clinical coding practice. However, in this study estimates were only obtained for a small proportion of participants and there was some evidence of poor model fit. There was also evidence of variation in the utilisation of codes between family practices raising the possibility that, in practice, properties of codes may vary for different coders.
doi:10.1186/1471-2288-11-168
PMCID: PMC3261214  PMID: 22176509
19.  Cluster randomised trial in the General Practice Research Database: 1. Electronic decision support to reduce antibiotic prescribing in primary care (eCRT study) 
Trials  2011;12:115.
Background
The purpose of this research is to develop and evaluate methods for conducting cluster randomised trials in a primary care database that contains electronic patient records for large numbers of family practices. Cluster randomised trials are trials in which the units allocated represent groups of individuals, in this case family practices and their registered patients. Cluster randomised trials often suffer from the limitation that they include too few clusters, leading to problems of insufficient power and only imprecise estimation of the intraclass correlation coefficient, a key design parameter. This difficulty might be overcome by utilising databases that already hold electronic patient records for large numbers of practices. The protocol describes one application: a study of antibiotic prescribing for acute respiratory infection; a second protocol outlines an intervention in a less frequent chronic condition of public health importance, stroke.
Methods/Design
The objective of the study is to implement a cluster randomised trial to test the effectiveness of an electronic record-based intervention at achieving a reduction in antibiotic prescribing at consultations for respiratory illness in patients aged 18 and 59 years old in intervention family practices as compared with controls. Family practices will be recruited from the practices that presently contribute data to the UK General Practice Research Database (GPRD). Following randomisation, electronic prompts will be installed remotely at intervention practices to promote adherence with evidence-based standards of medical practice. The intervention was developed through qualitative research at non-intervention practices. Data for outcome assessment will be obtained from anonymised electronic patient records that are routinely collected into GPRD. This protocol outlines the proposed study designs, data sources, sample size requirements, analysis methods and dissemination plans. Ethical issues are also discussed.
Discussion
Results from this study will provide methodological evidence concerning the use of electronic patient records and databases for implementing cluster randomised trials in primary care. The study will also provide substantive findings in respect of electronic record-based interventions to reduce antibiotic prescribing in primary care.
Trial Registration
Current Controlled Trials ISRCTN 47558792.
doi:10.1186/1745-6215-12-115
PMCID: PMC3101122  PMID: 21569237
20.  Place of medical qualification and outcomes of UK General Medical Council “fitness to practise” process: cohort study 
Objectives To evaluate whether country of medical qualification is associated with “higher impact” decisions at different stages of the UK General Medical Council’s (GMC’s) “fitness to practise” process after allowing for other characteristics of doctors and inquiries.
Design Retrospective cohort study.
Setting Medical practice in the United Kingdom.
Participants 7526 inquiries to the GMC concerning 6954 doctors.
Main outcome measures Proportion of inquiries referred for further investigation at initial triage by the GMC, proportion of inquiries investigated that were subsequently referred for adjudication, and proportion of inquiries resulting in doctors being erased or suspended from the medical register; relative odds of higher impact decisions, by country of qualification, adjusted for doctors’ sex, years since primary medical qualification, medical specialty, source and type of inquiry, and nature of allegations.
Results Of 7526 inquiries, 4702 concerned doctors who qualified in the UK, 624 concerned doctors who qualified elsewhere in the European Union (EU), and 2190 concerned doctors who qualified outside the EU. At the initial triage, 30% (n=1398) of inquiries concerning doctors who qualified in the UK had a high impact decision, compared with 43% (267) for doctors who qualified elsewhere in the EU and 46% (998) for those who qualified outside the EU. The adjusted relative odds of an inquiry being referred for further investigation were 1.67 (95% confidence interval 1.28 to 2.17) for doctors who qualified elsewhere in the EU and 1.61 (1.38 to 1.88) for those who qualified outside the EU, compared with doctors who qualified in the UK. At the investigation stage, 5% (228) of inquiries received concerning UK qualified doctors were referred for adjudication, compared with 10% for EU (63) or non-EU (221) qualified doctors. The adjusted relative odds of referral for adjudication were 2.14 (1.46 to 3.16) for doctors who qualified elsewhere in the EU and 1.68 (1.31 to 2.16) for those who qualified outside the EU. At the adjudication stage, 1% (69) of inquiries received concerning UK qualified doctors led to erasure or suspension, compared with 4% (24) for doctors who qualified elsewhere in the EU and 3% (71) for non-EU qualified doctors. The adjusted relative odds of erasure or suspension were 2.16 (1.22 to 3.80) for doctors who qualified elsewhere in the EU and 1.48 (1.00 to 2.19) for those who qualified outside the EU.
Conclusions Inquiries to the GMC concerning doctors qualified outside the UK are more likely to be associated with higher impact decisions at each stage of the fitness to practice process. These associations were not explained by measured inquiry related and doctor related characteristics, but residual confounding cannot be excluded.
doi:10.1136/bmj.d1817
PMCID: PMC3071377  PMID: 21467101
21.  Utility of electronic patient records in primary care for stroke secondary prevention trials 
BMC Public Health  2011;11:86.
Background
This study aimed to inform the design of a pragmatic trial of stroke prevention in primary care by evaluating data recorded in electronic patient records (EPRs) as potential outcome measures. The study also evaluated achievement of recommended standards of care; variation between family practices; and changes in risk factor values from before to after stroke.
Methods
Data from the UK General Practice Research Database (GPRD) were analysed for 22,730 participants with an index first stroke between 2003 and 2006 from 414 family practices. For each subject, the EPR was evaluated for the 12 months before and after stroke. Measures relevant to stroke secondary prevention were analysed including blood pressure (BP), cholesterol, smoking, alcohol use, body mass index (BMI), atrial fibrillation, utilisation of antihypertensive, antiplatelet and cholesterol lowering drugs. Intraclass correlation coefficients (ICC) were estimated by family practice. Random effects models were fitted to evaluate changes in risk factor values over time.
Results
In the 12 months following stroke, BP was recorded for 90%, cholesterol for 70% and body mass index (BMI) for 47%. ICCs by family practice ranged from 0.02 for BP and BMI to 0.05 for LDL and HDL cholesterol. For subjects with records available both before and after stroke, the mean reductions from before to after stroke were: mean systolic BP, 6.02 mm Hg; diastolic BP, 2.78 mm Hg; total cholesterol, 0.60 mmol/l; BMI, 0.34 Kg/m2. There was an absolute reduction in smokers of 5% and heavy drinkers of 4%. The proportion of stroke patients within the recommended guidelines varied from less than a third (29%) for systolic BP, just over half for BMI (54%), and over 90% (92%) on alcohol consumption.
Conclusions
Electronic patient records have potential for evaluation of outcomes in pragmatic trials of stroke secondary prevention. Stroke prevention interventions in primary care remain suboptimal but important reductions in vascular risk factor values were observed following stroke. Better recording of lifestyle factors in the GPRD has the potential to expand the scope of the GPRD for health care research and practice.
doi:10.1186/1471-2458-11-86
PMCID: PMC3041663  PMID: 21299872
22.  Family Practices' Achievement of Diabetes Quality of Care Targets and Risk of Screen-Detected Diabetic Retinopathy 
PLoS ONE  2010;5(4):e10424.
Background
We aimed to determine whether family practices' achievement of diabetes quality of care targets is associated with diabetic retinal disease in registered patients.
Methods
Data for achievement of diabetes quality of care targets, including the proportion of patients with HbA1c≤7.5%, for 144 family practices in London UK, for the years 2004/5 to 2007/8, were linked to data from a population-based diabetes eye screening programme collected from September 2007 to February 2009. Analyses were adjusted for age, sex, duration and type of diabetes, unadjusted diabetes prevalence, ethnicity and deprivation category.
Results
Data were analysed for 24,458 participants with one or more eye screening results in the period. There were 9,332 (38%) with any diabetic retinopathy and 2,819 (11.5%) with sight threatening diabetic retinopathy (STDR), including 2,654 (10.9%) with maculopathy. Among participants registered at 13 family practices that were in the highest quartile for achievement of the HbA1c quality of care target for all four years of study, the relative odds of any diabetic retinopathy were 0.78 (0.69 to 0.88) P<0.001. For participants at 12 practices consistently in the lowest quartile of HbA1c achievement, the relative odds of any diabetic retinopathy were 1.16 (1.03 to 1.30), P = 0.015. In the highest achieving practices, the relative odds of maculopathy were 0.74 (0.62 to 0.89), P = 0.001 and STDR 0.77 (0.65 to 0.92), P = 0.004.
Conclusions
The risk of diabetic retinopathy might be lower at family practices that consistently achieve highly on diabetes quality of care targets for HbA1c.
doi:10.1371/journal.pone.0010424
PMCID: PMC2861682  PMID: 20454691
23.  Declining 1-year case-fatality of stroke and increasing coverage of vascular risk management: population-based cohort study 
Background
The authors estimated trends in 1-year case-fatality of stroke in relation to changes in vascular risk management from 1997 to 2005.
Methods
A cohort study was implemented using data for 407 family practices in the UK General Practice Research Database, including subjects with first acute strokes between 1997 and 2005. One-year case-fatality was estimated by year and sex. Rate ratios were estimated using Poisson regression.
Results
There were 19 143 women and 16 552 men who had first acute strokes between 1997 and 2005. In women, the 1-year case-fatality declined from 41.2% in 1997 to 29.2% in 2005. In men, the decline was from 29.2% in 1997 to 22.2% in 2005. The proportion of general practices that prescribed antihypertensive drugs to two-thirds or more of new patients with stroke increased from 6% in 1997 to 48% in 2005, for statins from 1% to 39% and for antiplatelet drugs from 11% to 39%. The rate ratio for 1-year mortality in 2005, compared with 1997–1998, adjusted for age group, sex, prevalent coronary heart disease, prevalent hypertension and deprivation quintile was 0.79 (0.74 to 0.86, p<0.001). After adjustment for antihypertensive, statin and antiplatelet prescribing, the rate ratio was 1.29 (1.17 to 1.42).
Conclusions
Reducing 1-year case-fatality after acute stroke may be partly explained by increased prescribing of antihypertensive, statin and antiplatelet drugs to patients with recent strokes. However, these analyses did not include measures of possible changes over time in stroke severity or acute stroke management.
doi:10.1136/jnnp.2009.193136
PMCID: PMC2921278  PMID: 20176596
Stroke; mortality; survival rate; primary healthcare; hypertension; Hydroxymethylglutaryl-CoA reductase inhibitors; platelet aggregation inhibitors
25.  Selection of Medical Diagnostic Codes for Analysis of Electronic Patient Records. Application to Stroke in a Primary Care Database 
PLoS ONE  2009;4(9):e7168.
Background
Electronic patient records from primary care databases are increasingly used in public health and health services research but methods used to identify cases with disease are not well described. This study aimed to evaluate the relevance of different codes for the identification of acute stroke in a primary care database, and to evaluate trends in the use of different codes over time.
Methods
Data were obtained from the General Practice Research Database from 1997 to 2006. All subjects had a minimum of 24 months of up-to-standard record before the first recorded stroke diagnosis. Initially, we identified stroke cases using a supplemented version of the set of codes for prevalent stroke used by the Office for National Statistics in Key health statistics from general practice 1998 (ONS codes). The ONS codes were then independently reviewed by four raters and a restricted set of 121 codes for ‘acute stroke’ was identified but the kappa statistic was low at 0.23.
Results
Initial extraction of data using the ONS codes gave 48,239 cases of stroke from 1997 to 2006. Application of the restricted set of codes reduced this to 39,424 cases. There were 2,288 cases whose index medical codes were for ‘stroke annual review’ and 3,112 for ‘stroke monitoring’. The frequency of stroke review and monitoring codes as index codes increased from 9 per year in 1997 to 1,612 in 2004, 1,530 in 2005 and 1,424 in 2006. The one year mortality of cases with the restricted set of codes was 29.1% but for ‘stroke annual review,’ 4.6% and for ‘stroke monitoring codes’, 5.7%.
Conclusion
In the analysis of electronic patient records, different medical codes for a single condition may have varying clinical and prognostic significance; utilisation of different medical codes may change over time; researchers with differing clinical or epidemiological experience may have differing interpretations of the relevance of particular codes. There is a need for greater transparency in the selection of sets of codes for different conditions, for the reporting of sensitivity analyses using different sets of codes, as well as sharing of code sets among researchers.
doi:10.1371/journal.pone.0007168
PMCID: PMC2744876  PMID: 19777060

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