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1.  The Alvarado score for predicting acute appendicitis: a systematic review 
BMC Medicine  2011;9:139.
The Alvarado score can be used to stratify patients with symptoms of suspected appendicitis; the validity of the score in certain patient groups and at different cut points is still unclear. The aim of this study was to assess the discrimination (diagnostic accuracy) and calibration performance of the Alvarado score.
A systematic search of validation studies in Medline, Embase, DARE and The Cochrane library was performed up to April 2011. We assessed the diagnostic accuracy of the score at the two cut-off points: score of 5 (1 to 4 vs. 5 to 10) and score of 7 (1 to 6 vs. 7 to 10). Calibration was analysed across low (1 to 4), intermediate (5 to 6) and high (7 to 10) risk strata. The analysis focused on three sub-groups: men, women and children.
Forty-two studies were included in the review. In terms of diagnostic accuracy, the cut-point of 5 was good at 'ruling out' admission for appendicitis (sensitivity 99% overall, 96% men, 99% woman, 99% children). At the cut-point of 7, recommended for 'ruling in' appendicitis and progression to surgery, the score performed poorly in each subgroup (specificity overall 81%, men 57%, woman 73%, children 76%). The Alvarado score is well calibrated in men across all risk strata (low RR 1.06, 95% CI 0.87 to 1.28; intermediate 1.09, 0.86 to 1.37 and high 1.02, 0.97 to 1.08). The score over-predicts the probability of appendicitis in children in the intermediate and high risk groups and in women across all risk strata.
The Alvarado score is a useful diagnostic 'rule out' score at a cut point of 5 for all patient groups. The score is well calibrated in men, inconsistent in children and over-predicts the probability of appendicitis in women across all strata of risk.
PMCID: PMC3299622  PMID: 22204638
2.  Validity of British Thoracic Society guidance (the CRB-65 rule) for predicting the severity of pneumonia in general practice: systematic review and meta-analysis 
The British Journal of General Practice  2010;60(579):e423-e433.
The CRB-65 score is a clinical prediction rule that grades the severity of community-acquired pneumonia in terms of 30-day mortality.
The study sought to validate CRB-65 and assess its clinical value in community and hospital settings.
Design of study
Systematic review and meta-analysis of validation studies of CRB-65.
Medline (1966 to June 2009), Embase (1988 to November 2008), British Nursing Index (BNI) and PsychINFO were searched, using a diagnostic accuracy search filter combined with subject-specific terms. The derived (index) rule was used as a predictive model and applied to all validation studies. Comparison was made between the observed and predicted number of deaths stratified by risk group (low, intermediate, and high) and setting of care (community or hospital). Pooled results are presented as risk ratios (RRs) in terms of over-prediction (RR>1) or under-prediction (RR<1) of 30-day mortality.
Fourteen validation studies totalling 397 875 patients are included. CRB-65 performs well in hospitalised patients, particularly in those classified as intermediate (RR 0.91, 95% confidence interval [CI] = 0.71 to 1.17) or high risk (RR 1.01, 95% CI = 0.87 to 1.16). In community settings, CRB-65 over-predicts the probability of 30-day mortality across all strata of predicted risk, low (RR 9.41, 95% CI = 1.75 to 50.66), intermediate (RR 4.84, 95% CI = 2.61 to 8.69), and high (RR 1.58, 95% CI = 0.59 to 4.19).
CRB-65 performs well in stratifying severity of pneumonia and resultant 30-day mortality in hospital settings. In community settings, CRB-65 appears to over-predict the probability of 30-day mortality across all strata of predicted risk. Caution is needed when applying CRB-65 to patients in general practice.
PMCID: PMC2944951  PMID: 20883616
general practice; meta-analysis; pneumonia; prognosis; severity of illness index
3.  Predicting streptococcal pharyngitis in adults in primary care: a systematic review of the diagnostic accuracy of symptoms and signs and validation of the Centor score 
BMC Medicine  2011;9:67.
Stratifying patients with a sore throat into the probability of having an underlying bacterial or viral cause may be helpful in targeting antibiotic treatment. We sought to assess the diagnostic accuracy of signs and symptoms and validate a clinical prediction rule (CPR), the Centor score, for predicting group A β-haemolytic streptococcal (GABHS) pharyngitis in adults (> 14 years of age) presenting with sore throat symptoms.
A systematic literature search was performed up to July 2010. Studies that assessed the diagnostic accuracy of signs and symptoms and/or validated the Centor score were included. For the analysis of the diagnostic accuracy of signs and symptoms and the Centor score, studies were combined using a bivariate random effects model, while for the calibration analysis of the Centor score, a random effects model was used.
A total of 21 studies incorporating 4,839 patients were included in the meta-analysis on diagnostic accuracy of signs and symptoms. The results were heterogeneous and suggest that individual signs and symptoms generate only small shifts in post-test probability (range positive likelihood ratio (+LR) 1.45-2.33, -LR 0.54-0.72). As a decision rule for considering antibiotic prescribing (score ≥ 3), the Centor score has reasonable specificity (0.82, 95% CI 0.72 to 0.88) and a post-test probability of 12% to 40% based on a prior prevalence of 5% to 20%. Pooled calibration shows no significant difference between the numbers of patients predicted and observed to have GABHS pharyngitis across strata of Centor score (0-1 risk ratio (RR) 0.72, 95% CI 0.49 to 1.06; 2-3 RR 0.93, 95% CI 0.73 to 1.17; 4 RR 1.14, 95% CI 0.95 to 1.37).
Individual signs and symptoms are not powerful enough to discriminate GABHS pharyngitis from other types of sore throat. The Centor score is a well calibrated CPR for estimating the probability of GABHS pharyngitis. The Centor score can enhance appropriate prescribing of antibiotics, but should be used with caution in low prevalence settings of GABHS pharyngitis such as primary care.
PMCID: PMC3127779  PMID: 21631919
4.  A Common Variant in MTHFD1L is Associated with Neural Tube Defects and mRNA Splicing Efficiency 
Human mutation  2009;30(12):1650-1656.
Polymorphisms in folate-related genes have emerged as important risk factors in a range of diseases including neural tube defects (NTDs), cancer and coronary artery disease (CAD). Having previously identified a polymorphism within the cytoplasmic folate enzyme, MTHFD1, as a maternal risk factor for NTDs; we considered the more recently identified mitochondrial paralogue, MTHFD1L as a candidate gene for NTD association. We identified a common deletion/insertion polymorphism, rs3832406, c.781-6823ATT(7-9), that influences splicing efficiency and is strongly associated with NTD risk. Three alleles of rs3832406 were detected in the Irish population with varying number of ATT repeats; Allele 1 consists of ATT7, while Alleles 2 and 3 consist of ATT8 and ATT9 respectively. Allele 2 of this triallelic polymorphism showed a decreased case risk as demonstrated by case-control logistic regression (P= 0.002) and by transmission disequilibrium test (TDT) (P= 0.001); while Allele 1 showed an increased case risk. Allele 3 showed no influence on NTD risk and represents the lowest frequency allele (0.15). Additional SNP genotyping in the same genomic region provides additional supportive evidence of an association. We demonstrate that two of the three alleles of rs3832406 are functionally different and influence the splicing efficiency of the alternate MTHFD1L mRNA transcripts.
PMCID: PMC2787683  PMID: 19777576
MTHFD1L; NTD; Splicing; Polymorphism; Association; Folate; Mitochondria
5.  Comparison of self-reported health & healthcare utilisation between asylum seekers and refugees: an observational study 
BMC Public Health  2009;9:214.
Adult refugees and asylum seekers living in Western countries experience a high prevalence of mental health problems, especially post traumatic stress disorder (PTSD), depression and anxiety. This study compares and contrasts the prevalence of health problems, and potential risk factors as well as the utilisation of health services by asylum seekers and refugees in the Irish context.
Cross sectional study using validated self reported health status questionnaires of adult asylum seekers (n = 60) and refugees (n = 28) from 30 countries, living in Ireland. Outcome measures included: general health status (SF-36), presence of PTSD symptoms and anxiety/depression symptoms. Data on chronic conditions and pre or post migration stressors are also reported. The two groups are compared for utilisation of the health care system and the use of over the counter medications.
Asylum seekers were significantly more likely than refugees to report symptoms of PTSD (OR 6.3, 95% CI: 2.2–17.9) and depression/anxiety (OR 5.8, 95% CI: 2.2–15.4), while no significant difference was found in self-reported general health. When adjusted by multivariable regression, the presence of more than one chronic disease (OR 4.0, 95%CI: 1.3–12.7; OR 3.4, 95% CI: 1.2–10.1), high levels of pre migration stressors (OR 3.6, 95% CI: 1.1–11.9; OR 3.3, 95% CI: 1.0–10.4) or post migration stressors (OR 17.3, 95% CI: 4.9–60.8; OR 3.9, 95% CI: 1.2–12.3) were independent predictors of self reported PTSD or depression/anxiety symptoms respectively, however, residence status was no longer significantly associated with PTSD or depression/anxiety. Residence status may act as a marker for other explanatory variables; our results show it has a strong relationship with post migration stressors (χ2 = 19.74, df = 1, P < 0.001).
In terms of health care utilisation, asylum seekers use GP services more often than refugees, while no significant difference was found between these groups for use of dentists, medication, hospitalisation or mental health services.
Asylum seekers have a higher level of self reported PTSD and depression/anxiety symptoms compared to refugees. However, residence status appears to act as a marker for post migration stressors. Compared to refugees, asylum seekers utilise GP services more often, but not mental health services.
PMCID: PMC2711949  PMID: 19566954

Results 1-5 (5)