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author:("Tu, mianzhu")
1.  A Consideration of Genetic Mechanisms Behind the Development of Hypertension in Blacks 
Current hypertension reports  2013;15(2):108-113.
Hypertension is a more serious disease in blacks. The determinants of the blood pressure (BP) may be uniquely different from those in whites. The characteristic low-renin, salt-sensitive hypertension of blacks is consistent with the kidney reabsorbing additional sodium (Na), which leads to an expanded plasma volume that drives the BP. Mechanisms considered are genetically based. These include: (1) the intra-renal renin-angiotensin system (RAS), one based on molecular variations in angiotensinogen; (2) the Na, K, 2Cl cotransporter (NKCC2) and its regulators in the thick ascending limb, which are associated with a variety of phenotypes consistent with a more active cotransporter in blacks; and (3) the genes for MYH9 and APOL 1, which have been associated with kidney disease in blacks. To achieve a state of hypertension, an increase in Na uptake in proximal nephron regions may require a distal nephron that does not fully adjust due to less than adequate suppression of aldosterone production.
PMCID: PMC3594543  PMID: 23397215
Race; Hypertension; Extracellular fluid volume; Angiotensinogen; Renin; Angiotensin II; Aldosterone; Proximal tubule; Thick ascending limb; Calcium-sensing receptor; NKCC2; MYH9; APOL 1; Epithelial sodium channel; Sodium; Potassium; Calcium
2.  High Frequency of Human Papillomavirus Detection in the Vagina Before First Vaginal Intercourse Among Females Enrolled in a Longitudinal Cohort Study 
The Journal of Infectious Diseases  2012;207(6):1012-1015.
Background. Genital human papillomavirus (HPV) infection is believed to be primarily sexually transmitted. Few studies have documented the detection of HPV in the vagina before first vaginal intercourse.
Methods. We used a longitudinally followed cohort of adolescent females without prior vaginal intercourse to examine the frequency of detection of vaginal HPV and the association between first reported HPV detection and noncoital sexual behaviors.
Results. HPV was detected in 45.5% of subjects (10 of 22) before first vaginal sex. Seven of these 10 subjects reported noncoital behaviors that, in part, might have explained genital transmission.
Conclusions. HPV can be detected in the vagina before first sexual intercourse, highlighting the need for early vaccination.
PMCID: PMC3571440  PMID: 23242538
human papillomavirus; sexual behaviors; adolescents
3.  Somatic Symptoms in Cancer Patients Trajectory Over 12 Months and Impact on Functional Status and Disability 
Cross-sectional studies have established the prevalence and functional impairment of somatic symptoms in cancer patients. The purpose of this study was to determine the trajectory and adverse consequences of such symptoms over time.
Secondary analysis of longitudinal data from 405 cancer patients enrolled in a telecare management trial for pain and/or depression. Somatic symptom burden was measured with a 22-item scale at baseline, 1, 3, 6, and 12 months. Outcomes included the SF-12 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores, the Sheehan Disability Scale (SDS) score and self-reported total disability days (TDD). Mixed methods repeated measures (MMRM) analyses were conducted to determine whether antecedent change in somatic symptom burden predicted functional status and disability.
Symptoms were highly prevalent at baseline, with 15 of the 22 symptoms endorsed by more than half of the patients. A rather constant cross-sectional prevalence over 12 months at the group level belied a quite different trajectory at the patient level where the median persistence, resolution and incidence rates for 14 of the most common symptoms were 39%, 37%, and 24%, respectively. A clinically significant (i.e., 5 points) reduction in somatic symptom burden predicted improvement in PCS, MCS, and SDI (all P < .001), as well as a lower likelihood of ≥ 14 disability days in the past 4 weeks (odds ratio, 0.84; 95% CI, 0.74 to 0.95).
Somatic symptoms remain burdensome in cancer patients over 12 months and symptom improvement predicts significantly better functional status and less disability.
PMCID: PMC3543758  PMID: 22941116
cancer; somatic symptoms; prognosis; disability; quality of life; functional status; symptom burden
4.  Anxiety but not Social Stressors Predict 12-Month Depression and Pain Severity 
The Clinical journal of pain  2013;29(2):95-101.
To determine whether baseline anxiety and social stressors as well their early change (first 3 months) predict 12 month depression and pain severity.
We analyzed data from the Stepped Care for Affective Disorders and Musculoskeletal Pain study, a randomized clinical trial of a combined medication-behavioral intervention for primary care patients with chronic musculoskeletal pain and depression. Using multivariable linear regression modeling, we examined the independent association of baseline anxiety and social stressors with depression and pain severity at 12 months. Additionally, we modeled whether changes in anxiety and social stressors predicted 12 month depression and pain severity.
Overall, the sample (N = 250) was 52.8% women with a mean age of 55.5 years, and a racial distribution of 60.4% White, 36.4% Black, and 3.2% other. Depression and pain were moderately severe at baseline (mean SCL-20 depression = 1.9 and BPI pain severity = 6.15) and similar across intervention and usual care arms. Baseline anxiety symptoms predicted both depression (t score = 2.13, p = 0.034) and pain severity (t score = 2.75, p = 0.007) at 12 months. Also, early change in anxiety predicted 12-month depression (t score = −2.47, p = .014), but not pain. Neither baseline nor early change in social stressors predicted depression or pain severity.
Anxiety, but not social stressors predict 12 month depression and pain severity. The presence of comorbid anxiety should be considered in the assessment and treatment of patients with musculoskeletal pain and depression, particularly as a factor that may adversely affect treatment response.
PMCID: PMC3529840  PMID: 23183264
Depression; pain; anxiety; stress; primary care
5.  Longitudinal Comparison of Three Depression Measures in Adult Cancer Patients 
Although a number of depression measures have been used with cancer patients, longitudinal comparisons of several measures in the same patient population have been infrequently reported.
To compare the Hopkins Symptom Checklist-20 (HSCL-20), SF-36 Mental Health Inventory (MHI-5), and Patient Health Questionnaire-9 (PHQ-9) in adults with cancer.
Of 309 cancer patients enrolled in a telecare management trial for depression, 247 completed the three depression measures at both baseline and at three months, as well as a retrospective assessment of global rating of change in depression at three months. Internal consistency and construct validity of each measure was evaluated. Responsiveness was compared by calculating standardized response means (SRM) and receiver operating characteristic area under the curve (AUC), using global rating of change as the external comparator measure. Differences between intervention and control groups in depression change scores were compared by calculating standardized effect sizes (SES).
Internal reliability coefficients for the three measures were ≥ 0.77 at baseline and ≥ 0.84 at three months. Construct validity was supported with strong correlations of the depression measures among themselves, moderately strong correlations with other measures of mental health, and moderate correlations with vitality and disability. In terms of responsiveness, SRMs for all measures significantly differentiated between three groups (improved, unchanged, worse) as classified by patient-reported global rating of change in depression at three months. The three measures were able to detect a modest treatment effect in the intervention group compared with the control group (SES ranging from 0.21 to 0.43) in the full sample, whereas detecting a greater treatment effect in depressed participants with comorbid pain (SES ranging from 0.30 to 0.58). Finally, the three measures performed similarly in detecting patients with improvement.
The HSCL-20, MHI-5, and PHQ-9 were established as reliable, valid, and responsive depression measures in adults with cancer. Given current recommendations for measurement-based care, our study shows that clinicians treating depressed cancer patients have several measures from which to choose.
PMCID: PMC3538946  PMID: 22921152
Cancer; depression; assessment; psychometrics; HSCL-20; MHI-5; PHQ-9; responsiveness
6.  Cost Analysis of the Geriatric Resources for Assessment and Care of Elders Care Management Intervention 
To provide, from the healthcare delivery system perspective, a cost analysis of the Geriatric Resources for Assessment and Care of Elders (GRACE) intervention, which is effective in improving quality of care and outcomes.
Randomized controlled trial with physicians as the unit of randomization.
Community-based primary care health centers.
Nine hundred fifty-one low-income seniors aged 65 and older; 474 participated in the intervention and 477 in usual care.
Home-based care management for 2 years by a nurse practitioner and social worker who collaborated with the primary care physician and a geriatrics interdisciplinary team and were guided by 12 care protocols for common geriatric conditions.
Chronic and preventive care costs, acute care costs, and total costs in the full sample (n =951) and predefined high-risk (n =226) and low-risk (n =725) groups.
Mean 2-year total costs for intervention patients were not significantly different from those for usual care patients in the full sample ($14,348 vs $11,834; P =.20) and high-risk group ($17,713 vs $18,776; P =.38). In the high-risk group, increases in chronic and preventive care costs were offset by reductions in acute care costs, and the intervention was cost saving during the postintervention, or third, year ($5,088 vs $6,575; P < .001). Mean 2-year total costs were higher in the low-risk group ($13,307 vs $9,654; P =.01).
In patients at high risk of hospitalization, the GRACE intervention is cost neutral from the healthcare delivery system perspective. A cost-effectiveness analysis is needed to guide decisions about implementation in low-risk patients.
PMCID: PMC3874584  PMID: 19691149
cost analysis; primary care; geriatric assessment; care management; interdisciplinary team
7.  Hospice Use Among Nursing Home Patients 
Journal of the American Medical Directors Association  2012;14(4):10.1016/j.jamda.2012.10.006.
Among hospice patients who lived in nursing homes, we sought to: (1) report trends in hospice use over time, (2) describe factors associated with very long hospice stays (>6 months), and (3) describe hospice utilization patterns.
Design, setting, and participants
We conducted a retrospective study from an urban, Midwest cohort of hospice patients, aged ≥65 years, who lived in nursing homes between 1999 and 2008.
Demographic data, clinical characteristics, and health care utilization were collected from Medicare claims, Medicaid claims, and Minimum Data Set assessments. Patients with overlapping nursing home and hospice stays were identified. χ2 and t tests were used to compare patients with less than or longer than a 6-month hospice stay. Logistic regression was used to model the likelihood of being on hospice longer than 6 months.
A total of 1452 patients received hospice services while living in nursing homes. The proportion of patients with noncancer primary hospice diagnoses increased over time; the mean length of hospice stay (114 days) remained high throughout the 10-year period. More than 90% of all patients had 3 or more comorbid diagnoses. Nearly 20% of patients had hospice stays longer than 6 months. The hospice patients with stays longer than 6 months were observed to have a smaller percentage of cancer (25% vs 30%) as a primary hospice diagnosis. The two groups did not differ by mean cognitive status scores, number of comorbidities, or activities of daily living impairments. The greater than 6 months group was much more likely to disenroll before death: 33.9% compared with 13.8% (P < .0001). A variety of patterns of utilization of hospice across settings were observed; 21 % of patients spent some of their hospice stay in the community.
Any policy proposals that impact the hospice benefit in nursing homes should take into account the difficulty in predicting the clinical course of these patients, varying utilization patterns and transitions across settings, and the importance of supporting multiple approaches for delivery of palliative care in this setting.
PMCID: PMC3820369  PMID: 23181979
Hospice; nursing home; utilization; policy
Vaccine  2012;30(37):5496-5499.
Human papillomavirus (HPV) vaccine trials have demonstrated high efficacy in preventing HPV infections and HPV related disease in females ages 16–26. However, there is no source data to demonstrate the impact of the vaccine in other populations who may be at higher risk for HPV related disease. This study examines the impact of HPV vaccination on subsequent HPV detection and sexual behaviors among urban adolescents in a clinical setting.
A cohort of adolescent women, ages 14 to 17, were recruited prospectively and matched to historical controls to assess the impact of HPV vaccination. All women completed the same questionnaire and face-to-face interview that assessed sexual behaviors; all provided a clinician or self-collected vaginal swab that was used to test for sexually transmitted infections, including HPV. Logistic regression models, incorporating random pair effects, were used to assess the impact of the HPV vaccine on HPV detection and sexual behaviors between the two groups.
Each woman recruited (N=75) was matched to 2 historical controls (HC); most of the recruited women (89.3%) had received one or more doses of the HPV vaccine. At enrollment, detection of quadrivalent vaccine types (HPV 6, 11, 16 and 18) was significantly less in the recruited group (5.3%) as compared to the HC (24%): OR=5.6 (CI=1.9, 16.5), p=.002. Adolescent women in the HC had a 9.5 times greater odds of HPV infection when the analysis was adjusted to compare those who had 2 or more vaccine doses to their matched controls. The only behavioral difference found was that the recruited women used condoms more frequently.
This study demonstrates that HPV vaccination was associated with fewer vaccine-type HPV infections despite incomplete vaccination and high risk sexual behaviors. These data also suggest that sexual behaviors were not altered because of the vaccine.
PMCID: PMC3423324  PMID: 22750043
Human papillomavirus vaccination; human papillomavirus infection; adolescent
9.  Predictors of Cancer-related Pain Improvement Over Time 
Psychosomatic Medicine  2012;74(6):642-647.
To determine the predictors of pain improvement among patients being treated for cancer-related pain over 12 months.
A secondary analysis of the Indiana Cancer Pain and Depression (INCPAD) trial was performed. Patients participating in this telephone care management pain and depression intervention trial (N=274, mean age=58.1±10.5 years, 66.1% women) were interviewed at baseline, and 1, 3, 6, and 12 months. Pain improvement outcomes included both a continuous measure (Brief Pain Inventory score) and a categorical measure (pain improved vs. pain not improved). Predictor variables included change in depression, age, gender, race, marital status, socioeconomic disadvantage, medical comorbidity, type of cancer, and phase of cancer. Multivariable repeated measures were conducted adjusting for intervention group assignment, baseline pain severity, and time in months since baseline assessment.
Factors predicting both continuous and categorical pain improvement included participating in the intervention group (beta=−.92, p<.001; OR=2.53, CI=1.65–3.89), greater improvement in depression (beta=−.31, p=.003; OR=1.84, CI=1.35–2.51), higher socioeconomic status (Socioeconomic Disadvantage Index; beta=.25, p=.034; OR=.73, CI=.56–.94), and fewer comorbid conditions (beta=.20, p=.002; OR=.84, CI=.73–.96). Conversely, patients with more severe pain at baseline or with recurrent or progressive cancer were less likely to experience continuous or categorical pain improvement, respectively.
Effective management of depression and comorbid conditions along with improvement of social services could be critical components of a comprehensive pain management plan. Also, patients with more severe pain or with recurrent or progressive cancers may require closer monitoring and adequate treatment of pain.
Clinical Trial Registration Number
PMCID: PMC3392436  PMID: 22753637
Cancer-related pain; pain improvement; predictors; longitudinal study
10.  Adolescent Romantic Couples Influence on Substance Use in Young Adulthood 
Journal of Adolescence  2011;35(3):638-647.
Research has demonstrated that adolescent peer group affiliations are consistent predictors ofsubstance use initiation and maintenance; it is less clear how adolescent romantic relationships influence substance use behavior. Data were drawn from the National Longitudinal Study of Adolescent Health. Participants in the final dataset for the current study includedadolescents (321 males and 321 females) who were identified in reciprocated romantic relationships at Wave 1 (1994-1995; mean age 16.7 years) that were followed into young adulthood and reassessed at two different time points (Wave 2 in 1996, mean age 17.7, and Wave 3 in 2001-2002, mean age 23.1). Data were gathered from both partners, and included demographic variables, longitudinal measures of substance use (alcohol, tobacco, and marijuana), and relationship seriousness. Hierarchical linear modeling using SAS PROC MIXED were utilized to test for individual versus partner influences. Results revealed individual and partner effects for the prediction of alcohol and tobacco, although individual effects were generally greater than partner influences. For marijuana use, as self-reported relationship seriousness increased, future marijuana use decreased. These findings suggest the developmental significance of adolescent romantic relationships on the prediction of future substance use behavior during young adulthood.
PMCID: PMC3250563  PMID: 21907401
Adolescence; romantic relationships; development; longitudinal; substance use
11.  A Comparison and Cross-Validation of Models to Predict Basic Activity of Daily Living Dependency in Older Adults 
Medical Care  2012;50(6):534-539.
A simple method of identifying elders at high risk for Activity of Daily Living dependence (ADL) could facilitate essential research and implementation of cost-effective clinical care programs.
We used a nationally representative sample of 9,446 older adults free from ADL dependence in 2006 to develop simple models for predicting ADL dependence at 2008 follow-up and to compare the models to the most predictive published model. Candidate predictor variables were those of published models that could be obtained from interview or medical records data.
Variable selection was performed using logistic regression with backwards elimination in a two-thirds random sample (n=6,233) and validated in a one-third random sample (n=3,213). Model fit was determined using the c-statistic and evaluated vis-à-vis our replication of a published model.
At 2-year follow-up, 8.0% and 7.3% of initially independent persons were ADL dependent in the development and validation samples, respectively. The best fitting, simple model consisted of age and number of hospitalizations in past 2 years, plus diagnoses of diabetes, chronic lung disease, congestive heart failure, stroke, and arthritis. This model had a c-statistic of 0.74 in the validation sample. A model of just age and number of hospitalizations achieved a c-statistic of 0.71. These compared to a c-statistic of 0.79 for the published model. Sensitivity analyses demonstrated model robustness.
Models based on widely available data achieve very good validity for predicting ADL dependence. Future work will assess the validity of these models using medical records data.
PMCID: PMC3351695  PMID: 22581013
Older Adults; Activities of Daily Living; Models of Care
12.  Semiparametric Frailty Models for Clustered Failure Time Data 
Biometrics  2011;68(2):429-436.
We consider frailty models with additive semiparametric covariate effects for clustered failure time data. We propose a doubly penalized partial likelihood (DPPL) procedure to estimate the nonparametric functions using smoothing splines. We show that the DPPL estimators could be obtained from fitting an augmented working frailty model with parametric covariate effects, whereas the nonparametric functions being estimated as linear combinations of fixed and random effects, and the smoothing parameters being estimated as extra variance components. This approach allows us to conveniently estimate all model components within a unified frailty model framework. We evaluate the finite sample performance of the proposed method via a simulation study, and apply the method to analyze data from a study of sexually transmitted infections (STI).
PMCID: PMC3600835  PMID: 22070739
Doubly penalized partial likelihood; smoothing spline; Gaussian frailty; sexually transmitted disease; Smoothing parameter; Variance components
13.  Transitions in Care among Older Adults with and without Dementia 
Transition to nursing facilities is often viewed as the final stage of care for persons with dementia in a progression toward dependency
Describe transitions in care among persons with dementia with attention to nursing facility transitions
prospective cohort
public health system
4,197 community-dwelling older adults
Subjects’ electronic medical records were merged with Medicare claims, Medicaid claims, the Minimum Dataset (MDS), and the Outcome and Assessment Information Set (OASIS) from 2001–2008 with a mean follow-up of 5.2 years
Compared to subjects never diagnosed (n=2,674), older adults with prevalent (n=524) or incident dementia (n=999) had greater Medicare (11.4% v. 44.7% v. 44.8%, p=<.0001) and Medicaid (1.4% v. 21.0% v. 16.8%, p<.0001) nursing facility use, greater hospital (51.2% v. 76.2% v. 86.0%, p< .0001) and home health use (27.3% v. 55.7%, 65.2%, p< .0001), more transitions in care per person year of follow-up (1.4 v. 2.6 v. 2.7, p<.0001), and more mean total transitions (3.8 v. 11.2 v. 9.2, p<.0001). Among the 1,523 subjects with dementia, 74.5% of transitions to nursing facilities were transfers from hospitals. Among transitions from nursing facilities, the conditional probability was 41.0% for a return home without home health care, 10.7% for home health care, and 39.8% for a hospital transfer. Among subjects with dementia with a ≤30-day rehospitalization, 45% had been discharged to nursing facilities from the index hospitalization. At time of death, 46% of subjects with dementia were at home, 35% in the hospital, and 19% in a nursing facility.
Patients with dementia live and frequently die in community settings. Nursing facilities are part of a dynamic network of care characterized by frequent transitions.
PMCID: PMC3354737  PMID: 22587849
14.  Cancer-Related Pain and Disability: A Longitudinal Study 
Although the cross-sectional association between cancer-related pain and disability is well-established, their longitudinal relationship has been less studied.
Data from the Indiana Cancer Pain and Depression (INCPAD) trial was analyzed to determine whether baseline cancer-related pain and changes in pain over time predict disability over 12 months.
A total of 274 cancer survivors with cancer-related pain were accrued in the INCPAD trial. Data were collected at baseline, 1, 3, 6, and 12 months by interviewers blinded to treatment arm. Disability outcomes included a continuous measure (Sheehan Disability Scale score) and a categorical measure (≥ 14 days in the past four weeks with a ≥ 50% reduction in usual activities). Predictor variables, operationalized by the Brief Pain Inventory, included baseline pain severity and changes in pain severity scores between each time point. Multivariable analyses were conducted adjusting for treatment group, baseline disability, and selected covariates including depression.
Baseline pain severity did not predict disability outcomes at 12 months. However, improvement in pain severity predicted less disability over 12 months both in terms of Sheehan Disability Scale scores (b = −0.17, t = −5.33, P< 0.001) and ≥ 14 disability days in the past month (odds ratio = 0.85; 95% confidence interval, 0.79–0.93; P< 0.001).
Disability over 12 months in patients with cancer-related pain is predicted by changes in pain severity over time. Results suggest that effective pain management may reduce subsequent disability among cancer survivors.
PMCID: PMC3158243  PMID: 21570808
Cancer-related pain; disability; longitudinal study
15.  Intensified Effect of Adiposity on Blood Pressure in Overweight and Obese Children 
Hypertension  2011;58(5):818-824.
In children, blood pressure (BP) and risk for hypertension are proportional to degree of adiposity. Whether the relationship to BP is similar over the full range of adiposity is less clear. Subjects from a cohort study (n=1,111; 50% male and 42% black) contributed 9,102 semiannual BP and height/weight assessments. The mean enrollment age was 10.2 years and mean follow-up was 4.5 years. Adiposity was expressed as body mass index (BMI) percentile, which accounted for effects of age and sex. The following observations were made. The effect of relative adiposity on BP was minimal until the BMI percentile reached 85, beginning of the overweight category, at which point the effect of adiposity on BP increased by four-fold. Similarly intensified adiposity effects on BP were observed in children aged 10 or younger, 11 to 14 years, and 15 years or older. Serum levels of the adipose tissue-derived hormone, leptin, together with heart rate showed an almost identically patterned relation to BP to that of BMI percentile and BP thus implicating a possible mediating role for leptin. In conclusion, there is a marked intensification of the influence of adiposity on BP when children reach the categories of overweight and obese. Among the possible pathways, leptin may be a potentially important mediator acting through the sympathetic nervous system (reflected in heart rate). The findings have relevance to interventions designed to prevent or treat adiposity-related increases in BP and to the analytical approaches used in epidemiologic studies.
PMCID: PMC3433397  PMID: 21968752
Hypertension; obesity; leptin; heart rate; sympathetic nervous system
16.  Comparative effects of non-steroidal anti-inflammatory drugs (NSAIDs) on blood pressure in patients with hypertension 
Nonsteroidal anti-inflammatory drugs (NSAIDs) may disrupt control of blood pressure in hypertensive patients and increase their risk of morbidity, mortality, and the costs of care. The objective of this study was to examine the association between incident use of NSAIDs and blood pressure in patients with hypertension.
We conducted a retrospective cohort study of adult hypertensive patients to determine the effects of their first prescription for NSAID on systolic blood pressure and antihypertensive drug intensification. Data were collected from an electronic medical record serving an academic general medicine practice in Indianapolis, Indiana, USA. Using propensity scores to minimize bias, we matched a cohort of 1,340 users of NSAIDs with 1,340 users of acetaminophen. Propensity score models included covariates likely to affect blood pressure or the use of NSAIDs. The study outcomes were the mean systolic blood pressure measurement after starting NSAIDs and changes in antihypertensive therapy.
Compared to patients using acetaminophen, NSAID users had a 2 mmHg increase in systolic blood pressure (95% CI, 0.7 to 3.3). Ibuprofen was associated with a 3 mmHg increase in systolic blood pressure compared to naproxen (95% CI, 0.5 to 4.6), and a 5 mmHg increase compared to celecoxib (95% CI, 0.4 to 10). The systolic blood pressure increase was 3 mmHg in a subgroup of patients concomitantly prescribed angiotensin converting enzyme inhibitors or calcium channel blockers and 6 mmHg among those prescribed a beta-adrenergic blocker. Blood pressure changes in patients prescribed diuretics or multiple antihypertensives were not statistically significant.
Compared to acetaminophen, incident use of NSAIDs, particularly ibuprofen, is associated with a small increase in systolic blood pressure in hypertensive patients. Effects in patients prescribed diuretics or multiple antihypertensives are negligible.
PMCID: PMC3502533  PMID: 23092442
NSAIDs; Hypertension; Blood pressure; Propensity score
17.  A Stochastic Model for Assessing Chlamydia trachomatis Transmission Risk Using Longitudinal Observational Data 
Bacterium Chlamydia trachomatis causes genital chlamydia infection. Yet little is known about the transmission efficiency of this organism. Ethical constraint against exposing healthy subjects to infected partners precludes the possibility of quantifying transmission risk through controlled experiments. This research proposes an alternative strategy that relies on observational data. Specifically, we present a stochastic model that treats longitudinally observed infection states in a group of young women as a Markov process. The proposed model explicitly accommodates the parameters of C. trachomatis transmission, including per-encounter sexually transmitted infection (STI) acquisition risks, with and without condom protection, and the probability of antibiotic treatment failure. The male-to-female transmission probability of C. trachomatis is then estimated by combining the per-encounter disease acquisition risk and the organism’s prevalence in the male partner population. The proposed model is fitted in a Bayesian computational framework.
PMCID: PMC3197250  PMID: 22022023
Binary outcome; Bacterial infection; Transmission probability; Longitudinal study; Markov model; MCMC; Observational data
18.  Reciprocal Relationship between Pain and Depression: A 12-Month Longitudinal Analysis in Primary Care 
Pain and depression are the most prevalent physical and psychological symptom-based disorders, respectively, and co-occur 30–50% of the time. However, their reciprocal relationship and potentially causative effects on one another have been inadequately studied. Longitudinal data analysis involving 500 primary care patients with persistent back, hip or knee pain were enrolled in the Stepped Care for Affective Disorders and Musculoskeletal Pain (SCAMP) study. Half of the participants had comorbid depression and were randomized to a stepped care intervention (n = 123) or treatment as usual (n = 127). Another 250 nondepressed patients with similar pain were followed in a parallel cohort. Outcomes were assessed at baseline, 3, 6, and 12 months. Mixed effects model repeated measures (MMRM) multivariable analyses were conducted to determine if change in pain severity predicted subsequent depression severity, and vice-versa. Change in pain was a strong predictor of subsequent depression severity (t-value = 6.63, p < .0001). Likewise, change in depression severity was an equally strong predictor of subsequent pain severity (t-value = 7.28, p < .0001). Results from the full cohort were similar in the clinical trial subgroup. In summary, pain and depression have strong and similar effects on one another when assessed longitudinally over 12 months.
PMCID: PMC3222454  PMID: 21680251
pain; depression; causation; prognosis; primary care; longitudinal
19.  Data for drugs available through low-cost prescription drug programs are available through pharmacy benefit manager and claims data 
Observational data are increasingly being used for pharmacoepidemiological, health services and clinical effectiveness research. Since pharmacies first introduced low-cost prescription programs (LCPP), researchers have worried that data about the medications provided through these programs might not be available in observational data derived from administrative sources, such as payer claims or pharmacy benefit management (PBM) company transactions.
We used data from the Indiana Network for Patient Care to estimate the proportion of patients with type 2 diabetes to whom an oral hypoglycemic agent was dispensed. Based on these estimates, we compared the proportions of patients who received medications from chains that do and do not offer an LCPP, the proportion trend over time based on claims data from a single payer, and to proportions estimated from the Medical Expenditure Panel Survey (MEPS).
We found that the proportion of patients with type 2 diabetes who received oral hypoglycemic medications did not vary based on whether the chain that dispensed the drug offered an LCPP or over time. Additionally, the rates were comparable to those estimated from MEPS.
Researchers can be reassured that data for medications available through LCPPs continue to be available through administrative data sources.
PMCID: PMC3416643  PMID: 22726249
Low-cost prescription program; Oral antihyperglycemic agents; Pharmacy benefit manager; Claims data
20.  Risk of hyperkalemia associated with selective COX-2 inhibitors† 
Pharmacoepidemiology and drug safety  2010;19(11):1194-1198.
Selective cyclooxygenase-2 (COX-2) inhibitors have been linked to cardiac death. The mechanism for this adverse effect appears to be by ischemic insult; however another mechanism could involve hyperkalemia. The objective of this study was to determine the effects of selective COX-2 inhibitors and non-selective nonsteroidal anti-inflammatory drugs (NSAIDs) on serum potassium concentration and the electrocardiogram.
A retrospective cohort study was conducted using propensity score matching of patients from an inner-city academic medical center at Indianapolis, Indiana. Two hundred and two patients prescribed selective COX-2 inhibitors were matched to 202 patients prescribed non-selective NSAIDs using propensity scores methods. Outcomes included change in serum potassium concentration from baseline and the risk of an abnormal electrocardiogram.
Compared to patients prescribed non-selective NSAIDs, those prescribed a selective COX-2 inhibitor had a higher risk of serum potassium increase greater than 5 mEq/L (OR, 2.56; 95%CI, 1.03–6.36). However, patients prescribed selective COX-2 inhibitors had no greater risk of electrocardiogram abnormality (OR, 1.16; 95%CI, 0.74–1.82).
Selective COX-2 inhibitors may have a greater risk of hyperkalemia than non-selective NSAIDs. This study was exploratory with small numbers of patients. Further studies are needed to confirm these results and any association with cardiovascular events.
PMCID: PMC3018679  PMID: 20842761
hyperkalemia; NSAIDs; selective COX-2 inhibitors; retrospective cohort study; propensity score
21.  Somatic Symptoms in Cancer Patients with Pain and/or Depression Prevalence, Disability, and Health Care Use 
Archives of internal medicine  2010;170(18):1686-1694.
The adverse impact of high somatic symptom burden is well established for primary care and other noncancer populations with chronic medical disorders. This study examines the impact of somatic symptom burden on disability and health care use in cancer patients suffering from pain and/or depression.
Secondary analysis of baseline data from 405 cancer patients enrolled in a telecare management trial for pain and/or depression. Somatic symptom burden was measured with a 22-item scale. Multivariable models were conducted to determine the association of somatic symptom burden with the Sheehan Disability Scale (SDS) score, the number of self-reported disability days in the past 3 months, and health care use. Models were adjusted for sociodemographic characteristics, medical comorbidity, and depression and pain severity.
Somatic symptoms were highly prevalent, with 15 of the 22 symptoms reported by more than 50% of patients. Somatic symptom burden was similar across different types and phases of cancer. The mean SDS (scored 0 to 10) was 5.4 and the mean number of self-reported disability days in the past 4 weeks was 16.9 days. In multivariable models, somatic symptom burden was associated with both SDS (P < .001) and the likelihood of ≥ 14 disability days in the past 4 weeks (OR=1.51; 95% CI, 1.19–1.92) but was not with increased health care use.
Somatic symptom burden is high in cancer patients with pain and/or depression. Given the strong association with disability and the high prevalence of many types of symptoms, recognizing and managing somatic symptoms may be important in improving quality of life and functional status regardless of type or phase of cancer.
PMCID: PMC3174492  PMID: 20937930
cancer; somatic symptoms; somatization; pain; depression; disability; quality of life; health care use
22.  The Association of Depression and Pain with Health-Related Quality of Life, Disability, and Health Care Use in Cancer Patients 
Pain and depression are two of the most prevalent and treatable cancer-related symptoms, each present in at least 20-30% of oncology patients.
To determine the associations of pain and depression with health-related quality of life (HRQL), disability, and health care use in cancer patients.
The Indiana Cancer Pain and Depression (INCPAD) study is a randomized clinical trial comparing telecare management vs. usual care for patients with cancer-related pain and/or clinically significant depression. In this paper, baseline data on patients enrolled from 16 urban or rural community-based oncology practices are analyzed to test the associations of pain and depression with HRQL, disability, and health care use.
Of the 405 participants, 32% had depression only, 24% pain only, and 44% both depression and pain. The average Hopkins Symptom Checklist 20-item (HSCL-20) depression score in the 309 depressed participants was 1.64 (on 0-4 scale), and the average Brief Pain Inventory (BPI) severity score in the 274 participants with pain was 5.2 (on 0-10 scale), representing at least moderate levels of symptom severity. Symptom-specific disability was high, with participants reporting an average of 16.8 days out of the past 28 (i.e., 60% of their days in the past four weeks) in which they were either confined to bed (5.6 days) or had to reduce their usual activities by 50% (11.2 days) due to pain or depression. Moreover, 176 (43%) reported being unable to work due to health-related reasons. Depression and pain had both individual and additive adverse associations with quality of life. Most patients were currently not receiving care from a mental health or pain specialist.
Depression and pain are prevalent and disabling across a wide range of types and phases of cancer, commonly co-occur, and have additive adverse effects. Enhanced detection and management of this disabling symptom dyad is warranted.
PMCID: PMC2934745  PMID: 20580201
Cancer; pain; depression; disability; quality of life; health care use
23.  Effect of Telecare Management on Pain and Depression in Patients with Cancer: A Randomized Trial 
Pain and depression are two of the most prevalent and treatable cancer-related symptoms, yet frequently go unrecognized and/or undertreated.
To determine whether centralized telephone-based care management coupled with automated symptom monitoring can improve depression and pain in cancer patients.
Design, Setting, and Patients
Randomized controlled trial conducted in 16 community-based urban and rural oncology practices across the state of Indiana. Recruitment occurred from March 2006 through August 2008 and follow-up concluded in August 2009. The 405 patients had depression (Patient Health Questionnaire-9 score ≥ 10), cancer-related pain (Brief Pain Inventory worst pain score ≥ 6), or both.
Patients were randomly assigned to the intervention (n=202) or to usual care (n=203), stratified by symptom type. Intervention patients received centralized telecare management by a nurse-physician specialist team coupled with automated home-based symptom monitoring by interactive voice recording or internet.
Main Outcome Measures
Blinded assessment at baseline, 1, 3, 6, and 12 months for depression (20-item Hopkins Symptom Checklist [HSCL-20]) and pain (Brief Pain Inventory [BPI]) severity.
There were 131 patients enrolled with depression only, 96 with pain only, and 178 with both depression and pain. Of the 274 patients enrolled for pain, the 137 intervention patients had greater improvements than the 137 usual care patients in BPI pain severity over the 12 months of the trial whether measured as a continuous severity score or as a categorical pain responder (P < .0001 for both). Similarly, of the 309 patients enrolled for depression, the 154 intervention patients had greater improvements than the 155 usual care patients in HSCL-20 depression severity over the 12 months of the trial whether measured as a continuous severity score (P < .0001) or as a categorical depression responder (P < .001). The standardized effect size for between-group differences at 3 and 12 months was .67 and .39 for pain, and .42 and .44 for depression.
Centralized telecare management coupled with automated symptom monitoring resulted in improved pain and depression outcomes in cancer patients receiving care in geographically-dispersed urban and rural oncology practices.
PMCID: PMC3010214  PMID: 20628129
cancer; pain; depression; antidepressants; analgesics; telemedicine; care management
24.  The Association of Depression and Anxiety with Health-Related Quality of Life in Cancer Patients with Depression and/or Pain 
Psycho-oncology  2010;19(7):734-741.
Depression is known to be a major problem in cancer patients, and evidence is emerging about the importance of anxiety. Because the disorders are highly comorbid, we examined the relationship of anxiety and depression with health-related quality of life (HRQL) in cancer patients.
Sample included 405 adult oncology patients participating in a randomized controlled trial of telecare management for pain and depression. This secondary cross-sectional analysis of baseline data examined independent and additive effects of anxiety and depression on HRQL, disability, and somatic symptom severity.
In 397 patients who screened positive for either pain or depression or both, 135 had comorbid anxiety and depression, 174 had depression but not anxiety, and 88 had neither. Differences existed across all non-physical HRQL domains and were more pronounced incrementally across the 3 groups in the expected direction. In GLM modeling, anxiety and depression were each associated with all domains when modeled separately (p < 0.0001). When modeled together, anxiety and depression had independent and additive effects on the mental health domains of HRQL and on somatic symptom burden. In other domains (vitality, perceived disability, overall quality of life, and general health perceptions), only depression had an effect.
Anxiety and depression have strong and independent associations with mental health domains and somatic symptom burden in cancer patients. However, depression has a more pervasive association with multiple other domains of HRQL. Paying attention to both anxiety and depression may be particularly important when addressing mental health needs and somatic symptom distress.
PMCID: PMC2888919  PMID: 19777535
Cancer; oncology; anxiety; depression; symptoms; health-related quality of life
25.  Characteristics Associated with Sex After Periods of Abstinence Among Sexually Experienced Young Women 
Adolescent pregnancy prevention is difficult because sex itself is intermittent, occurring after days, weeks or months of abstinence. An understanding of why sexually experienced adolescents decide to have sex after a period of abstinence will allow clinicians to better tailor counseling.
For up to 4.5 years, 354 adolescent women were interviewed and STI tested every three months, and asked to complete 3 months of daily diaries twice a year. We examined periods of abstinence in the daily diaries, using survival analysis to estimate the effect of intrapersonal, relationship, and STI-related factors on the risk of ending an abstinence period with sex.
Participants reported 9236 abstinence periods, mean 30.9 days. Shorter, intermediate and longer abstinence periods were identified from the cumulative hazard plot. The risk of ending a shorter abstinence period increased with age (Hazard Ratio = 1.07), sexual interest (HR = 1.14), positive mood (HR = 1.03), daily partner support (HR=1.14), quarterly relationship quality (HR=1.02) and distant STI (HR=1.16); the risk decreased with negative mood (HR=0.98) and recent STI (HR=0.91). During intermediate periods the association with recent STI switched directions (HR=1.40). Longer periods showed associations only with age (HR=1.24), sexual interest (HR=1.33), and relationship quality (HR=1.10).
Intrapersonal, relationship, and STI related factors influence the decision to have sex after a period of abstinence. The direction and strength of these associations varied with the length of abstinence, highlighting the importance of a young woman's recent patterns of sexual activity.
PMCID: PMC3034242  PMID: 20415884
Sexual Abstinence; Adolescent; Sexually Transmitted Disease; Sexual Behavior; Affect; Survival Analysis; Sexual Desire; Sexual Partner

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