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author:("Tu, mianzhu")
1.  Comparative Responsiveness of Pain Measures in Cancer Patients 
Brief measures to assess and monitor pain in cancer patients are available, but few head-to-head psychometric comparisons of different measures have been reported. Baseline and 3-month data were analyzed from 274 patients enrolled in the Indiana Cancer Pain and Depression (INCPAD) trial. Participants completed the Brief Pain Inventory (BPI), the PEG (a 3-item abbreviated version of the BPI), the short form (SF)-36 pain scale, and a pain global rating of change measure. The global rating was used as the criterion for standardized response mean and receiver operating characteristic curve analyses. To assess responsiveness to the trial intervention, we evaluated standardized effect size statistics stratified by trial arm. All measures were responsive to global improvement, discriminated between participants with and without improvement, and detected a significant intervention treatment effect. Short and longer measures were similarly responsive. Also, composite measures that combined pain severity and interference into a single score (BPI total, PEG, SF-36 pain) performed comparably to separate measures of each domain (BPI severity and BPI interference).
Pain measures as brief as 2 or 3 items that provide a single score are responsive in patients with cancer-related pain. Ultra-brief measures offer a valid and efficient means of assessing and monitoring pain for the clinical management as well as research of cancer-related pain.
PMCID: PMC4269348  PMID: 22800982
Cancer; pain; measures; assessment; diagnosis; psychometrics
2.  Measuring adherence to antiretroviral therapy in children and adolescents in western Kenya 
High levels of adherence to antiretroviral therapy (ART) are central to HIV management. The objective of this study was to compare multiple measures of adherence and investigate factors associated with adherence among HIV-infected children in western Kenya.
We evaluated ART adherence prospectively for six months among HIV-infected children aged ≤14 years attending a large outpatient HIV clinic in Kenya. Adherence was reported using caregiver report, plasma drug concentrations and Medication Event Monitoring Systems (MEMS®). Kappa statistics were used to compare adherence estimates with MEMS®. Logistic regression analyses were performed to assess the association between child, caregiver and household characteristics with dichotomized adherence (MEMS® adherence ≥90% vs. <90%) and MEMS® treatment interruptions of ≥48 hours. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.
Among 191 children, mean age at baseline was 8.2 years and 55% were female. Median adherence by MEMS® was 96.3% and improved over the course of follow-up (p<0.01), although 49.5% of children had at least one MEMS® treatment interruption of ≥48 hours. Adherence estimates were highest by caregiver report, and there was poor agreement between MEMS® and other adherence measures (Kappa statistics 0.04–0.37). In multivariable logistic regression, only caregiver-reported missed doses in the past 30 days (OR 1.25, 95% CI 1.14–1.39), late doses in the past seven days (OR 1.14, 95% CI 1.05–1.22) and caregiver-reported problems with getting the child to take ART (OR 1.10, 95% CI 1.01–1.20) were significantly associated with dichotomized MEMS® adherence. The caregivers reporting that ART made the child sick (OR 1.12, 95% CI 1.01–1.25) and reporting difficulties in the community that made giving ART more difficult (e.g. stigma) (OR 1.14, 95% CI 1.02–1.27) were significantly associated with MEMS® treatment interruptions in multivariable logistic regression.
Non-adherence in the form of missed and late doses, treatment interruptions of more than 48 hours and sub-therapeutic drug levels were common in this cohort. Adherence varied significantly by adherence measure, suggesting that additional validation of adherence measures is needed. Few factors were consistently associated with non-adherence or treatment interruptions.
PMCID: PMC4245448  PMID: 25427633
adherence; paediatric HIV; best practice; resource-limited setting
3.  Association of Chlamydia trachomatis Infection With Redetection of Human Papillomavirus After Apparent Clearance 
The Journal of Infectious Diseases  2013;208(9):1416-1421.
Background. Persistent infection with oncogenic human papillomavirus (HPV) is associated with an increased risk of cervical malignancy. Redetection of type-specific HPV after a period of nondetection may be caused by reactivation of a low-level persistent infection. Little is known about factors associated with type-specific HPV redetection.
Methods. For a longitudinal cohort of adolescent women with frequent behavioral and sexually transmitted infection (STI) information (every 3 months), Cox proportional hazard models were used to assess the influence of sexual behaviors and STIs on the redetection of oncogenic or high-risk HPV infections.
Results. A total of 210 type-specific high-risk HPV detection episode periods were identified in this longitudinal cohort; 71 (33.8%) were characterized by a period of nondetection followed by redetection. Chlamydia trachomatis (hazard ratio [HR], 3.14; 95% confidence interval [CI], 1.44–6.86) was associated with redetection; redetection was >2 times more likely with each additional self-reported sex partner in the past 3 months (HR, 2.26; 95% CI, 1.35–3.78).
Conclusions. This study demonstrates the role of C. trachomatis and number of recent sexual partners in type-specific HPV redetection. Given that persistent oncogenic HPV infections are associated with cancer-related outcomes, understanding the potential role of such factors in the pathogenesis of HPV-related outcomes is important.
PMCID: PMC3789572  PMID: 23911713
human papillomavirus; chlamydia; HPV redetection
4.  Adiposity has Unique Influence on the Renin-Aldosterone Axis and Blood Pressure in Black Children 
The Journal of pediatrics  2013;163(5):10.1016/j.jpeds.2013.06.082.
To comparatively examine the effects of adiposity on the levels of plasma renin activity (PRA), plasma aldosterone concentrations (PAC), and aldosterone-renin ratios (ARR) in young black and white children.
Study design
We prospectively assessed 248 black and 345 white children and adolescents. A novel analytical technique was used to assess the concurrent influences of age and body mass index (BMI) on PRA, PAC, and ARR. The estimated effects were depicted by colored contour plots.
In contrast to whites, blacks had lower PRA (2.76 vs 3.36 ng/ml/h; p<0.001) and lower PAC (9.01 vs 14.59 ng/dl; p<0.001). In blacks, BMI was negatively associated with PRA (p=0.001), consistent with an association with a more expanded plasma volume; there was no association with PAC. In whites, BMI was positively associated with PAC (p=0.005); we did not detect a BMI-PRA association. The effects of BMI on ARR were directionally similar in the two race groups but more pronounced in blacks. Mean systolic BP was greater in blacks with lower PRA (p<0.01), higher PAC (p=0.015), and higher ARR (p=0.49).
An increase in adiposity was associated with a suppressed PRA in blacks and an increase in PAC in whites. The unique relationship between adiposity and renin-aldosterone axis in blacks suggests the possible existence of a population-specific mechanism characterized by volume expansion, which could in turn enhance the influences of adiposity on BP in black children and adolescents.
PMCID: PMC3812413  PMID: 23941668
Adolescent; hypertension; obesity
5.  Hospital and Nursing Home Use from 2002 to 2008 among U.S. Older Adults with Cognitive Impairment, Not dementia in 2002 
Alzheimer disease and associated disorders  2013;27(4):10.1097/WAD.0b013e318276994e.
Little is known about health care use in the cognitive impairment, not dementia (CIND) subpopulation. Using a cohort of 7,130 persons aged 71 years or over from the Health and Retirement Survey we compared mean and total health care use from 2002–2008 for those with no cognitive impairment [CI], CIND, or dementia in 2002.
Cognitive status was determined using a validated method based on self or proxy interview measures. Health care use was also based on self or proxy reports.
Based on the HRS, the CIND subpopulation in 2002 was 5.3 million; or 23% of the total population 71 years of age or over. Mean hospital nights was similar and mean nursing home nights was less in persons with CIND compared to persons with dementia. The CIND subpopulation, however, had more total hospital and nursing home nights; 71,000 total hospital nights and 223,000 total nursing home nights versus 32,000 hospital nights and 138,000 nursing home nights in the dementia subpopulation.
A relatively large population and high health care use result in a large health care impact of the CIND subpopulation.
PMCID: PMC3607633  PMID: 23151595
Older Adults; Cognitive Impairment; Health Services Use
6.  Impact of Dementia on Payments for Long-term and Acute Care in an Elderly Cohort 
Medical care  2013;51(7):575-581.
Older people with dementia have increased risk of nursing home (NH) use and higher Medicaid payments. Dementia’s impact on acute care use and Medicare payments is less well understood.
Identify trajectories of incident dementia and NH use, and (2) compare Medicare and Medicaid payments for persons having different trajectories.
Research Design
Retrospective cohort of older patients who were screened for dementia in 2000–2004 and were tracked for five years. Trajectories were identified with latent class growth analysis.
3673 low-income persons age 65 or older without dementia at baseline.
Incident dementia diagnosis, comorbid conditions, dual eligibility, acute and long-term care use and payments based on Medicare and Medicaid claims, medical record systems, and administrative data.
Three trajectories were identified based on dementia incidence and short and long-term NH use: (1) high incidence of dementia with heavy NH use (5% of the cohort) averaging $56,111/year ($36,361 Medicare, $19,749 Medicaid); (2) high incidence of dementia with little or no NH use (16% of the cohort) averaging $16,206/year ($14,644 Medicare, $1,562 Medicaid); and (3) low incidence of dementia and little or no NH use (79% of the cohort) averaging $8,475/year ($7,558 Medicare, $917 Medicaid).
Dementia and its interaction with NH utilization are major drivers of publicly financed acute and long-term care payments. Medical providers in accountable care organizations and other health care reform efforts must effectively manage dementia care across the care continuum if they are to be financially viable.
PMCID: PMC3680786  PMID: 23756644
dementia; nursing home; acute care; payment
7.  DNA Detection and Seroprevalence of Human Papillomavirus in a Cohort of Adolescent Women 
Human papillomavirus (HPV infections are common in adolescent females, while the rare cancerous sequelae of HPV infections do not generally occur until the 4th or 5th decades of life. This prospective study of a cohort of adolescent women was performed to further our knowledge of the natural history of incident and prevalent HPV infections.
Self-vaginal swabs collected from high-risk, unvaccinated adolescent women in a longitudinal study were analyzed for HPV DNA. Sera collected at enrollment and later were tested for HPV antibodies. Statistical analysis was performed to determine the HPV genotype distribution and duration of detection, and to determine rates of seropositivity and seroconversion for HPV types represented in the assays.
146 subjects (mean age = 15.4 years at enrollment; mean duration of follow-up = 5.8 years) had samples adequate for analysis of HPV detection, and 95 of these subjects had paired sera available. The cumulative prevalence for high-risk and low-risk HPV types was 95.9% and 91.1%, respectively. HPV types 6, 11, 16, and 18 (HPV types represented in the quadrivalent vaccine) were found at some point in 40.4%, 6.2%, 48%, and 24% of participants, respectively. Serologic data confirmed exposure to these vaccine-covered types, as well as to other high-risk HPV types.
In this cohort of adolescent women, high-risk and low-risk HPV types were frequently detected, and serologic data confirmed exposure in most subjects. The high prevalence HPV types represented in the quadrivalent HPV vaccine further supports vaccination of women at an age well before sexual debut.
PMCID: PMC4034260  PMID: 24031030
Human Papillomavirus; adolescents; antibodies; seroprevalence
8.  Estimating age-dependent per-encounter chlamydia trachomatis acquisition risk via a Markov-based state-transition model 
Chlamydial infection is a common bacterial sexually transmitted infection worldwide, caused by C. trachomatis. The screening for C. trachomatis has been proven to be successful. However, such success is not fully realized through tailoring the recommended screening strategies for different age groups. This is partly due to the knowledge gap in understanding how the infection is correlated with age. In this paper, we estimate age-dependent risks of acquiring C. trachomatis by adolescent women via unprotected heterosexual acts.
We develop a time-varying Markov state-transition model and compute the incidences of chlamydial infection at discrete age points by simulating the state-transition model with candidate per-encounter acquisition risks and sampled numbers of unit-time unprotected coital events at different age points. We solve an optimization problem to identify the age-dependent estimates that offer the closest matches to the observed infection incidences. We also investigate the impact of antimicrobial treatment effectiveness on the parameter estimates and the differences between the acquisition risks for the first-time infections and repeated infections.
Our case study supports the beliefs that age is an inverse predictor of C. trachomatis transmission and that protective immunity developed after initial infection is only partial.
Our modeling method offers a flexible and expandable platform for investigating STI transmission.
PMCID: PMC4022339  PMID: 24872872
Chlamydial infection; Acquisition risk; Transmission probability; Parameter estimation; State transition model
9.  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
10.  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
11.  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
12.  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
13.  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
14.  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
15.  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
17.  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
18.  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
19.  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
20.  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
21.  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
22.  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
23.  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
24.  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
25.  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

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