Biostatistics Commons^™

Adaptive Pair-Matching In The Search Trial And Estimation Of The Intervention Effect, Laura Balzer, Maya L. Petersen, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

In randomized trials, pair-matching is an intuitive design strategy to protect study validity and to potentially increase study power. In a common design, candidate units are identified, and their baseline characteristics used to create the best n/2 matched pairs. Within the resulting pairs, the intervention is randomized, and the outcomes measured at the end of follow-up. We consider this design to be adaptive, because the construction of the matched pairs depends on the baseline covariates of all candidate units. As consequence, the observed data cannot be considered as n/2 independent, identically distributed (i.i.d.) pairs of units, as current practice assumes. …

Concomitant Socioeconomic, Behavioral, And Biological Factors Associated With The Disproportionate Hiv Infection Burden Among Black Men Who Have Sex With Men In 6 U.S. Cities, Kenneth H. Mayer, Lei Wang, Beryl A. Koblin, Sharon B. Mannheimer, Manya Magnus, +13 Additional Authors

Epidemiology Faculty Publications

Background

American Black men who have sex with men (MSM) are disproportionately affected by HIV, but the factors associated with this concentrated epidemic are not fully understood.

Methods

Black MSM were enrolled in 6 US cities to evaluate a multi-component prevention intervention, with the current analysis focusing on the correlates of being newly diagnosed with HIV compared to being HIV-uninfected or previously diagnosed with HIV.

Results

HPTN 061 enrolled 1553 Black MSM whose median age was 40; 30% self-identified exclusively as gay or homosexual, 29% exclusively as bisexual, and 3% as transgender. About 1/6th(16.2%) were previously diagnosed with HIV (PD); …

Analysis Of Schizophrenia Data Using A Nonlinear Threshold Index Logistic Model., Zhenyu Jiang, Chengan Du, Assen Jablensky, Hua Liang, Zudi Lu, Yang Ma, Kok Lay Teo

GW Biostatistics Center

Genetic information, such as single nucleotide polymorphism (SNP) data, has been widely recognized as useful in prediction of disease risk. However, how to model the genetic data that is often categorical in disease class prediction is complex and challenging. In this paper, we propose a novel class of nonlinear threshold index logistic models to deal with the complex, nonlinear effects of categorical/discrete SNP covariates for Schizophrenia class prediction. A maximum likelihood methodology is suggested to estimate the unknown parameters in the models. Simulation studies demonstrate that the proposed methodology works viably well for moderate-size samples. The suggested approach is therefore …

Community Colleges And Public Health: An Integral Part Of The Continuum Of Education For Public Health, Richard Riegelman, Cynthia Wilson

Epidemiology Faculty Publications

No abstract provided.

Causal Models And Learning From Data: Integrating Causal Modeling And Statistical Estimation, Maya Petersen, M J. Van Der Laan

Maya Petersen

No abstract provided.

Hiv Testing Implementation In Two Urban Cities: Practice, Policy, And Perceived Barriers., Camden J Hallmark, Jennifer Skillicorn, Thomas P Giordano, Jessica A Davila, Marlene Mcneese, Nestor Rocha, Avemaria Smith, Stacey Cooper, Amanda D. Castel

Epidemiology Faculty Publications

BACKGROUND: Although funding has supported the scale up of routine, opt-out HIV testing in the US, variance in implementation mechanisms and barriers in high-burden jurisdictions remains unknown.

METHODS: We conducted a survey of health care organizations in Washington, DC and Houston/Harris County to determine number of HIV tests completed in 2011, policy and practices associated with HIV testing, funding mechanisms, and reported barriers to testing in each jurisdiction and to compare results between jurisdictions.

RESULTS: In 2012, 43 Houston and 35 DC HIV-testing organizations participated in the survey. Participants represented 85% of Department of Health-supported testers in DC and 90% …

Short And Long-Term Lifestyle Coaching Approaches Used To Address Diverse Participant Barriers To Weight Loss And Physical Activity Adherence, Elizabeth M. Venditti, Judith Wylie-Rosett, Linda M. Delahanty, Lisa L. Mele, Mary A. Hoskin, Sharon Edelstein

GW Biostatistics Center

Background

Individual barriers to weight loss and physical activity goals in the Diabetes Prevention Program, a randomized trial with 3.2 years average treatment duration, have not been previously reported. Evaluating barriers and the lifestyle coaching approaches used to improve adherence in a large, diverse participant cohort can inform dissemination efforts.

Methods

Lifestyle coaches documented barriers and approaches after each session (mean session attendance = 50.3 +/- 21.8). Subjects were 1076 intensive lifestyle participants (mean age = 50.6 years; mean BMI = 33.9 kg/m2; 68% female, 48% non-Caucasian). Barriers and approaches used to improve adherence were ranked by the percentage of …

Engagement With Care, Substance Use, And Adherence To Therapy In Hiv/Aids, Patrice K. Nicholas, Suzanne Willard, Clinton J. Thompson, Carol Dawson-Rose, Inge B. Corless, +20 Additional Authors

GW Biostatistics Center

Engagement with care for those living with HIV is aimed at establishing a strong relationship between patients and their health care provider and is often associated with greater adherence to therapy and treatment (Flickinger, Saha, Moore, and Beach, 2013). Substance use behaviors are linked with lower rates of engagement with care and medication adherence (Horvath, Carrico, Simoni, Boyer, Amico, and Petroli, 2013). This study is a secondary data analysis using a cross-sectional design from a larger randomized controlled trial (n = 775) that investigated the efficacy of a self-care symptom management manual for participants living with HIV. Participants were …

Cardiometabolic Risk Assessments By Body Mass Index Z-Score Or Waist-To-Height Ratio In A Multiethnic Sample Of Sixth-Graders, Henry S. Kahn, Laure El Ghormli, Russell Jago, Gary D. Foster, Robert G. Mcmurray, John B. Buse, Diane D. Stadler, Roberto P. Trevino, Tom Baranowski, Healthy Study Group

GW Biostatistics Center

Convention defines pediatric adiposity by the body mass index -score (BMIz) referenced to normative growth charts. Waist-to-height ratio (WHtR) does not depend on sex-and-age references. In the HEALTHY Study enrollment sample, we compared BMIz with WHtR for ability to identify adverse cardiometabolic risk. Among 5,482 sixth-grade students from 42 middle schools, we estimated explanatory variations (R²) and standardized beta coefficients of BMIz or WHtR for cardiometabolic risk factors: insulin resistance (HOMA-IR), lipids, blood pressures, and glucose. For each risk outcome variable, we prepared adjusted regression models for four subpopulations stratified by sex and high versus lower fatness. …

Mediation Analysis Of Gestational Age, Congenital Heart Defects, And Infant Birth-Weight, Adane Wogu, Christopher Loffredo, Ionut Bebu, George Luta

GW Biostatistics Center

Background

In this study we assessed the mediation role of the gestational age on the effect of the infant’s congenital heart defects (CHD) on birth-weight.

Methods

We used secondary data from the Baltimore-Washington Infant Study (1981–1989). Mediation analysis was employed to investigate whether gestational age acted as a mediator of the association between CHD and reduced birth-weight. We estimated the mediated effect, the mediation proportion, and their corresponding 95% confidence intervals (CI) using several methods.

Results

There were 3362 CHD cases and 3564 controls in the dataset with mean birth-weight of 3071 (SD = 729) and 3353 (SD = 603) …

Estimating Population Treatment Effects From A Survey Sub-Sample, Kara E. Rudolph, Ivan Diaz, Michael Rosenblum, Elizabeth A. Stuart

Johns Hopkins University, Dept. of Biostatistics Working Papers

We consider the problem of estimating an average treatment effect for a target population from a survey sub-sample. Our motivating example is generalizing a treatment effect estimated in a sub-sample of the National Comorbidity Survey Replication Adolescent Supplement to the population of U.S. adolescents. To address this problem, we evaluate easy-to-implement methods that account for both non-random treatment assignment and a non-random two-stage selection mechanism. We compare the performance of a Horvitz-Thompson estimator using inverse probability weighting (IPW) and two double robust estimators in a variety of scenarios. We demonstrate that the two double robust estimators generally outperform IPW in …

Spatial Epidemiology And Climatic Predictors Of Paediatric Dengue Infections Captured Via Sentinel Site Surveillance, Phnom Penh Cambodia 2011–2012, Andrew A. Lover, Philippe Buchy, Anne Rachline, Duch Moniboth, Rekol Huy, Chour Y. Meng, Yee Sin Leo, Kdan Yuvatha, Ung Sophal, Ngan Chantha, Bunthin Y, Veasna Duong, Sophie Goyet, Jeremy Brett, Arnaud Tarantola, Philippe Cavailler

Andrew Lover

Retention And Risk Factors For Attrition In A Large Public Health Art Program In Myanmar: A Retrospective Cohort Analysis, Aye Thida, Sai Thein Than Tun, Sai Ko Ko Zaw, Andrew A. Lover, Philippe Cavailler, Jennifer Chunn, Mar Mar Aye, Par Par, Kyaw Win Naing, Kaung Nyunt Zan, Myint Shwe Shwe, Thar Tun Kyaw, Zaw Htoon Waing, Philippe Clevenbergh

Andrew Lover

Note On The Origin Of The Madagascar Strain Of Plasmodium Vivax, Andrew A. Lover

Andrew Lover

Demographic And Spatial Predictors Of Anemia In Women Of Reproductive Age In Timor-Leste: Implications For Health Program Prioritization, Andrew A. Lover, Mikael Hartman, Kee Seng Chia, David L. Heymann

Andrew Lover

The Distribution Of Incubation And Relapse Times In Experimental Human Infections With The Malaria Parasite Plasmodium Vivax, Andrew A. Lover, Xiahong Zhao, Zheng Gao, Richard J. Coker, Alex R. Cook

Andrew Lover