Biostatistics Commons^™

Study On Clinical, Histopathological Features And Evaluation Results Of Skin Cancer Treatment In Can Tho Oncology Hospital, Nguyen Van Qui, Phan Nguyen Ngoc

Kesmas

Kanker kulit, diagnosis kanker paling umum, cenderung mengalami peningkatan. Kondisi ini secara khusus merupakan isu penting di negara-negara maju. Penelitian ini bertujuan untuk mendeskripsikan fitur klinis, fitur hispatologis, komplikasi dan hasil pengobatan bedah awal kanker kulit di Rumah Sakit Onkologi Can Tho dari tahun 2014 sampai 2015. Penelitian deskriptif prospektif ini melibatkan seluruh pasien dengan kanker kulit nonmelanoma yang diuji dan diobati di Rumah Sakit Onkologi Can Tho dari Juli 2014 sampai Maret 2015. Terdapat 78 kasus terpilih. Kanker kulit ditemukan lebih umum pada pasien yang lebih tua. Prevalensi karsinoma sel basal ditemukan lebih tinggi dibandingkan karsinoma sel skuamosa dengan …

Communication Of Parents, Sexual Content Intake And Teenage Sexual Behavior At Senior High School In Banjarmasin City, Rusmilawaty Rusmilawaty, Yuniarti Yuniarti, Tri Tunggal

Kesmas

Perilaku seks bebas di kalangan remaja Kota Banjarmasin belakangan ini semakin mengkhawatirkan para orangtua. Kurangnya pendidikan seksologi berdampak para remaja cenderung melakukan hubungan seksual pranikah yang akan berakibat pada kehamilan yang tidak diinginkan dan pernikahan dini. Komunikasi orangtua-anak dan paparan media baik media cetak maupun elektronik merupakan cara untuk mengurangi perilaku seksual berisiko. Tujuan penelitian ini untuk mengetahui hubungan komunikasi orangtua dan asupan muatan seksual dengan perilaku seksual remaja sekolah menengah atas (SMA) di Kota Banjarmasin. Untuk mencapai tujuan tersebut, penelitian survei analitik dengan pendekatan potong lintang dilakukan pada bulan Juli – Oktober 2015 di dua sekolah negeri dan satu …

Crtgeedr: An R Package For Doubly Robust Generalized Estimating Equations Estimations In Cluster Randomized Trials With Missing Data, Melanie Prague, Rui Wang, Victor De Gruttola

Harvard University Biostatistics Working Paper Series

No abstract provided.

Statistical Interpretation Including The Appropriate Statistical Tests, Olga A. Vsevolozhskaya

Biostatistics Presentations

Outline:

1. Evaluation of treatment’s therapeutic potential after experimental stroke.
2. Post-stroke behavioral testing and functional recovery.

Alzheimer's Biomarkers Are Correlated With Brain Connectivity In Older Adults Differentially During Resting And Task States, Yang Jiang, Haiqing Huang, Erin Abner, Lucas S. Broster, Gregory A. Jicha, Frederick A. Schmitt, Richard Kryscio, Anders H. Andersen, David Powell, Linda J. Van Eldik, Brian T. Gold, Peter T. Nelson, Charles D. Smith, Mingzhou Ding

Behavioral Science Faculty Publications

β-amyloid (Aβ) plaques and tau-related neurodegeneration are pathologic hallmarks of Alzheimer’s disease (AD). The utility of AD biomarkers, including those measured in cerebrospinal fluid (CSF), in predicting future AD risk and cognitive decline is still being refined. Here, we explored potential relationships between functional connectivity (FC) patterns within the default-mode network (DMN), age, CSF biomarkers (Aβ₄₂ and pTau₁₈₁), and cognitive status in older adults. Multiple measures of FC were explored, including a novel time series-based measure [total interdependence (TI)]. In our sample of 27 cognitively normal older adults, no significant associations were found between levels of Aβ …

Hpcnmf: A High-Performance Toolbox For Non-Negative Matrix Factorization, Karthik Devarajan, Guoli Wang

COBRA Preprint Series

Non-negative matrix factorization (NMF) is a widely used machine learning algorithm for dimension reduction of large-scale data. It has found successful applications in a variety of fields such as computational biology, neuroscience, natural language processing, information retrieval, image processing and speech recognition. In bioinformatics, for example, it has been used to extract patterns and profiles from genomic and text-mining data as well as in protein sequence and structure analysis. While the scientific performance of NMF is very promising in dealing with high dimensional data sets and complex data structures, its computational cost is high and sometimes could be critical for …

A Test Of Symmetry Based On The Kernel Kullback-Leibler Information With Application To Base Deficit Data, Hani M. Samawi, Robert L. Vogel

Biostatistics: Faculty Publications

The assumption of the symmetry of the underlying distribution is important to many statistical inference and modeling procedures. This paper provides a test of symmetry using kernel density estimation and the Kullback-Leibler information. Based on simulation studies, the new test procedure outperforms other tests of symmetry found in the literature, including the Runs Test of Symmetry. We illustrate our new procedure using real data.

Accounting For Interactions And Complex Inter-Subject Dependency In Estimating Treatment Effect In Cluster Randomized Trials With Missing Outcomes, Melanie Prague, Rui Wang, Alisa Stephens, Eric Tchetgen Tchetgen, Victor Degruttola

Harvard University Biostatistics Working Paper Series

No abstract provided.

Models For Hsv Shedding Must Account For Two Levels Of Overdispersion, Amalia Magaret

UW Biostatistics Working Paper Series

We have frequently implemented crossover studies to evaluate new therapeutic interventions for genital herpes simplex virus infection. The outcome measured to assess the efficacy of interventions on herpes disease severity is the viral shedding rate, defined as the frequency of detection of HSV on the genital skin and mucosa. We performed a simulation study to ascertain whether our standard model, which we have used previously, was appropriately considering all the necessary features of the shedding data to provide correct inference. We simulated shedding data under our standard, validated assumptions and assessed the ability of 5 different models to reproduce the …

An Efficient Basket Trial Design, Kristen Cunanan, Alexia Iasonos, Ronglai Shen, Colin B. Begg, Mithat Gonen

Memorial Sloan-Kettering Cancer Center, Dept. of Epidemiology & Biostatistics Working Paper Series

The landscape for early phase cancer clinical trials is changing dramatically due to the advent of targeted therapy. Increasingly, new drugs are designed to work against a target such as the presence of a specific tumor mutation. Since typically only a small proportion of cancer patients will possess the mutational target, but the mutation is present in many different cancers, a new class of basket trials is emerging, whereby the drug is tested simultaneously in different baskets, i.e., sub-groups of different tumor types. Investigators not only desire to test whether the drug works, but also to determine which types of …

Variable Selection For Case-Cohort Studies With Failure Time Outcome, Andy Ni, Jianwen Cai, Donglin Zeng

Memorial Sloan-Kettering Cancer Center, Dept. of Epidemiology & Biostatistics Working Paper Series

Case-cohort designs are widely used in large cohort studies to reduce the cost associated with covariate measurement. In many such studies the number of covariates is very large, so an efficient variable selection method is necessary. In this paper, we study the properties of variable selection using the smoothly clipped absolute deviation penalty in a case-cohort design with a diverging number of parameters. We establish the consistency and asymptotic normality of the maximum penalized pseudo-partial likelihood estimator, and show that the proposed variable selection procedure is consistent and has an asymptotic oracle property. Simulation studies compare the finite sample performance …

Leveraging Contact Network Structure In The Design Of Cluster Randomized Trials, Guy Harling, Rui Wang, Jukka-Pekka Onnela, Victor Degruttola

Harvard University Biostatistics Working Paper Series

Background: In settings like the Ebola epidemic, where proof-of-principle trials have succeeded but questions remain about the effectiveness of different possible modes of implementation, it may be useful to develop trials that not only generate information about intervention effects but also themselves provide public health benefit. Cluster randomized trials are of particular value for infectious disease prevention research by virtue of their ability to capture both direct and indirect effects of intervention; the latter of which depends heavily on the nature of contact networks within and across clusters. By leveraging information about these networks – in particular the degree …

Using Validation Data To Adjust The Inverse Probability Weighting Estimator For Misclassified Treatment, Danielle Braun, Corwin Zigler, Francesca Dominici, Malka Gorfine

Harvard University Biostatistics Working Paper Series

The inverse probability weighting (IPW) estimator is widely used to estimate the treatment effect in observational studies in which patient characteristics might not be balanced by treatment group. The estimator assumes that treatment assignment, is error-free, but in reality treatment assignment can be measured with error. This arises in the context of comparative effectiveness research, using administrative data sources in which accurate procedural or billing codes are not always available. We show the bias introduced to the estimator when using error-prone treatment assignment, and propose an adjusted estimator using a validation study to eliminate this bias. In simulations, we explore …

Estimation And Inference For The Mediation Proportion, Daniel Nevo, Xiaomei Liao, Donna Spiegelman

Harvard University Biostatistics Working Paper Series

In epidemiology, public health and social science, mediation analysis is often undertaken to investigate the extent to which the effect of a risk factor on an outcome of interest is mediated by other covariates. A pivotal quantity of interest in such an analysis is the mediation proportion. A common method for estimating it, termed the "difference method'', compares estimates from models with and without the hypothesized mediator. However, rigorous methodology for estimation and statistical inference for this quantity has not previously been available. We formulated the problem for the Cox model and generalized linear models, and utilize a data duplication …

A Cautionary Note On The Effect Of Treatment Misclassification On The Average Treatment Effect, Danielle Braun, Corwin Zigler, Malka Gorfine, Francesca Dominici

Harvard University Biostatistics Working Paper Series

Comparative effectiveness research often relies on large administrative data, such as claims data. Methods to estimate treatment effects assume that treatment assignment is error-free, but in reality the inaccuracy of procedural or billing codes frequently misclassifies patients into treatment groups. Propensity score methods are widely used to analyze observational studies in which patient characteristics might not be balanced by treatment group. We evaluate the impact of treatment misclassification on 1) propensity score estimation; 2) treatment effect estimation conditional on propensity score estimation and implementation. We focus on three common propensity score implementations: subclassification, matching, and inverse probability of treatment weighting …

The Myth Of Making Inferences For An Overall Treatment Efficacy With Data From Multiple Comparative Studies Via Meta-Analysis, Takahiro Hasegawa, Brian Claggett, Lu Tian, Scott D. Solomon, Marc A. Pfeffer, Lee-Jen Wei

Harvard University Biostatistics Working Paper Series

Meta analysis techniques, if applied appropriately, can provide a summary of the totality of evidence regarding an overall difference between a new treatment and a control group using data from multiple comparative clinical studies. The standard meta analysis procedures, however, may not give a meaningful between-group difference summary measure or identify a meaningful patient population of interest, especially when the fixed effect model assumption is not met. Moreover, a single between-group comparison measure without a reference value obtained from patients in the control arm would likely not be informative enough for clinical decision making. In this paper, we propose a …

Moving Beyond The Conventional Stratified Analysis To Estimate An Overall Treatment Efficacy With The Data From A Comparative Randomized Clinical Study, Lu Tian, Fei Jiang, Takahiro Hasegawa, Hajime Uno, Marc Alan Pfeffer, L.J. Wei

Harvard University Biostatistics Working Paper Series

No abstract provided.

Detectable Viral Load In Late Pregnancy Among Women In The Rwanda Option B+ Pmtct Program: Enrollment Results From The Kabeho Study., Michelle M Gill, Heather J Hoffman, Emily A Bobrow, Placidie Mugwaneza, Dieudonne Ndatimana, Gilles F Ndayisaba, Cyprien Baribwira, Laura Guay, Anita Asiimwe

Epidemiology Faculty Publications

There are limited viral load (VL) data available from programs implementing "Option B+," lifelong antiretroviral treatment (ART) to all HIV-positive pregnant and postpartum women, in resource-limited settings. Extent of viral suppression from a prevention of mother-to-child transmission of HIV program in Rwanda was assessed among women enrolled in the Kigali Antiretroviral and Breastfeeding Assessment for the Elimination of HIV (Kabeho) Study. ARV drug resistance testing was conducted on women with VL>2000 copies/ml. In April 2013-January 2014, 608 pregnant or early postpartum HIV-positive women were enrolled in 14 facilities. Factors associated with detectable enrollment VL (>20 copies/ml) were examined …

Male Pattern Baldness In Relation To Prostate Cancer–Specific Mortality: A Prospective Analysis In The Nhanes I Epidemiologic Follow-Up Study, Cindy Ke Zhou, Paul H Levine, Sean D. Cleary, Heather J. Hoffman, Barry I Graubard, Michael B. Cook

Epidemiology Faculty Publications

We used male pattern baldness as a proxy for long-term androgen exposure and investigated the association of dermatologist-assessed hair loss with prostate cancer–specific mortality in the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. From the baseline survey (1971–1974), we included 4,316 men who were 25–74 years of age and had no prior cancer diagnosis. We estimated hazard ratios and used Cox proportional hazards regressions with age as the time metric and baseline hazard stratified by baseline age. A hybrid framework was used to account for stratification and clustering of the sample design, with adjustment for the variables …

Socioecological Factors Influencing Women's Hiv Risk In The United States: Qualitative Findings From The Women's Hiv Seroincidence Study (Hptn 064)., Paula M Frew, Kimberly Parker, Linda Vo, Danielle Haley, Ann O'Leary, Dazon Dixon Diallo, Carol E Golin, Irene Kuo, Lydia Soto-Torres, Jing Wang, Adaora A Adimora, Laura A Randall, Carlos Del Rio, Sally Hodder, Hiv Prevention Trials Network 064 (Htpn) Study Team.

Epidemiology Faculty Publications

BACKGROUND: We sought to understand the multilevel syndemic factors that are concurrently contributing to the HIV epidemic among women living in the US. We specifically examined community, network, dyadic, and individual factors to explain HIV vulnerability within a socioecological framework.

METHODS: We gathered qualitative data (120 interviews and 31 focus groups) from a subset of women ages 18-44 years (N = 2,099) enrolled in the HPTN 064 HIV seroincidence estimation study across 10 US communities. We analyzed data from 4 diverse locations: Atlanta, New York City (the Bronx), Raleigh, and Washington, DC. Data were thematically coded using grounded theory methodology. …