Biostatistics Commons^™

Dealing With Zero-Numerators In Estimating Drug-Dependence Chances: A Bayesian Approach, Olga A. Vsevolozhskaya, Fernando A. Wagner, James C. Anthony

Biostatistics Presentations

Aims: At CPDD 2015, we applied parametric Hill functions to estimate the probability of drug dependence in relation to the duration of drug-taking experience. A problem we and others have encountered in the estimation of risk of becoming a drug dependence case is an observed point estimate of zero – the so-called “zero-numerator problem.” This problem can be easily observed in certain low risk subgroups even when the sample is large (e.g., the incidence of heroin dependence among 12 year old newly incident heroin users) or with small subgroup sample sizes. In these instances, tan observed zero point estimate …

Mapping Morels: Predicting The Locations Of Morchella Species Through Environmental Factors Using The Gis System, Emily M. Stanevicius

Celebration of Learning

Morel mushrooms, Morechella esculenta and M. deliciosa, are known delicacies across the globe, ranging from exquisite dishes in French cuisine to Eastern palates such as Japanese Matsutake. According to literature, true morels diverged as their own genus about 129 million years, again which has led to the development of more than 177 species and have been part of the human diet since their beginning. However, the elusiveness of morels has contributed to the mushrooms infamy for rarity, and has even been known to sell for more than $40 per pound. This project seeks to aid in the search for morels …

Putting Prep Into Practice: Lessons Learned From Early-Adopting U.S. Providers' Firsthand Experiences Providing Hiv Pre-Exposure Prophylaxis And Associated Care, S. K. Calabrese, Manya Magnus, K. H. Mayer, D. S. Krakower, A. I. Eldahan, L. A. Gaston Hawkins, +5 Additional Authors

Epidemiology Faculty Publications

Optimizing access to HIV pre-exposure prophylaxis (PrEP), an evidence-based HIV prevention resource, requires expanding healthcare providers' adoption of PrEP into clinical practice. This qualitative study explored PrEP providers' firsthand experiences relative to six commonly-cited barriers to prescription-financial coverage, implementation logistics, eligibility determination, adherence concerns, side effects, and anticipated behavior change (risk compensation)-as well as their recommendations for training PrEP-inexperienced providers. U.S.-based PrEP providers were recruited via direct outreach and referral from colleagues and other participants (2014-2015). One-on-one interviews were conducted in person or by phone, transcribed, and analyzed. The sample (n = 18) primarily practiced in the Northeastern (67%) or …

Partner Interfering Behaviors Affecting Cancer Quality Of Life, Ann L. Coker, Diane R. Follingstad, Lisandra S. Garcia, Heather M. Bush

Obstetrics and Gynecology Faculty Publications

Objective: Because partners are an important and unpaid resource in cancer care, understanding how destructive, controlling or interfering partner behaviors influence women's cancer care may be particularly relevant for health care providers seeking to provide cancer care and enhance recovery. Using a new measure of partner interfering behaviors in cancer care (PIB-C), we investigated whether women with a recent cancer diagnosis who additionally endorsed any PIB-C would report (a) more symptoms of depression and stress, and (b) lower Functional Assessment of Cancer Therapy (FACT-G) and lower Functional Assessment of Chronic Illness Therapy-Spiritual Well-being (FACIT-SP) scale scores indicating poorer quality of …

Effect Of Ambient Particulate Matter 2.5 Micrometer (Pm2.5) To Prevalence Of Impaired Lung Function And Asthma In Tangerang And Makassar, Budi Haryanto, Budy Resosoedarmo, Sri Tjahjani Budi Utami, Budi Hartono, Ema Hermawati

Kesmas

Emisi partikel debu 2,5 mikrometer (PM2.5) meningkat dengan bertambahnya jumlah penduduk kota akibat peningkatan angka kendaraan bermotor sebagai transportasi penduduk sehari-hari. Penelitian ini bertujuan untuk mengetahui tingkat gangguan fungsi paru dan asma serta hubungannya dengan kadar ambien PM2.5 pada masyarakat migran di Tangerang dan Makassar dan kondisi sosial ekonomi. Desain potong lintang digunakan dengan melibatkan 4.250 dan 2.900 responden di Tangerang dan Makassar pada bulan April sampai September 2010. Pendekatan cluster sampling diterapkan. Pengukuran ambien PM2.5 di masing-masing kota berdasarkan koordinat 40 lokasi Global Positioning System (GPS). Kadar PM2.5 ditemukan lebih tinggi pada pagi hari dibandingkan siang hari di kedua …

Birth Intervals Among Multiparous Women In Indonesia, Dini Kurniawati, Sabarinah Prasetyo

Kesmas

Angka kematian ibu dan angka kematian bayi di Indonesia masih tinggi. Salah satu faktor yang menyebabkan tingginya risiko kematian pada ibu dan bayi adalah kelahiran terlalu dekat. Penelitian ini bertujuan untuk mempelajari determinan jarak antarkelahiran pada perempuan multipara di Indonesia. Penelitian ini menggunakan data Survei Demografi Kesehatan Indonesia tahun 2012 pada 9.945 perempuan multipara. Analisis data menggunakan uji Mann Whitney, Kruskal Wallis, dan regresi logistik. Median jarak antarkelahiran sebesar 62 bulan dan 22,8% perempuan memiliki jarak antarkelahiran kurang dari tiga tahun. Hasil menunjukkan determinan jarak antarkelahiran pendek meliputi pendidikan ibu, usia terakhir melahirkan, ukuran ideal keluarga, pemakaian kontrasepsi, riwayat kematian …

Child Health Improvement Through Implementation Of Food Safety Model, Arief Safari, Machfud Machfud, Eriyatno Eriyatno, Heny Kuswanti Daryanto

Kesmas

Pemenuhan akan pangan merupakan komponen dasar untuk mewujudkan sumber daya manusia yang berkualitas. Namun, masih terdapat permasalahan dalam mewujudkannya, di antaranya masalah keamanan pangan dengan persentase kasus keracunan makanan masih tinggi. Penelitian ini bertujuan untuk menganalisis situasi pelaksanaan keamanan Pangan Jajanan Anak Sekolah (PJAS) yang ada saat ini dan memilih alternatif model keamanan pangan yang paling efektif dan efisien diterapkan di usaha mikro kecil (UMK) guna meningkatkan keamanan pangan yang dihasilkannya sehingga terjadi peningkatan kesehatan anak. Penelitian dilakukan pada kuartal II tahun 2015 sampai dengan awal kuartal III tahun 2015 melalui survei lapangan dan survei pakar dengan mengambil studi kasus …

Housewives’ Compliance In Reading Food Labels In Gorontalo City, Imran Tumenggung, Lucky Herawati, Sofyawati Talibo

Kesmas

Di Indonesia, masalah label pada kemasan makanan kurang mendapat perhatian konsumen. Penelitian ini bertujuan untuk mempelajari determinan kepatuhan membaca label pada kemasan makanan oleh ibu rumah tangga di Kota Gorontalo. Penelitian dengan metode survei ini dilakukan dari bulan Juni sampai Agustus 2013. Data dikumpulkan secara potong lintang dengan menggunakan angket. Variabel terikat adalah kepatuhan membaca label pada kemasan makanan yang terdiri dari label informasi nilai gizi, komposisi makanan, masa kedaluwarsa, harga, dan status halal. Variabel bebas adalah usia, tingkat pendidikan, dan keterpaparan dengan media informasi. Besar sampel 262 orang ditentukan secara accidental technique. Analisis data menggunakan uji kai kuadrat. Hasil …

Husband’S Support Towards Unmet Need Of Hiv Positive-Infected Women Of Childbearing Age, Sophia Sophia, Anita Deborah Anwar, Bony Wiem Lestari

Kesmas

Jutaan wanita usia subur (WUS) dengan HIV positif di negara berkembang saat ini tidak menggunakan kontrasepsi untuk menunda atau mengakhiri kehamilan. Pencegahan kehamilan yang tidak diinginkan pada WUS dengan HIV positif sangat penting untuk meningkatkan kualitas hidup ibu dan anak. Tujuan penelitian ini untuk menganalisis faktor-faktor yang berpengaruh terhadap unmet need pada WUS dengan HIV positif. Metode penelitian adalah cross sectional dengan sampel berjumlah 130 WUS dengan HIV positif yang diambil secara consecutive sampling. Penelitian dilakukan pada 24 Maret - 30 Juni 2015 di Klinik Mawar Kota Bandung. Pengumpulan data dilakukan melalui wawancara dengan menggunakan kuesioner, kemudian data dianalisis dengan …

Impact Of Husband’S Participation In Antenatal Care On The Use Of Skilled Birth Attendant, Febri Wicaksono

Kesmas

Pendekatan alternatif diperlukan untuk mengatasi persoalan kesehatan reproduksi, salah satunya dengan meningkatkan partisipasi laki-laki pada kesehatan reproduksi perempuan. Penelitian ini bertujuan untuk menelusuri dampak partisipasi suami dalam pelayanan antenatal pada penggunaan tenaga persalinan terlatih setelah mengontrol karakteristik sosial demografi. Sampel sebanyak 4.000 perempuan berusia 15 – 49 tahun yang memiliki persalinan terakhir pada tahun lalu sebelum survei diambil dari Survei Demografi dan Kesehatan Indonesia tahun 2012. Penelitian menggunakan model regresi logistik biner untuk mengidentifikasi dampak partisipasi suami dalam pelayanan antenatal pada penggunaan tenaga persalinan terlatih setelah mengontrol karakteristik ibu dan sosial demografi. Peluang setelah mengontrol faktor lainnya mengindikasikan perempuan yang …

The Effect Of Structured Counseling Towards Knowledge, Attitude, And Participation Of Modern Contraceptive Among Unmet Need Couples, Herlina Simanjuntak, Bony Wiem Lestari, Anita Debora Anwar

Kesmas

Unmet need Keluarga Berencana (KB) masih tinggi di negara berkembang termasuk di Indonesia. Konseling kontrasepsi terstruktur berpotensi meningkatkan penggunaan kontrasepsi secara efektif, menjaga keberlangsungan penggunaan dan meningkatkan kepuasan klien. Selama ini seling kontrasepsi yang dilakukan belum optimal, sehingga penelitian ini bertujuan untuk menganalisis pengaruh konseling terstruktur terhadap peningkatan pengetahuan, sikap dan partisipasi kontrasepsi modern pada pasangan usia subur (PUS) yang unmet need. Penelitian ini merupakan eksperimen semu dengan rancangan pretest-posttest dengan kelompok kontrol. Penelitian ini dilakukan pada periode Maret – Juni 2015. Pengambilan sampel dilakukan dengan stratified random sampling pada 48 orang untuk kelompok perlakuan (konseling terstruktur) dan 48 orang …

Homeolog Specific Expression Bias, Ronald D. Smith

Biology and Medicine Through Mathematics Conference

No abstract provided.

Heterogeneous Responses To Viral Infection: Insights From Mathematical Modeling Of Yellow Fever Vaccine, James R. Moore

Biology and Medicine Through Mathematics Conference

No abstract provided.

Facets: Allele-Specific Copy Number And Clonal Heterogeneity Analysis Tool Estimates For High-Throughput Dna Sequencing, Ronglai Shen, Venkatraman Seshan

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

Allele-specific copy number analysis (ASCN) from next generation sequenc- ing (NGS) data can greatly extend the utility of NGS beyond the iden- tification of mutations to precisely annotate the genome for the detection of homozygous/heterozygous deletions, copy-neutral loss-of-heterozygosity (LOH), allele-specific gains/amplifications. In addition, as targeted gene panels are increasingly used in clinical sequencing studies for the detection of “actionable” mutations and copy number alterations to guide treatment decisions, accurate, tumor purity-, ploidy-, and clonal heterogeneity-adjusted integer copy number calls are greatly needed to more reliably interpret NGS- based cancer gene copy number data in the context of clinical sequencing. We …

Heart Failure Outcomes With Empagliflozin In Patients With Type 2 Diabetes At High Cardiovascular Risk: Results Of The Empa-Reg Outcome® Trial., David Fitchett, Bernard Zinman, Christoph Wanner, John M. Lachin, Stefan Hantel, Afshin Salsali, Odd Erik Johansen, Hans J Woerle, Uli C Broedl, Silvio E Inzucchi

Epidemiology Faculty Publications

AIMS: We previously reported that in the EMPA-REG OUTCOME(®) trial, empagliflozin added to standard of care reduced the risk of 3-point major adverse cardiovascular events, cardiovascular and all-cause death, and hospitalization for heart failure in patients with type 2 diabetes and high cardiovascular risk. We have now further investigated heart failure outcomes in all patients and in subgroups, including patients with or without baseline heart failure.

METHODS AND RESULTS: Patients were randomized to receive empagliflozin 10 mg, empagliflozin 25 mg, or placebo. Seven thousand and twenty patients were treated; 706 (10.1%) had heart failure at baseline. Heart failure hospitalization or …

Interpretable High-Dimensional Inference Via Score Maximization With An Application In Neuroimaging, Simon N. Vandekar, Philip T. Reiss, Russell T. Shinohara

UPenn Biostatistics Working Papers

In the fields of neuroimaging and genetics a key goal is testing the association of a single outcome with a very high-dimensional imaging or genetic variable. Oftentimes summary measures of the high-dimensional variable are created to sequentially test and localize the association with the outcome. In some cases, the results for summary measures are significant, but subsequent tests used to localize differences are underpowered and do not identify regions associated with the outcome. We propose a generalization of Rao's score test based on maximizing the score statistic in a linear subspace of the parameter space. If the test rejects the …

Population Projection And Habitat Preference Modeling Of The Endangered James Spinymussel (Pleurobema Collina), Marisa Draper

Senior Honors Projects, 2010-2019

The James Spinymussel (Pleurobema collina) is an endangered mussel species at the top of Virginia’s conservation list. The James Spinymussel plays a critical role in the environment by filtering and cleaning stream water while providing shelter and food for macroinvertebrates; however, conservation efforts are complicated by the mussels’ burrowing behavior, camouflage, and complex life cycle. The goals of the research conducted were to estimate detection probabilities that could be used to predict species presence and facilitate field work, and to track individually marked mussels to test for habitat preferences. Using existing literature and mark-recapture field data, these goals were accomplished …

Some Contributions To Nonparametric And Semiparametric Inference For Clustered And Multistate Data., Sandipan Dutta

Electronic Theses and Dissertations

This dissertation is composed of research projects that involve methods which can be broadly classified as either nonparametric or semiparametric. Chapter 1 provides an introduction of the problems addressed in these projects, a brief review of the related works that have done so far, and an outline of the methods developed in this dissertation. Chapter 2 describes in details the first project which aims at developing a rank-sum test for clustered data where an outcome from group in a cluster is associated with the number of observations belonging to that group in that cluster. Chapter 3 proposes the use of …

Identification Of Biomarkers For The Overall Survival Of Ovarian Cancer Patients, Kristi Mai

Graduate Theses and Dissertations

Rapid advance in sequencing technology has led to genome-wide analysis of genetic and epigenetic features simultaneously, making it possible to understand the biological mechanisms underlying cancer initiation and progression. However, how to identify important prognostic features poses a great challenge for both statistical modeling and computing. In this thesis, a network-based approach is applied to the Cancer Genome Atlas (TCGA) ovarian cancer data to identify important genes related to the overall survival of ovarian cancer patients. In the first step, a stepwise correlation-based selector is used to reduce the dimensionality of TCGA data, by filtering out a large number of …

Integration Of Multi-Platform High-Dimensional Omic Data, Xuebei An

Dissertations and Theses (Open Access)

The development of high-throughput biotechnologies have made data accessible from different platforms, including RNA sequencing, copy number variation, DNA methylation, protein lysate arrays, etc. The high-dimensional omic data derived from different technological platforms have been extensively used to facilitate comprehensive understanding of disease mechanisms and to determine personalized health treatments. Although vital to the progress of clinical research, the high dimensional multi-platform data impose new challenges for data analysis. Numerous studies have been proposed to integrate multi-platform omic data; however, few have efficiently and simultaneously addressed the problems that arise from high dimensionality and complex correlations.

In my dissertation, I …

A Log Rank Test For Clustered Data Under Informative Within-Cluster Group Size., Mary Elizabeth Gregg

Electronic Theses and Dissertations

The log rank test is a popular nonparametric test for comparing the marginal survival distribution of two groups. When data are organized within clusters and the size of clusters or the distribution of group membership within a cluster is related to an outcome of interest, traditional methods of data analysis can be biased. In this thesis, we develop a within-cluster group weighted log rank test to compare marginal survival time distributions between groups from clustered data, correcting for cluster size and intra-cluster group size informativeness. The performance of this new test is compared with the unweighted and cluster-weighted log rank …

Propensity Score Methods : A Simulation And Case Study Involving Breast Cancer Patients., John Craycroft

Electronic Theses and Dissertations

Observational data presents unique challenges for analysis that are not encountered with experimental data resulting from carefully designed randomized controlled trials. Selection bias and unbalanced treatment assignments can obscure estimations of treatment effects, making the process of causal inference from observational data highly problematic. In 1983, Paul Rosenbaum and Donald Rubin formalized an approach for analyzing observational data that adjusts treatment effect estimates for the set of non-treatment variables that are measured at baseline. The propensity score is the conditional probability of assignment to a treatment group given the covariates. Using this score, one may balance the covariates across treatment …

Semi-Parametric Methods For Personalized Treatment Selection And Multi-State Models., Chathura K. Siriwardhana

Electronic Theses and Dissertations

This dissertation contains three research projects on personalized medicine and a project on multi-state modelling. The idea behind personalized medicine is selecting the best treatment that maximizes interested clinical outcomes of an individual based on his or her genetic and genomic information. We propose a method for treatment assignment based on individual covariate information for a patient. Our method covers more than two treatments and it can be applied with a broad set of models and it has very desirable large sample properties. An empirical study using simulations and a real data analysis show the applicability of the proposed procedure. …

Inference For A Zero-Inflated Conway-Maxwell-Poisson Regression For Clustered Count Data., Hyoyoung Choo-Wosoba

Electronic Theses and Dissertations

This dissertation is directed toward developing a statistical methodology with applications of the Conway-Maxwell-Poisson (CMP) distribution (Conway, R. W., and Maxwell, W. L., 1962) to count data. The count data for this dissertation exhibit three different characteristics: clustering, zero inflation, and dispersion. Clustering suggests that observations within clusters are correlated, and the zero inflation phenomenon occurs when the data exhibit excessive zero counts. Dispersion implies that the mean is greater/smaller than the variance unlike a Poisson distribution. The dissertation starts with an introduction of inference for a zero-inflated clustered count data in the first chapter. Then, it presents novel methodologies …

Differences In Perceived Importance Of Preventative Services And Healthcare Provider Trust Among Hispanics, Jonathan James Gore

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Hispanic population varies greatly in their risk factors, health outcomes and access to care by country of origin, level of education and language dominance (Vega & Amaro, 1994) (Fiscella, Franks, Doescher, & Saver, 2002b). The differences within the Hispanic population also extend to their knowledge and attitudes toward health choices and maintenance, where they receive their health information, and what they access to meet their health care needs. Subpopulations within the Hispanic community as defined by language dominance and nativity must be understood as separate and distinct so that the health needs of each can be adequately addressed. The …

Methods For Dealing With Death And Missing Data, And For Standardizing Different Health Variables In Longitudinal Datasets: The Cardiovascular Health Study, Paula Diehr

UW Biostatistics Working Paper Series

Longitudinal studies of older adults usually need to account for deaths and missing data. The study databases often include multiple health-related variables, whose trends over time are hard to compare because they were measured on different scales. Here we present a unified approach to these three problems that was developed and used in the Cardiovascular Health Study. Data were first transformed to a new scale that had integer/ratio properties, and on which “dead” logically takes the value zero. Missing data were then imputed on this new scale, using each person’s own data over time. Imputation could thus be informed by …

Power And Sample Size Calculations For Interval-Censored Survival Analysis, Hae-Young Kim, John M. Williamson, Hung-Mo Lin

NYMC Faculty Publications

We propose a method for calculating power and sample size for studies involving interval-censored failure time data that only involves standard software required for fitting the appropriate parametric survival model. We use the framework of a longitudinal study where patients are assessed periodically for a response and the only resultant information available to the investigators is the failure window: the time between the last negative and first positive test results. The survival model is fit to an expanded data set using easily computed weights. We illustrate with a Weibull survival model and a two-group comparison. The investigator can specify a …

Data-Adaptive Inference Of The Optimal Treatment Rule And Its Mean Reward. The Masked Bandit, Antoine Chambaz, Wenjing Zheng, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

This article studies the data-adaptive inference of an optimal treatment rule. A treatment rule is an individualized treatment strategy in which treatment assignment for a patient is based on her measured baseline covariates. Eventually, a reward is measured on the patient. We also infer the mean reward under the optimal treatment rule. We do so in the so called non-exceptional case, i.e., assuming that there is no stratum of the baseline covariates where treatment is neither beneficial nor harmful, and under a companion margin assumption.

Our pivotal estimator, whose definition hinges on the targeted minimum loss estimation (TMLE) principle, actually …

A Weighted Instrumental Variable Estimator To Control For Instrument-Outcome Confounders, Douglas Lehmann, Yun Li, Rajiv Saran, Yi Li

The University of Michigan Department of Biostatistics Working Paper Series

No abstract provided.

Recommendation To Use Exact P-Values In Biomarker Discovery Research, Margaret Sullivan Pepe, Matthew F. Buas, Christopher I. Li, Garnet L. Anderson

UW Biostatistics Working Paper Series

Background: In biomarker discovery studies, markers are ranked for validation using P-values. Standard P-value calculations use normal approximations that may not be valid for small P-values and small sample sizes common in discovery research.

Methods: We compared exact P-values, valid by definition, with normal and logit-normal approximations in a simulated study of 40 cases and 160 controls. The key measure of biomarker performance was sensitivity at 90% specificity. Data for 3000 uninformative markers and 30 true markers were generated randomly, with 10 replications of the simulation. We also analyzed real data on 2371 antibody array markers …