Biostatistics Commons^™

Applications Of The Wei-Lachin Multivariate One-Sided Test For Multiple Outcomes On Possibly Different Scales, John M. Lachin

GW Biostatistics Center

Many studies aim to assess whether a therapy has a beneficial effect on multiple outcomes simultaneously relative to a control. Often the joint null hypothesis of no difference for the set of outcomes is tested using separate tests with a correction for multiple tests, or using a multivariate T2-like MANOVA or global test. However, a more powerful test in this case is a multivariate one-sided or one-directional test directed at detecting a simultaneous beneficial treatment effect on each outcome, though not necessarily of the same magnitude. The Wei-Lachin test is a simple 1 df test obtained from a simple …

Optimal Bayesian Adaptive Trials When Treatment Efficacy Depends On Biomarkers, Yifan Zhang, Lorenzo Trippa, Giovanni Parmigiani

Harvard University Biostatistics Working Paper Series

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% …

Generalized Quantile Treatment Effect, Sergio Venturini, Francesca Dominici, Giovanni Parmigiani

Harvard University Biostatistics Working Paper Series

No abstract provided.

A Bayesian Approach To Joint Modeling Of Menstrual Cycle Length And Fecundity, Kirsten J. Lum, Rajeshwari Sundaram, Germaine M. Buck-Louis, Thomas A. Louis

Johns Hopkins University, Dept. of Biostatistics Working Papers

Female menstrual cycle length is thought to play an important role in couple fecundity, or the biologic capacity for reproduction irrespective of pregnancy intentions. A complete assessment of the association between menstrual cycle length and fecundity requires a model that accounts for multiple risk factors (both male and female) and the couple's intercourse pattern relative to ovulation. We employ a Bayesian joint model consisting of a mixed effects accelerated failure time model for longitudinal menstrual cycle lengths and a hierarchical model for the conditional probability of pregnancy in a menstrual cycle given no pregnancy in previous cycles of trying, in …

An Overview Of Statistical Approaches For Comparative Effectiveness Research For Assessing In-Hospital Complications Of Percutaneous Coronary Interventions By Access Site, Lauren Kunz, Sherri Rose, Donna Spiegelman, Sharon-Lise Normand

Sherri Rose

No abstract provided.

Using Graphs To Characterize Nationwide Physician Referral Networks, Ding Tong, Shu-Xia Li, Isuru Ranasinghe, Sudhakar Nuti, Hongyu Zhao, Harlan Krumholz

Yale Day of Data

AIM:

Evaluating physician referral network characteristics can help to understand how physicians and hospitals interact to provide patient services within the US healthcare system and ultimately how this may influence patient outcomes.

METHOD:

We used the 2012-2013 national Physician Referral data from the Centers for Medicare & Medicaid Services (CMS), which consists of 73,071,804 pairs of referrals from one health provider to another in calendar year 2012 and the first two quarters of year 2013 within 30 days of care. These referrals are from 642,144 national-wide physicians and 4,811 hospitals. We obtained information for each provider, physician or hospital, from …

Stratified Meta-Analysis To Examine Data Biases In Lung Cancer Studies Of Refinery Workers, Sherman Selix

Yale Day of Data

Petroleum refineries employ a variety of workers who historically experienced different potentials for asbestos exposure depending on job tasks. Associations between petroleum refinery work and lung cancer related to occupational asbestos exposure have been quantified among various locations, corporations, and time periods. To combine the data from several individual refinery studies and examine an overall effect, a systematic review and stratified meta-analysis was employed. Using set search terms among four databases, 112 potential publications were identified, of which 29 qualified for meta-analysis. Risk estimates and confidence intervals were extracted from these publications to construct four separate datasets. Inverse variance weighting …

Online Targeted Learning, Mark J. Van Der Laan, Samuel D. Lendle

U.C. Berkeley Division of Biostatistics Working Paper Series

We consider the case that the data comes in sequentially and can be viewed as sample of independent and identically distributed observations from a fixed data generating distribution. The goal is to estimate a particular path wise target parameter of this data generating distribution that is known to be an element of a particular semi-parametric statistical model. We want our estimator to be asymptotically efficient, but we also want that our estimator can be calculated by updating the current estimator based on the new block of data without having to revisit the past data, so that it is computationally much …

Lung Flute Improves Symptoms And Health Status In Copd With Chronic Bronchitis: A 26 Week Randomized Controlled Trial, Sanjay Sethi, Jingjing Yin, Pamela K. Anderson

Biostatistics Faculty Publications

Background: Chronic obstructive pulmonary disease (COPD) is characterized by mucus hypersecretion that contributes to disease related morbidity and is associated with increased mortality. The Lung Flute® is a new respiratory device that produces a low frequency acoustic wave with moderately vigorous exhalation to increase mucus clearance. We hypothesized that the Lung Flute, used on a twice daily basis will provide clinical benefit to patients with COPD with chronic bronchitis.

Methods: We performed a 26 week randomized, non-intervention controlled, single center, open label trial in 69 patients with COPD and Chronic Bronchitis. The primary endpoint was change in respiratory symptoms measured …

Cluster Randomized Trials And Statistical Power, Stephen A. Lauer, Nicholas G. Reich

Nicholas G Reich

The cluster-randomized trial (CRT) is a common study design in public health research. In situations where dividing a group of individuals into treatment and controls is unethical or impossible, a CRT design maintains the strengths of a randomized study design. By comparing the outcomes of small populations (clusters), we can observe the impacts of interventions on the community as a whole. Public health researchers around the world have utilized CRTs to measure the effect of, for example, de-worming medication on school attendance, financial incentives on doctor absenteeism, and providing chlorine to waterholes. The CRT can be a potent tool, however …

Functional Analysis Of Variance For Association Studies, Olga A. Vsevolozhskaya, Dmitri V. Zaykin, Mark C. Greenwood, Changshuai Wei, Qing Lu

Olga A. Vsevolozhskaya

While progress has been made in identifying common genetic variants associated with human diseases, for most of common complex diseases, the identified genetic variants only account for a small proportion of heritability. Challenges remain in finding additional unknown genetic variants predisposing to complex diseases. With the advance in next-generation sequencing technologies, sequencing studies have become commonplace in genetic research. The ongoing exome-sequencing and whole-genome-sequencing studies generate a massive amount of sequencing variants and allow researchers to comprehensively investigate their role in human diseases. The discovery of new disease-associated variants can be enhanced by utilizing powerful and computationally efficient statistical methods. …

Estimation Of The Overall Treatment Effect In The Presence Of Interference In Cluster-Randomized Trials Of Infectious Disease Prevention, Nicole Bohme Carnegie, Rui Wang, Victor De Gruttola

Harvard University Biostatistics Working Paper Series

No abstract provided.

Pubertal And Adult Leydig Cell Function In Mullerian Inhibiting Substance-Deficient Mice, Xiufeng Wu, Ramamani Arumugam, Stephen Baker, Mary Lee

Mary M. Lee

Mullerian inhibiting substance (MIS) causes Mullerian duct regression during sexual differentiation and regulates postnatal Leydig cell development. MIS knockout (MIS-KO) mice with targeted deletions of MIS develop Leydig cell hyperplasia, but their circulating androgen concentrations are reportedly unaltered. We compared reproductive hormone profiles, androgen biosynthesis, and the expression of key steroidogenic and metabolic enzymes in MIS-KO and wild-type (WT) mice at puberty (36 d) and sexual maturity (60 d). In pubertal animals, basal testosterone and LH concentrations in plasma were lower in MIS-KO than WT mice, whereas human chorionic gonadotropin-stimulated testosterone concentrations were similar. In adults, basal LH, and both …

Cox Regression Models With Functional Covariates For Survival Data, Jonathan E. Gellar, Elizabeth Colantuoni, Dale M. Needham, Ciprian M. Crainiceanu

Johns Hopkins University, Dept. of Biostatistics Working Papers

We extend the Cox proportional hazards model to cases when the exposure is a densely sampled functional process, measured at baseline. The fundamental idea is to combine penalized signal regression with methods developed for mixed effects proportional hazards models. The model is fit by maximizing the penalized partial likelihood, with smoothing parameters estimated by a likelihood-based criterion such as AIC or EPIC. The model may be extended to allow for multiple functional predictors, time varying coefficients, and missing or unequally-spaced data. Methods were inspired by and applied to a study of the association between time to death after hospital discharge …

Targeted Learning Of An Optimal Dynamic Treatment, And Statistical Inference For Its Mean Outcome, Mark J. Van Der Laan, Alexander R. Luedtke

U.C. Berkeley Division of Biostatistics Working Paper Series

Suppose we observe n independent and identically distributed observations of a time-dependent random variable consisting of baseline covariates, initial treatment and censoring indicator, intermediate covariates, subsequent treatment and censoring indicator, and a final outcome. For example, this could be data generated by a sequentially randomized controlled trial, where subjects are sequentially randomized to a first line and second line treatment, possibly assigned in response to an intermediate biomarker, and are subject to right-censoring. In this article we consider estimation of an optimal dynamic multiple time-point treatment rule defined as the rule that maximizes the mean outcome under the dynamic treatment, …

Fertilitas Remaja Di Indonesia, Mugia Bayu Raharja

Kesmas

Fertilitas remaja merupakan isu penting dari segi kesehatan dan sosial karena berhubungan dengan tingkat morbiditas serta mortalitas ibu dan anak. Tujuan penelitian adalah mempelajari faktor-faktor yang memengaruhi fertilitas remaja di Indonesia. Data yang digunakan adalah hasil Survei Demografi dan Kesehatan Indonesia tahun 2012 dengan unit analisis wanita usia subur yang termasuk dalam kategori usia remaja (15 - 19 tahun). Jumlah sampel sebanyak 6.927 responden. Analisis dilakukan dengan metode deskriptif dan inferensial menggunakan model regresi logistik biner. Hasil analisis menunjukkan bahwa satu dari sepuluh remaja wanita tersebut pernah melahirkan dan atau sedang hamil saat survei dilakukan; sebesar 95,2% dari remaja yang …

Tingkat Pengetahuan Dan Persepsi Terhadap Shisha Pada Mahasiswa, Dhimas Nirwana Yudha, Yayi Suryo Prabandari, Purwanta Purwanta

Kesmas

Isu yang berkembang terkait pengetahuan dan persepsi seorang calon tenaga kesehatan memengaruhi keberhasilan pelayanan kesehatan dalam menjawab tantangan di masyarakat nantinya. Shisha (rokok dari Timur Tengah) mulai marak di Yogyakarta. Tujuan penelitian ini untuk memperoleh gambaran tentang tingkat pengetahuan dan persepsi terhadap shisha pada mahasiswa reguler tahap akademik Fakultas Kedokteran Universitas Gadjah Mada. Penelitian ini merupakan penelitian deskriptif menggunakan rancangan potong lintang. Sampel penelitian adalah mahasiswa dari tiga program studi yang dilakukan pada bulan September - Oktober 2013. Jumlah responden sebanyak 72 mahasiswa ilmu keperawatan, 74 mahasiswa gizi dan kesehatan dan 258 mahasiswa pendidikan dokter. Pengumpulan data dilakukan dengan kuesioner. …

Pattern Of Household Drug Storage, Retno Gitawati

Kesmas

Household storage of pharmaceutical is world-widely practice, including in Indonesia. The purpose of this study was to obtain the pattern of medicine storage, the sources and reasons of medicine kept in households. Acrosssectional survey was conducted on October 2011, involving 250 adult household respondents, randomly selected from three subdistricts in North Jakarta, and have approved the written consents, and interviewed with structured questionnaire. Data were performed in univariate and bivariate analysis with chi square test. The majority of household (82%) stored drugs at home; analgesic-antipyretic nonsteroidal anti-inflammatory was the type of drugs kept by mostly (76.1%) of household. Out of …

Peningkatan Determinan Sosial Dalam Menurunkan Kejadian Tuberkulosis Paru, Dyah Wulan Sumekar Rengganis Wardani

Kesmas

Upaya pengendalian tuberkulosis paru oleh World Health Organization telah meningkatkan angka kesembuhan dan menyelamatkan banyak jiwa, tetapi kurang berhasil dalam menurunkan insiden tuberkulosis. Oleh karena itu, pengendalian tuberkulosis akan lebih menekankan pada kebijakan determinan sosial karena determinan sosial secara langsung maupun melalui faktor risiko tuberkulosis berpengaruh terhadap tuberkulosis. Di Bandar Lampung, angka notifikasi tuberkulosis dari tahun 2009 – 2010 mengalami peningkatan walaupun angka kesembuhan sudah lebih dari 85%. Bandar Lampung juga merupakan bagian dari salah satu provinsi termiskin di Indonesia. Penelitian ini bertujuan untuk mempelajari pengaruh determinan sosial (yang diukur melalui indikator pendidikan, pendapatan dan kelas sosial) terhadap kejadian tuberkulosis. …