Biostatistics Commons^™

Testing Gene-Environment Interactions In The Presence Of Measurement Error, Chongzhi Di, Li Hsu, Charles Kooperberg, Alex Reiner, Ross Prentice

UW Biostatistics Working Paper Series

Complex diseases result from an interplay between genetic and environmental risk factors, and it is of great interest to study the gene-environment interaction (GxE) to understand the etiology of complex diseases. Recent developments in genetics field allows one to study GxE systematically. However, one difficulty with GxE arises from the fact that environmental exposures are often measured with error. In this paper, we focus on testing GxE when the environmental exposure E is subject to measurement error. Surprisingly, contrast to the well-established results that the naive test ignoring measurement error is valid in testing the main effects, we find that …

Personalized Evaluation Of Biomarker Value: A Cost-Benefit Perspective, Ying Huang, Eric Laber

UW Biostatistics Working Paper Series

For a patient who is facing a treatment decision, the added value of information provided by a biomarker depends on the individual patient’s expected response to treatment with and without the biomarker, as well as his/her tolerance of disease and treatment harm. However, individualized estimators of the value of a biomarker are lacking. We propose a new graphical tool named the subject-specific expected benefit curve for quantifying the personalized value of a biomarker in aiding a treatment decision. We develop semiparametric estimators for two general settings: i) when biomarker data are available from a randomized trial; and ii) when biomarker …

Identifying Genetic Variants For Heart Rate Variability In The Acetylcholine Pathway, Harriëtte Riese, Loretto M. Muñoz, Catharina A. Hartman, Xiuhua Ding, Shaoyong Su, Albertine J. Oldehinkel, Arie M. Van Roon, Peter J. Van Der Most, Joop Lefrandt, Ron T. Gansevoort, Pim Van Der Harst, Niek Verweij, Carmilla M. M. Licht, Dorret I. Boomsma, Jouke-Jan Hottenga, Gonneke Willemsen, Brenda W. J. H. Penninx, Ilja M. Nolte, Eco J. C. De Geus, Xiaoling Wang, Harold Snieder

Biostatistics Faculty Publications

Heart rate variability is an important risk factor for cardiovascular disease and all-cause mortality. The acetylcholine pathway plays a key role in explaining heart rate variability in humans. We assessed whether 443 genotyped and imputed common genetic variants in eight key genes (CHAT, SLC18A3, SLC5A7, CHRNB4, CHRNA3, CHRNA, CHRM2 and ACHE) of the acetylcholine pathway were associated with variation in an established measure of heart rate variability reflecting parasympathetic control of the heart rhythm, the root mean square of successive differences (RMSSD) of normal RR intervals. The association was studied in a …

Cross-Design Synthesis For Extending The Applicability Of Trial Evidence When Treatment Effect Is Heterogeneous-I. Methodology, Ravi Varadhan, Carlos Weiss

Johns Hopkins University, Dept. of Biostatistics Working Papers

Randomized controlled trials (RCTs) provide reliable evidence for approval of new treatments, informing clinical practice, and coverage decisions. The participants in RCTs are often not a representative sample of the larger at-risk population. Hence it is argued that the average treatment effect from the trial is not generalizable to the larger at-risk population. An essential premise of this argument is that there is significant heterogeneity in the treatment effect (HTE). We present a new method to extrapolate the treatment effect from a trial to a target group that is inadequately represented in the trial, when HTE is present. Our method …

Cross-Design Synthesis For Extending The Applicability Of Trial Evidence When Treatment Effect Is Heterogeneous. Part Ii. Application And External Validation, Carlos Weiss, Ravi Varadhan

Johns Hopkins University, Dept. of Biostatistics Working Papers

Randomized controlled trials (RCTs) generally provide the most reliable evidence. When participants in RCTs are selected with respect to characteristics that are potential treatment effect modifiers, the average treatment effect from the trials may not be applicable to a specific target population. We present a new method to project the treatment effect from a RCT to a target group that is inadequately represented in the trial when there is heterogeneity in the treatment effect (HTE). The method integrates RCT and observational data through cross-design synthesis. An essential component is to identify HTE and a calibration factor for unmeasured confounding for …

Enhanced Precision In The Analysis Of Randomized Trials With Ordinal Outcomes, Iván Díaz, Elizabeth Colantuoni, Michael Rosenblum

Johns Hopkins University, Dept. of Biostatistics Working Papers

We present a general method for estimating the effect of a treatment on an ordinal outcome in randomized trials. The method is robust in that it does not rely on the proportional odds assumption. Our estimator leverages information in prognostic baseline variables, and has all of the following properties: (i) it is consistent; (ii) it is locally efficient; (iii) it is guaranteed to match or improve the precision of the standard, unadjusted estimator. To the best of our knowledge, this is the first estimator of the causal relation between a treatment and an ordinal outcome to satisfy these properties. We …

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 …

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 …

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.

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, …

Optimalisasi Sistem Pelayanan Kesehatan Berjenjang Pada Program Kartu Jakarta Sehat, Fachmi Idris

Kesmas

Peningkatan jumlah kunjungan pasien ke rumah sakit pada awal masa pemberlakuan program Kartu Jakarta Sehat (KJS) disebabkan belum optimalnya sistem pelayanan kesehatan berjenjang. PT Asuransi Kesehatan (PT Askes) bersama Dinas Kesehatan DKI Jakarta melakukan berbagai upaya dalam bentuk paket intervensi untuk mengoptimalkan sistem tersebut. Penelitian ini bertujuan untuk mengevaluasi efektivitas paket intervensi PT Askes dan Dinas Kesehatan DKI Jakarta dalam meningkatkan optimilisasi sistem rujukan pelayanan kesehatan. Penelitian ini menggunakan survei potong lintang dengan metode pengambilan sampel acak pada puskesmas di DKI Jakarta terhadap hasil intervensi PT Askes. Hasil intervensi diukur melalui wawancara pada kepala puskesmas atau petugas yang mewakili. Data …

Penelitian Genom Dan Implikasinya Dalam Kesehatan Masyarakat Di Indonesia, Doni Hikmat Ramdhan

Kesmas

Penelitian genom yang mengkaji kaitan antara setiap gen dengan suatu penyakit sekaligus mekanismenya untuk mendapatkan pengetahuan yang menyeluruh dalam pengobatan, telah membawa perubahan besar dunia kedokteran dalam mengobati berbagai penyakit. Namun demikian, penelitian genom seharusnya tidak hanya dimanfaatkan untuk pengobatan tetapi juga untuk pencegahan penyakit. Artikel ini membahas masalah kesehatan masyarakat dan peluang pemanfaatan penelitian genom dalam pencegahan penyakit. Penelitian genom yang dapat dimanfaatkan pada bidang kesehatan masyarakat adalah toksikogenomik dan nutrigenomik. Penelitian toksikogenomik mengkaji respons gen akibat pajanan toksikan yang berdampak pada kesehatan manusia. Penelitian nutrigenomik mengkaji respons gen terhadap makanan yang berdampak pada kesehatan manusia. Penelitian toksikogenomik dan …

Pengaruh Pendekatan Child Healthcare Modeldan Transtheoretical Model Terhadap Asupan Makan Anak Overweight Dan Obesitas, Kadek Ayu Erika, Elly Nurachmah

Kesmas

Overweight dan obesitas pada anak merupakan suatu masalah yang kompleks disebabkan multifaktor, yaitu interaksi genetik dan lingkungan. Gaya hidup perkotaan dipicu oleh asupan makanan yang berlebih pada anak overweight dan obesitas. Strategi untuk menurunkan asupan makan berlebih pada anak adalah dengan pendekatan child healthcare model dan transtheoretical model sehingga dapat mengendalikan gaya hidup anak. Penelitian ini bertujuan membuktikan pengaruh pendekatan child healthcare dan transtheoretical model terhadap asupan karbohidrat anak overweight dan obesitas. Penelitian ini dilaksanakan di wilayah kecamatan Biringkanaya dan Tamalanrea, Makassar, pada bulan Agustus 2013 sampai Maret 2014. Desain yang digunakan adalah quasy experiment yaitu pretest and posttest with …

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. …

Diagnosis Dini Tuberkulosis Pada Kontak Serumah Dengan Penderita Tuberkulosis Paru Melalui Deteksi Kadar Ifn-Γ, Sri Andarini Indreswari, Suharyo Suharyo

Kesmas

Tuberkulosis paru masih merupakan masalah dunia. Indonesia menempati peringkat ke tiga di dunia pada tahun 2012. Target nasional Case Detection Rate tahun 2012 adalah 70%, sedangkan pencapaian Jawa Tengah sebesar 58,48%. Penelitian ini bertujuan untuk memperoleh batas kadar interferon (IFN) γ pada orang kontak serumah dengan penderita tuberkulosis paru sebagai dasar diagnosis dini penyakit tuberkulosis. Penelitian dilakukan secara kohort selama dua tahun (2011 - 2013) di Balai Kesehatan Masyarakat Paru Semarang. Pada akhir penelitian, terdapat 12 responden kontak dan 13 tidak kontak serumah. Uji Wilcoxon menunjukkan perbedaan bermakna rerata kadar IFN-γ antara kelompok kontak dengan kelompok tidak kontak serumah (nilai …

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. …

Pertumbuhan Dan Perkembangan Anak Usia 3-24 Bulan Di Daerah Konflik, Hastuti Usman, Hadyana Sukandar, Ma’Mun Sutisna

Kesmas

Lima tahun pertama adalah masa penting dalam proses tumbuh kembang anak. Anak lahir dan tinggal di daerah rawan bencana (bencana alam, perang, atau konflik bersenjata) berisiko mengalami kegagalan pertumbuhan dan keterlambatan perkembangan. Penelitian ini bertujuan mengukur perbedaan pertumbuhan dan perkembangan anak usia 3 - 24 bulan antara yang tinggal di daerah konflik dan bukan konflik dan menganalisis korelasi tempat tinggal daerah konflik dengan pertumbuhan serta perkembangan anak usia 3 - 24 bulan. Metode penelitian secara potong lintang dilakukan di Kabupaten Poso periode Februari - Maret 2014 terhadap 40 anak usia 3 - 24 bulan di daerah konflik dan bukan konflik. …

Malnutrisi Akut Berat Dan Determinannya Pada Balita Di Wilayah Rural Dan Urban, Titih Huriah, Laksono Trisnantoro, Fitri Haryanti, Madarina Julia

Kesmas

Malnutrisi akut berat merupakan malnutrisi yang paling serius yang memengaruhi balita dan merupakan masalah kesehatan utama di negara-negara berkembang. Malnutrisi telah meluas baik di perkotaan maupun perdesaan. Akar permasalahan malnutrisi di negara berkembang salah satunya adalah faktor sosial demografi. Tujuan penelitian untuk melihat perbedaan kejadian malnutrisi dan determinannya di area perkotaan dan pedesaan di Yogyakarta. Penelitian menggunakan desain potong lintang dengan responden adalah semua balita malnutrisi akut berat di Kabupaten Sleman (23 balita) dan Kota Yogyakarta (33 balita). Analisis data menggunakan statistik deskriptif dan inferensial. Penelitian dilaksanakan pada Bulan Desember 2012 - Februari 2013. Prevalensi balita malnutrisi akut lebih banyak …

Pendapatan Daerah, Pembiayaan Kesehatan, Dan Gizi Buruk Pada Balita: Studi Korelasi Tingkat Kabupaten/Kota, Septyana Choirunisa, Asri C. Adisasmita

Kesmas

Pendanaan kesehatan merupakan salah satu faktor penting dalam memengaruhi derajat kesehatan, termasuk salah satu masalah gizi pada balita yang disebut gizi buruk. Oleh karena itu, penelitian ini bertujuan mendeskripsikan pendapatan daerah dan pembiayaan kesehatan serta korelasinya dengan gizi buruk pada balita di tingkat kabupaten/kota di Indonesia tahun 2007. Penelitian ini merupakan studi ekologi/korelasi. Data pendapatan daerah dan pembiayaan kesehatan didapat dari Kementerian Keuangan, sedangkan data gizi buruk menggunakan data Riset Kesehatan Nasional tahun 2007. Sebanyak 250 kabupaten/kota yang diteliti dengan tidak mengikutsertakan kabupaten/kota yang datanya tidak lengkap atau tidak valid. Secara nasional, hanya persentase pendapatan asli daerah (PAD) per total …

Evaluasi Pelaksanaan Konseling Menyusui, Ika Murtiyarini, Dewi Marhaeni Diah Herawati, Irvan Afriandi

Kesmas

Salah satu upaya pemerintah dalam meningkatkan pemberian ASI di Indonesia adalah dengan memberikan konseling menyusui di pelayanan kesehatan. Penelitian perlu dilakukan untuk mengevaluasi pelaksanaan konseling menyusui di Kota Jambi dengan mengeksplorasi komponen input, activity, output, dan outcome. Penelitian ini merupakan penelitian kualitatif menggunakan strategi studi kasus. Penelitian dilakukan di empat puskesmas Kota Jambi pada bulan Desember 2013 sampai dengan Februari 2014. Pengumpulan data dilakukan dengan studi dokumen, observasi pelaksanaan konseling menyusui dan sarana prasarana, wawancara mendalam, serta focus group discussion. Analisis data yang digunakan adalah analisis tematik. Hasil penelitian menunjukkan bahwa komponen input dan activity kurang optimal seperti kurangnya sumber …

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 …

Family Role Towards Smoking Behaviour Among Children In Jakarta, Wahyu Septiono, Dan Wolf Meyrowitsch

Kesmas

In Indonesia, the prevalence of smoking among 5 – 9 years old children has increased from 0.4% in 2001 to 2% in 2007. Among present adults smokers (>20 years), 17% started to smoke before the age of 13 years. This study identified factors related to smoking behaviour among 8 – 12 years old children in Jakarta, Indonesia using a questionnaire based cross sectional survey to obtain smoking status and possible predictors towards smoking habit. The total sample size was 1,097 students among 3rd - 7th grade students from schools in Jakarta. Self-reported smoking status was defined as whether the …