Biostatistics Commons^™

Identification Of Prognostic Genes And Gene Sets For Early-Stage Non-Small Cell Lung Cancer Using Bi-Level Selection Methods, Suyan Tian, Chi Wang, Howard H. Chang, Jianguo Sun

Biostatistics Faculty Publications

In contrast to feature selection and gene set analysis, bi-level selection is a process of selecting not only important gene sets but also important genes within those gene sets. Depending on the order of selections, a bi-level selection method can be classified into three categories – forward selection, which first selects relevant gene sets followed by the selection of relevant individual genes; backward selection which takes the reversed order; and simultaneous selection, which performs the two tasks simultaneously usually with the aids of a penalized regression model. To test the existence of subtype-specific prognostic genes for non-small cell lung cancer …

Outcomes After Diagnosis Of Mild Cognitive Impairment In A Large Autopsy Series, Erin L. Abner, Richard J. Kryscio, Frederick A. Schmitt, David W. Fardo, Daniela C. Moga, Eseosa T. Ighodaro, Gregory A. Jicha, Lei Yu, Hiroko H. Dodge, Chengjie Xiong, Randall L. Woltjer, Julie A. Schneider, Nigel J. Cairns, David A. Bennett, Peter T. Nelson

Epidemiology and Environmental Health Faculty Publications

OBJECTIVE: To determine clinical and neuropathological outcomes following a clinical diagnosis of mild cognitive impairment (MCI).

METHODS: Data were drawn from a large autopsy series (N = 1,337) of individuals followed longitudinally from normal or MCI status to death, derived from 4 Alzheimer Disease (AD) Centers in the United States.

RESULTS: Mean follow‐up was 7.9 years. Of the 874 individuals ever diagnosed with MCI, final clinical diagnoses were varied: 39.2% died with an MCI diagnosis, 46.8% with a dementia diagnosis, and 13.9% with a diagnosis of intact cognition. The latter group had pathological features resembling those with a final clinical …

Pre-Pregnancy Body Mass Index Is Associated With Dietary Inflammatory Index And C-Reactive Protein Concentrations During Pregnancy, Dayeon Shin, Junguk Hur, Eun-Hee Cho, Hae-Kyung Chung, Nitin Shivappa, Michael D. Wirth, James R. Hébert, Kyung Won Lee

Faculty Publications

There have been a limited number of studies examining the association between pre-pregnancy body mass index (BMI) and dietary inflammation during pregnancy. Our aim is to examine the association between pre-pregnancy BMI and the Dietary Inflammatory Index (DII)™ and C-reactive protein (CRP) concentrations during pregnancy. The study included 631 pregnant American women from the National Health and Nutrition Examination Survey (NHANES) cross-sectional examinations from 2003 to 2012. Pre-pregnancy BMI was calculated based on self-reported pre-pregnancy weight and measured height. The cut-offs of <18.5 (underweight), 18.5–24.9 (normal), 25.0–29.9 (overweight), and ≥30 kg/m2 (obese) were used to categorize the weight status of pregnant women prior to pregnancy. The DII, a literature-based dietary index to assess the inflammatory properties of diet, was estimated based on a one-day 24-h recall. Multivariable linear and logistic regressions were performed to estimate beta coefficients and the adjusted odds ratios (AORs) and 95% confidence intervals (95% CIs) on the association of pre-pregnancy BMI categories with the DII and CRP concentrations during pregnancy. After controlling for variables including: race/ethnicity, family poverty income ratio, education, marital status, month in pregnancy, and smoking status during pregnancy; women who were obese before pregnancy (n = 136) had increased odds for being in the highest tertile of the DII and CRP concentrations compared to women with normal weight (AORs 2.40, 95% CIs 1.01–5.71; AORs 24.84, 95% CIs 6.19–99.67, respectively). These findings suggest that women with pre-pregnancy obesity had greater odds of reporting higher DII and having elevated CRP. In conclusion, high pre-pregnancy BMI was associated with increased odds of pro-inflammatory diet and elevated CRP levels during pregnancy in the USA.

Level Of Patient-Physician Agreement In Assessment Of Change Following Conservative Rehabilitation For Shoulder Pain, Stephanie D. Moore-Reed, W. Ben Kibler, Heather M. Bush, Timothy L. Uhl

Biostatistics Faculty Publications

Background Assessment of health-related status has been shown to vary between patients and physicians, although the degree of patient–physician discordance in the assessment of the change in status is unknown.

Methods Ninety-nine patients with shoulder dysfunction underwent a standardized physician examination and completed several self-reported questionnaires. All patients were prescribed the same physical therapy intervention. Six weeks later, the patients returned to the physician, when self-report questionnaires were re-assessed and the Global Rating of Change (GROC) was completed by the patient. The physician completed the GROC retrospectively. To determine agreement between patient and physician, intra-class correlation (ICC) coefficient and Pearson’s …

Examining The Prevalence Rates Of Preexisting Maternal Medical Conditions And Pregnancy Complications By Source: Evidence To Inform Maternal And Child Research, Candace A. Robledo, Edwina H. Yeung, Pauline Mendola, Rajeshwari Sundaram, Nansi S. Boghossian, Erin M. Bell, Charlotte Druschel

School of Medicine Publications

Objectives—We sought to examine whether there are systematic differences in ascertainment of preexisting maternal medical conditions and pregnancy complications from three common data sources used in epidemiologic research

Methods—Diabetes mellitus, chronic hypertension, gestational diabetes mellitus (GDM), gestational hypertensive disorders (GHD), placental abruption and premature rupture of membranes (PROM) among 4821 pregnancies were identified via birth certificates, maternal self-report at approximately 4 months postpartum and by discharge codes from the Statewide Planning and Research Cooperative System (SPARCS), a mandatory New York State hospital reporting system. The kappa statistic (k) was estimated to ascertain beyond chance agreement of outcomes between birth certificates …

Contributions To Statistical Testing, Prediction, And Modeling, John C. Pesko

Mathematics & Statistics ETDs

1. "Parametric Bootstrap (PB) and Objective Bayesian (OB) Testing with Applications to Heteroscedastic ANOVA": For one-way heteroscedastic ANOVA, we show a close relationship between the PB and OB approaches to significance testing, demonstrating the conditions for which the two approaches are equivalent. Using a simulation study, PB and OB performance is compared to a test based on the predictive distribution as well as the unweighted test of Akritas & Papadatos (2004). We extend this work to the RCBD with subsampling model, and prove a repeated sampling property and large sample property for general OB significance testing.

2. "Early Identification of …

Using The Roc Curve To Measure Association And Evaluate Prediction Accuracy For A Binary Outcome, Jingjing Yin, Robert L. Vogel

Biostatistics: Faculty Publications

This review article addresses the ROC curve and its advantage over the odds ratio to measure the association between a continuous variable and a binary outcome. A simple parametric model under the normality assumption and the method of Box-Cox transformation for non-normal data are discussed. Applications of the binormal model and the Box-Cox transformation under both univariate and multivariate inference are illustrated by a comprehensive data analysis tutorial. Finally, a summary and recommendations are given as to the usage of the binormal ROC curve.

A Statistical Method For The Conservative Adjustment Of False Discovery Rate (Q-Value)., Yinglei Lai

Epidemiology Faculty Publications

BACKGROUND: q-value is a widely used statistical method for estimating false discovery rate (FDR), which is a conventional significance measure in the analysis of genome-wide expression data. q-value is a random variable and it may underestimate FDR in practice. An underestimated FDR can lead to unexpected false discoveries in the follow-up validation experiments. This issue has not been well addressed in literature, especially in the situation when the permutation procedure is necessary for p-value calculation.

RESULTS: We proposed a statistical method for the conservative adjustment of q-value. In practice, it is usually necessary to calculate p-value by a permutation procedure. …

A Statistical Method For The Conservative Adjustment Of False Discovery Rate (Q-Value), Yinglei Lai

Epidemiology Faculty Publications

Background

q-value is a widely used statistical method for estimating false discovery rate (FDR), which is a conventional significance measure in the analysis of genome-wide expression data. q-value is a random variable and it may underestimate FDR in practice. An underestimated FDR can lead to unexpected false discoveries in the follow-up validation experiments. This issue has not been well addressed in literature, especially in the situation when the permutation procedure is necessary for p-value calculation.

Results

We proposed a statistical method for the conservative adjustment of q-value. In practice, it is usually necessary to calculate p …

Using A Respiratory Navigator Significantly Reduces Variability When Quantifying Left Ventricular Torsion With Cardiovascular Magnetic Resonance, Sean M. Hamlet, Christopher M. Haggerty, Jonathan D. Suever, Gregory J. Wehner, Kristin N. Andres, David K. Powell, Richard J. Charnigo, Brandon K. Fornwalt

Electrical and Computer Engineering Faculty Publications

Background: Left ventricular (LV) torsion is an important indicator of cardiac function that is limited by high inter-test variability (50% of the mean value). We hypothesized that this high inter-test variability is partly due to inconsistent breath-hold positions during serial image acquisitions, which could be significantly improved by using a respiratory navigator for cardiovascular magnetic resonance (CMR) based quantification of LV torsion.

Methods: We assessed respiratory-related variability in measured LV torsion with two distinct experimental protocols. First, 17 volunteers were recruited for CMR with cine displacement encoding with stimulated echoes (DENSE) in which a respiratory navigator was used to measure …

Using Ranked Auxiliary Covariate As A More Efficient Sampling Design For Ancova Model: Analysis Of A Psychological Intervention To Buttress Resilience, Rajai Jabrah, Hani Samawi, Robert Vogel, Haresh Rochani, Daniel Linder

Biostatistics: Faculty Publications

Drawing a sample can be costly or time consuming in some studies. However, it may be possible to rank the sampling units according to some baseline auxiliary covariates, which are easily obtainable, and/or cost efficient. Ranked set sampling (RSS) is a method to achieve this goal. In this paper, we propose a modified approach of the RSS method to allocate units into an experimental study that compares L groups. Computer simulation estimates the empirical nominal values and the empirical power values for the test procedure of comparing L different groups using modified RSS based on the regression approach in analysis …

The Impact Of National Health Insurance Policy To The Implementation Of Health Promotion Program On Public Health Center In Indonesia, Mochamad Iqbal Nurmansyah, Bulent Kilic

Kesmas

Jaminan Kesehatan Nasional (JKN) telah diimplementasikan di Indonesia pada 1 Januari 2014. Hal tersebut membawa beberapa perubahan pada aspek manajerial pada pusat kesehatan masyarakat (puskesmas). Penelitian ini bertujuan untuk mengidentifikasi dampak dari kebijakan JKN terhadap implementasi program promosi kesehatan di puskesmas di Kota Tangerang Selatan, Indonesia. Penelitian menggunakan metode kualitatif. Data dikumpulkan pada Februari – Maret 2016. Dampak program dilihat dalam hal kebijakan, pendanaan, fasilitas, sumber daya manusia dan pelaksanaan program promosi kesehatan. Dengan menggunakan metode purposive sampling, enam pengambil kebijakan, delapan pemberi layanan dan delapan penerima layanan diambil sebagai informan dalam penelitian ini. Pada analisis dokumen, 17 dokumen telah …

Effect Of School Community Empowerment Model Towards Handwashing Implementation Among Elementary School Students In Dayeuhkolot Subdistrict, Tetti Solehati, Cecep Eli Kosasih, Sri Susilawati, Mamat Lukman, Sayu Putu Yuni Paryati

Kesmas

Perilaku mencuci tangan dengan sabun di Indonesia masih menjadi masalah. Penyebabnya dikaitkan dengan kurangnya kesadaran dalam mencuci tangan pakai sabun. Penelitian ini bertujuan untuk mengetahui pengaruh pemberdayaan komunitas sekolah terhadap penerapan mencuci tangan di kalangan siswa sekolah dasar di Kecamatan Dayeuhkolot, Kabupaten Bandung. Penelitian ini menggunakan desain quasi eksperimental dengan pretest dan posttest serta melakukan analisis deskriptif dan inferensial. Sampel terdiri dari 24 guru, 377 siswa di kelas 4-6, dan 24 dokter kecil. Metode pendekatan dalam penelitian ini menggunakan usaha kesehatan sekolah terpadu (gabungan model fit for school dan UKS terpilih), yang terdiri dari enam tahap. Instrumen terdiri dari kuesioner …

Acceptance Of Medical Resume Completion At Dr. Radjiman Wediodiningrat Lawang Psychiatric Hospital, Silvia Shinta Devi, Aryo Dewanto, Lukman Hakim

Kesmas

Sistem kesehatan di Indonesia mengalami perubahan besar dengan diberlakukannya program Asuransi Kesehatan Nasional. Resume medis memiliki peran penting dalam klaim asuransi kesehatan, sehingga resume medis yang terlambat dan tidak lengkap akan mengganggu proses klaim asuransi. Penelitian ini bertujuan untuk mengetahui pengaruh persepsi kemudahan penggunaan, persepsi manfaat, dan sikap pada penerimaan dokter dalam menyelesaikan resume medis. di Dr Radjiman Wedyodiningrat Psychiatric Hospital Lawang berdasarkan Technology Acceptance Model. Technology Acceptance Model digunakan sebagai model dalam penelitian ini karena resume medis merupakan salah satu bentuk teknologi informasi yang masih dilakukan secara manual. Pengumpulan data untuk penelitian ini dilakukan pada bulan Maret 2016 dengan …

Risk Factors Of Carpal Tunnel Syndrome In Food-Packing Workers Karanganyar, Haris Setyawan

Kesmas

Carpal tunnel syndrome (CTS) terjadi ketika saraf median, yang membentang dari lengan bawah ke tangan, mengalami tekanan atau terpuntir di pergelangan tangan. Hasilnya mungkin sakit, kelemahan atau mati rasa di tangan dan pergelangan tangan, yang memancar ke lengan tangan. Penelitian ini bertujuan untuk mengkaji faktor risiko usia, jenis kelamin, masa kerja dan gerakan repetitif terhadap keluhan CTS pada pekerja pengepakan makanan di Karanganyar. Penelitian ini dilaksanakan pada bulan Oktober – Desember 2014 menggunakan desain observational analitik dengan penelitian potong lintang. Sampel terdiri dari 50 orang dari total 67 pekerja pengepak makanan di kawasan industri Jaten Karanganyar yang diambil dengan menggunakan …

Psychosocial Determinants Of Risky Sexual Behavior Among Senior High School Students In Merauke District, Fenny Etrawati, Evi Martha, Rita Damayanti

Kesmas

Remaja usia 10-24 tahun merupakan kelompok yang rentan terhadap perilaku seksual pranikah, penyalahgunaan narkoba dan infeksi HIV/AIDS. Papua merupakan penyumbang angka HIV/AIDS terbesar di Indonesia. Untuk menanggulangi permasalahan tersebut Rutgers WPF membentuk suatu program intervensi kesehatan reproduksi remaja di tingkat sekolah menengah atas (SMA) yakni program Dunia Remajaku Seru! (DAKU!). Penelitian ini bertujuan untuk mengetahui determinan psikososial perilaku seksual berisiko pada siswa SMA di Kabupaten Merauke dengan menggunakan pendekatan potong lintang. Sampel berjumlah 1.364 siswa SMA kelas dua yang mendapatkan program DAKU!dan dilakukan proses pencocokan pada sekolah yang tidak mendapat program DAKU!. Analisis data meliputi analisis univariat, bivariat (uji kai …

Nurses’ Intention And Behavior In Reporting Adverse Event: Application Of Theory Of Planned Behavior, Ni Putu Ekayani, Viera Wardhani, Asih Tri Rachmi

Kesmas

Data menunjukkan bahwa secara global jumlah pelaporan insiden keselamatan pasien masih rendah, begitu juga di Rumah Sakit Baptis Batu, Jawa Timur. Penelitian ini bertujuan untuk mengetahui pengaruh antara sikap, norma subjektif, dan perceived behavioral control (PBC) terhadap niat dan untuk menentukan hubungan antara PBC dan niat terhadap perilaku perawat dalam melaporkan kejadian tidak diharapkan (KTD). Penelitian ini menggunakan pendekatan potong lintang dan dilakukan di Rumah Sakit Baptis Batu pada tanggal 16-31 Maret 2016. Pengambilan data dilakukan dengan menggunakan kuesioner yang dibagikan kepada 82 (dari 85) perawat yang bekerja di Rumah Sakit Baptis Batu. Data dianalisis menggunakan regresi linier berganda dan …

Risk Factors Of Premature Rupture Of Membrane, Maryuni Maryuni, Dedeh Kurniasih

Kesmas

Angka kematian ibu di Indonesia berdasarkan Survei Demografi dan Kesehatan Indonesia (SDKI) tahun 2012 sebanyak 359 per 100.000 kelahiran hidup. Penyebab kematian ibu tersebut masih didominasi oleh pendarahan, pre-eklampsia/eklampsia, dan infeksi. Salah satu penyebab infeksi adalah ketuban pecah dini (KPD). KPD dapat meningkatkan morbiditas dan mortalitas pada ibu dan anak. Insiden kejadian KPD sekitar 10,7% dari seluruh persalinan. Penelitian ini bertujuan untuk mengetahui faktor risiko kejadian KPD di Rumah Sakit Ibu dan Anak (RSIA) ANNISA Citeureup, Kabupaten Bogor tahun 2014. Penelitian ini merupakan penelitian analitik dengan rancangan penelitian kasus kontrol. Sampel terdiri dari 114 orang kasus ibu yang mengalami KPD …

Evaluation Of Momentum Male Sterilization Service Effectiveness As An Attempt To Reach Muri Record, Endah Winarni, Muhammad Dawam

Kesmas

Pencapaian Program KB di Sumatera Utara kurang menggembirakan. Total Fertility Rate Sumatera Utara (3,0) lebih tinggi dibandingkan nasional (2,6); dan prevalensi kontrasepsi (55,9 %) lebih rendah dibandingkan nasional (61,9%). Sebagai salah satu strategi peningkatan kesertaan KB, pelayanan momentum sterilisasi pria dikhawatirkan tidak memenuhi standar pelayanan karena dikaitkan dengan rekor MURI. Evaluasi ini bertujuan untuk menjelaskan kualitas pelaksanaan pelayanan dan kepuasan akseptor sterilisasi pria. Evaluasi bersifat kualitatif dan kuantitatif dilakukan secara potong lintang terhadap petugas KB, calon akseptor dan akseptor yang mendapat tindakan sterilisasi pada pelayanan momentum di 13 fasilitas kesehatan di Kota Medan, Sumatera Utara pada 23-24 Oktober 2012. Data …

Evaluation Of Progress Towards The Unaids 90-90-90 Hiv Care Cascade: A Description Of Statistical Methods Used In An Interim Analysis Of The Intervention Communities In The Search Study, Laura Balzer, Joshua Schwab, Mark J. Van Der Laan, Maya L. Petersen

U.C. Berkeley Division of Biostatistics Working Paper Series

WHO guidelines call for universal antiretroviral treatment, and UNAIDS has set a global target to virally suppress most HIV-positive individuals. Accurate estimates of population-level coverage at each step of the HIV care cascade (testing, treatment, and viral suppression) are needed to assess the effectiveness of "test and treat" strategies implemented to achieve this goal. The data available to inform such estimates, however, are susceptible to informative missingness: the number of HIV-positive individuals in a population is unknown; individuals tested for HIV may not be representative of those whom a testing intervention fails to reach, and HIV-positive individuals with a viral …

The Use Of Vital Statistics Data For Research Of Consequence: Birth Outcomes And Population Health In A Rural Region, Claudia Kozinetz, Shimin Zheng, Eunice Mogusu

ETSU Faculty Works

Objective: The Affordable Care Act (ACA) has influenced increasing interests in population health and population health outcomes. The purpose of this study was to exemplify the importance of using existing vital statistics data for understanding and monitoring health outcomes and consequentially health disparities at the population level. Data from birth records for two geographic regions from 2009-2014 were compared; low birth weight (LBW) and preterm delivery (PD) were used as surrogates for population health outcomes.

Methods: A population-based, multi-year, cross-sectional study design using a pooled dataset of birth records from Tennessee (TN) was the framework for the analyses. …

Neighborhood Environment And Falls Among Community-Dwelling Older Adults, Emily Joy Nicklett, Matthew C. Lohman Ph.D., Matthew Lee Smith

Faculty Publications

Background: Falls present a major challenge to active aging, but the relationship between neighborhood factors and falls is poorly understood. This study examined the relationship between fall events and neighborhood factors, including neighborhood social cohesion (sense of belonging, trust, friendliness, and helpfulness) and physical environment (vandalism/graffiti, rubbish, vacant/deserted houses, and perceived safety walking home at night). Methods: Data were analyzed from 9259 participants over four biennial waves (2006–2012) of the Health and Retirement Study (HRS), a nationally representative sample of adults aged 65 and older in the United States. Results: In models adjusting for demographic and health-related covariates, a one-unit …

It's All About Balance: Propensity Score Matching In The Context Of Complex Survey Data, David Lenis, Trang Q. ;Nguyen, Nian Dong, Elizabeth A. Stuart

Johns Hopkins University, Dept. of Biostatistics Working Papers

Many research studies aim to draw causal inferences using data from large, nationally representative survey samples, and many of these studies use propensity score matching to make those causal inferences as rigorous as possible given the non-experimental nature of the data. However, very few applied studies are careful about incorporating the survey design with the propensity score analysis, which may mean that the results don’t generate population inferences. This may be because few methodological studies examine how to best combine these methods. Furthermore, even fewer of the methodological studies incorporate different non-response mechanisms in their analysis. This study examines methods …

The Battle Against Malaria: A Teachable Moment, Randy K. Schwartz

Journal of Humanistic Mathematics

Malaria has been humanity’s worst public health problem throughout recorded history. Mathematical methods are needed to understand which factors are relevant to the disease and to develop counter-measures against it. This article and the accompanying exercises provide examples of those methods for use in lower- or upper-level courses dealing with probability, statistics, or population modeling. These can be used to illustrate such concepts as correlation, causation, conditional probability, and independence. The article explains how the apparent link between sickle cell trait and resistance to malaria was first verified in Uganda using the chi-squared probability distribution. It goes on to explain …

Estimating The Probability Of Clonal Relatedness Of Pairs Of Tumors In Cancer Patients, Audrey Mauguen, Venkatraman E. Seshan, Irina Ostrovnaya, Colin B. Begg

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

Next generation sequencing panels are being used increasingly in cancer research to study tumor evolution. A specific statistical challenge is to compare the mutational profiles in different tumors from a patient to determine the strength of evidence that the tumors are clonally related, i.e. derived from a single, founder clonal cell. The presence of identical mutations in each tumor provides evidence of clonal relatedness, although the strength of evidence from a match is related to how commonly the mutation is seen in the tumor type under investigation. This evidence must be weighed against the evidence in favor of independent tumors …

Further Advances For The Sequential Multiple Assignment Randomized Trial (Smart), Tianjiao Dai

Dissertations and Theses (Open Access)

ABSTRACT

FURTHER ADVANCES FOR THE SEQUENTIAL MULTIPLE ASSIGNMENT RANDOMIZED TRIAL (SMART)

Tianjiao Dai, M.S.

Advisory Professor: Sanjay Shete, Ph.D.

Sequential multiple assignment randomized trial (SMART) designs have been developed these years for studying adaptive interventions. In my Ph.D. study, I mainly investigate how to further improve SMART designs and optimize the interventions for each individual in the trial. My dissertation has focused on two topics of SMART designs.

1) Developing a novel SMART design that can reduce the cost and side effects associated with the interventions and proposing the corresponding analytic methods. I have developed a time-varying SMART design in …

Predicting Future Years Of Life, Health, And Functional Ability: A Healthy Life Calculator For Older Adults, Paula Diehr, Michael Diehr, Alice M. Arnold, Laura Yee, Michelle C. Odden, Calvin H. Hirsch, Stephen Thielke, Bruce Psaty, W Craig Johnson, Jorge Kizer, Anne B. Newman

UW Biostatistics Working Paper Series

Introduction

Planning for the future would be easier if we knew how long we will live and, more importantly, how many years we will be healthy and able to enjoy it. There are few well-documented aids for predicting our future health. We attempted to meet this need for persons 65 years of age and older.

Methods

Data came from the Cardiovascular Health Study, a large longitudinal study of older adults that began in 1990. Years of life (YOL) were defined by measuring time to death. Years of healthy life (YHL) were defined by an annual question about self-rated health, and …

On The Three Dimensional Interaction Between Flexible Fibers And Fluid Flow, Bogdan Nita, Ryan Allaire

Department of Mathematics Faculty Scholarship and Creative Works

In this paper we discuss the deformation of a flexible fiber clamped to a spherical body and immersed in a flow of fluid moving with a speed ranging between 0 and 50 cm/s by means of three dimensional numerical simulation developed in COMSOL . The effects of flow speed and initial configuration angle of the fiber relative to the flow are analyzed. A rigorous analysis of the numerical procedure is performed and our code is benchmarked against well established cases. The flow velocity and pressure are used to compute drag forces upon the fiber. Of particular interest is the behavior …

Correlation Of Positron Emission Tomography/Computed Tomography Scan With Smoking, Tumor Size, Stage And Differentiation In Head And Neck Cancer Patients, Jordan L. Pleitz, Partha Sinha, Emily V. Dressler, Rony K. Aouad

Otolaryngology--Head & Neck Surgery Faculty Publications

The goal of this study was to identify associations between positron emission tomography/computed tomography (PET/CT) maximum standardized uptake value (SUVmax) in patients presenting with head and neck squamous cell carcinoma (SCC) with tumor site, size, histologic differentiation, smoking, and diabetes. Charts of patients with oropharyngeal and laryngeal SCC who underwent ¹⁸F-fluorodeoxyglucose PET/CT scans were reviewed between May 2007 and August 2013. Statistical analyses included modeling log-transformed SUVmax values by tumor site, size, histologic differentiation, smoking status, and diabetes using unadjusted linear regressions. Differences were considered statistically significant for P< 0.05. A total of 111 patients (54 with oropharynx and 57 with larynx cancers) were included, 83 men and 28 women with an average age of 57.5 years old. There was a significantly higher pack-year smoking history (P = 0.005) in the larynx cancer group. While tumor …

Quantifying The Totality Of Treatment Effect With Multiple Event-Time Observations In The Presence Of A Terminal Event From A Comparative Clinical Study, Brian Claggett, Lu Tian, Haoda Fu, Scott D. Solomon, L. J. Wei

Harvard University Biostatistics Working Paper Series

To evaluate the totality of one treatment's benefit/risk profile relative to an alternative treatment via a longitudinal comparative clinical study, the timing and occurrence of multiple clinical events are typically collected during the patient's followup. These multiple observations reflect the patient's disease progression/burden over time. The standard practice is to create a composite endpoint from the multiple outcomes, the timing of the occurrence of the first clinical event, to evaluate the treatment via the standard survival analysis techniques. By ignoring all events after the composite outcome, this type of assessment may not be ideal. Various parametric or semi-parametric procedures have …