Background: Although highly active antiretroviral therapy (HAART) has improved HIV survival, some patients receiving therapy are still dying. This analysis was conducted to identify factors associated with increased risk of post-HAART mortality.
Methods: We evaluated baseline (prior to HAART initiation) clinical, demographic and laboratory factors (including CD4+ count and HIV RNA level) for associations with subsequent mortality in 1,600 patients who began HAART in a prospective observational cohort of HIV-infected U.
Background: Among HIV-infected persons initiating highly active antiretroviral therapy (HAART), early CD4+ lymphocyte count increases are well described. However, whether CD4+ levels continue to increase or plateau after 4-6 years is controversial.
Methods: To address this question and identify other determinants of CD4+ response, we analyzed data for 1,846 persons from a prospective HIV military cohort study who initiated HAART, who had post-HAART CD4+ measurements, and for whom HIV seroconversion (SC) date was estimated.
Methods: The self-reported number of children was compared for men and women from the National Epidemiologic Survey of Alcoholism and Related Conditions Survey (NESARC). Subjects with a diagnosis of major depressive disorder or bipolar disorder were compared to those without an axis I disorder. The effect of age, gender, marriage and diagnostic status on number of children was completed using multivariate analyses.
View Article and Find Full Text PDFProstate cancer is the most frequently diagnosed cancer in men. Whereas chronic calorie restriction (CCR) delays prostate tumorigenesis in some rodent models, the impact of intermittent caloric restriction (ICR) has not been determined. Here, transgenic adenocarcinoma of the mouse prostate (TRAMP) mice were used to compare how ICR and CCR affected prostate cancer development.
View Article and Find Full Text PDFBackground: Many clinical trials have multiple outcomes. Formal interim monitoring guidelines that take account of multiple outcomes can be useful to Data Monitoring Committees (DMC). Previous research has focused on marginal criteria that control the overall type I error for bivariate endpoints corresponding to efficacy and safety.
View Article and Find Full Text PDFBackground: Most methods of sample size calculations for survival trials adjust the estimated outcome event rates for noncompliance based on the assumption that non-compliance is independent of the risk of the outcome event although there has been published evidence that noncompliers are often at a higher risk than compliers. More recent work has started to consider the situations of informative noncompliance and different risks for noncompliers. However, the possibility of a time-varying association between noncompliance and risk has been ignored.
View Article and Find Full Text PDFJ Biopharm Stat
December 2005
A method is proposed for the estimation of drug or toxicity potencies using in vitro data. A typical experiment in cancer research is presented where cells from a tumor-derived cell line were deposited as fixed volumes in 12-well cell culture plates. After waiting for 72 hours (for further growth), the wells were exposed to different concentrations of a drug and, at the end of the experiment, the numbers of surviving cells were counted.
View Article and Find Full Text PDFEnviron Monit Assess
September 2005
Survival analysis methodologies provide novel approaches for forest mortality analysis that may aid in detecting, monitoring, and mitigating of large-scale forest health issues. This study examined survivor analysis for evaluating a regional forest health issue - Missouri oak decline. With a statewide Missouri forest inventory, log-rank tests of the effects of covariates on the survivor function and equality of the survivor function among classes were conducted for selected oak species.
View Article and Find Full Text PDFObjective: To examine regional differences in the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) trial.
Design: Double-blind, randomized, international clinical trial.
Setting: Six hundred and sixty-one clinical centers in 15 countries.
A method is proposed for the evaluation of in vitro experiments for combination chemotherapy, a new and growing area of cancer research. We first describe and review a popular graphical device called an isobologram. We then propose a statistical framework, a simple experimental design, and a statistical test for use with this widely accepted methodology.
View Article and Find Full Text PDFTwo independent groups recently published data comparing pulsatile luteinizing hormone (LH) release between depressed and control women. Despite similar populations and LH sampling frequency, they reached different conclusions: Meller et al. [Am.
View Article and Find Full Text PDFFirst vaccines are traditionally licensed after showing favourable results from phase III efficacy trials. Subsequent competing vaccines, however, have been licensed primarily on the basis of immunogenicity data rather than clinical efficacy. Focusing on pneumococcal vaccines where optical densities are measured and serum antibody concentrations are 'estimated' (from a statistical model) using an immunoglobulin (IgG) enzyme-linked immunosorbent assay (ELISA), the focus of this paper will centre on two highly related issues: the determination of an upper limit for quality control used in the assay methodology (let us call it the maximum tolerated limit or MTL) and the identification of vaccine responders.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
August 2003
Purpose: To evaluate sampling strategies used to estimate survival after uveal malignant melanoma that exclude some patients who would be censored from the analysis.
Methods: Simulation was performed on a population-based data set of 133 patients who had an eye enucleated because of uveal melanoma. One thousand bootstrap samples of 80 patients were drawn, without replacement, according to three sampling strategies: a random draw (conventional strategy), a draw limited to patients who died of the tumor or survived at least 10 years without metastasis ("late-censoring" strategy), and a draw modified so that 40 patients died of melanoma and others survived at least 10 years without metastasis ("fifty-fifty" strategy).
Context: Hypertensive patients are often given a calcium antagonist to reduce cardiovascular disease risk, but the benefit compared with other drug classes is controversial.
Objective: To determine whether initial therapy with controlled-onset extended-release (COER) verapamil is equivalent to a physician's choice of atenolol or hydrochlorothiazide in preventing cardiovascular disease.
Design, Setting, And Participants: Double-blind, randomized clinical trial conducted at 661 centers in 15 countries.
Pulse detection algorithms and spectral analysis are the two most common methods for analysing pulsatile hormone data. We compared a popular high quality pulse detection algorithm (CLUSTER) to spectral analysis on a data set comparing luteinizing hormone data in depressed and control women. For these data, periodogram analysis methods, in particular Fisher's periodicity test, were superior in distinguishing the groups.
View Article and Find Full Text PDFAlthough a potential relationship between depression and infertility has been described throughout history, only recently has this topic been subjected to systematic investigation, and the literature is often confusing. The present study uses well-established structured psychiatric interviews--Structured Clinical Interview for DSM-III-R (SCID), Beck and Family History-Research Diagnostic Criteria (Fh-RDC)--to investigate the prevalence of major depression in a small group of women with infertility of unknown origin, and a community control sample. There were significantly more women with current depression or a history of depression in the infertile group, and of these women the majority experienced their first depressive episode prior to their diagnosis of infertility.
View Article and Find Full Text PDFAlthough high vegetable intakes have been associated with a lower risk of colorectal cancer, this relation is less well established for the precursor lesions, adenomatous polyps. With a case-control design involving adenomatous polyp cases (n = 564), colonoscopy-negative controls who were polyp free at colonoscopy (n = 682), and community controls (n = 535), this 1991-1994 Minnesota Cancer Prevention Research Unit study investigated the relation between fruit and vegetable consumption and first incident adenomatous polyps. Dietary intake was assessed using a food frequency questionnaire.
View Article and Find Full Text PDF-Blood pressure (BP) control rates around the world are suboptimal. Part 2 of the National Health and Nutrition Educational Survey (NHANES) III indicates that only 27.4% of hypertensive Americans aged 18 to 74 years have a BP of <140/90 mm Hg.
View Article and Find Full Text PDFPsychoneuroendocrinology
April 2001
In order to examine HPG axis regulation in women with major depression, luteinizing hormone (LH) pulsativity was studied in 26 depressed and 24 normal women. Blood was sampled every 10 min for an 8-h period during the first week of their menstrual cycle. LH pulsatile release was analyzed using the computerized cluster analysis algorithm of Veldhuis and Johnson and spectral analysis.
View Article and Find Full Text PDFThe Treatment of Mild Hypertension Trial was a randomized, double-blind clinical trial conducted from 1986 to 1992 comparing the efficacy of six antihypertensive treatment regimens in 902 participants with stage I hypertension. To satisfy a secondary objective of the study, follow-up information on mortality and cardiovascular morbidity was collected. For this objective the aim was to ascertain the vital and cardiovascular event status as of the last day of the trial.
View Article and Find Full Text PDFObjective: To test the effect of daily supplemental calcium on serum total and high-density lipoprotein cholesterol (HDL-C) levels and blood pressure in adults.
Design: Randomized, double-blind, placebo-controlled clinical trial; adjunct study to a trial of calcium and colon cell proliferation in patients with sporadic adenoma.
Setting: Outpatient clinic.
Cancer Epidemiol Biomarkers Prev
January 1999
Arylamine N-acetyltransferase 2 (NAT2) is involved in both the detoxification and bioactivation of carcinogenic arylamines and other mutagens. This enzyme is polymorphic, and the fast and slow phenotypes are thought to be risk factors for colon and bladder cancer, respectively. Here, we report on a case-control study of adenomatous and hyperplastic polyps, with particular attention to tobacco smoking, a known risk factor for adenomas, and polymorphisms of NAT2.
View Article and Find Full Text PDFThe Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) Trial is a randomized, prospective, double-blind, parallel-group, two-arm, actively controlled, multicenter, international 5-year clinical trial involving 15,000 patients. CONVINCE will compare the incidence of fatal or nonfatal myocardial infarction (MI), fatal or nonfatal stroke, or cardiovascular-disease-related death in two antihypertensive treatment regimens. One treatment arm begins with controlled onset-extended release (COER)-verapamil, which has its major antihypertensive effect 6-12 hours after administration.
View Article and Find Full Text PDFCancer Epidemiol Biomarkers Prev
December 1997
Colorectal epithelial cell proliferative kinetics are altered in patients at increased risk for colon cancer: proliferation rates [labeling index (LI)] are higher and there is a shift of the proliferative zone from one confined to the lower 60% of the colonic crypt to one that includes the entire crypt (higher phi(h)). To assess factors associated with LI and phi(h), we performed a cross-sectional analysis using baseline rectal mucosal biopsies from sporadic adenoma patients participating in a chemoprevention trial. Biopsies (taken without preparatory cleansing) were taken 10 cm above the level of the anus, and proliferation was assessed by detection of endogenous S-phase-associated proliferating cell nuclear antigen by immunohistochemical methods.
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