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Janet Wittes

Publications and source records attributed to Janet Wittes.

6 recordsLinked to original sources
PubMed2026

Subgroups and Special Populations in Heart Failure Clinical Trials: Insights From the HFC-ARC Expert Consensus Panel.

In the evolving landscape of heart failure (HF) management, the identification and analysis of subgroups and special populations within clinical trials are crucial for enhancing clinical decision-making, guiding further research, and understanding heterogeneity in study outcomes. This expert consensus document results from the collaborative efforts of the Heart Failure Collaboratory and the Heart Failure Collaboratory Academic Research Consortium, which brought together stakeholders from academia, industry, the U.S. Food and Drug Administration, and patient representatives. The purpose of this assembly was to propose standardized definitions and critical endpoint considerations essential for shaping the design and conduct of clinical trials for drugs and devices in the field of HF. In this context, we propose definitions and endpoints for specific subgroups and special populations in the spectrum of HF. We enhanced the precision, efficacy, and applicability of clinical research and promote more "personalized" approaches to interpretation of clinical trials. Furthermore, we explore the burgeoning field of gene therapy as a promising avenue for addressing the genetic basis of certain cardiomyopathies within these specialized patient groups. We focus especially on methodological considerations for subgroup analyses in large-scale trials, highlighting the importance of proper interpretation of subgroups and best practices for identifying heterogeneity suggestive of differential treatment effects, including when these analyses should be considered hypothesis-generating and requiring subsequent validation. We advocate for a methodical approach to clinical trial design, one that prioritizes the strategic identification of subgroups and employs appropriate statistical methodologies to ensure the reliability and clinical relevance of findings. Through this lens, we envision a pathway toward more personalized and effective treatments for HF, ultimately aiming to improve patient outcomes by leveraging the insights garnered from meticulously designed and comprehensively analyzed clinical trials.

Humans↗
PubMed2002

On changing a long-term clinical trial midstream.

Clinical triallists are often reluctant to alter the protocol or the design of an ongoing study in part because of concern that changes may affect the integrity of the study. This paper encourages considering changes in long-term clinical trials when the medical environment changes or when the accruing data from the trial lead to questioning the assumptions underlying the original design. One must make such changes in a way that will not cast doubt on the integrity of the trial. An important aspect of the design is choice of sample size. Methodology for sample size recalculation has matured over the decade. Several techniques are now available for the usual types of endpoints - continuous, discrete and time-to-failure - as well as for longitudinal analysis. Published papers describe the choices of variance at the time of recalculation, approaches to estimation and testing at the end of the study, and the time of recalculation. In a study with a sponsor, a Data Safety Monitoring Board (DSMB) and an Executive Committee, one or more of these three groups is responsible for recommending increases in sample size when the accruing data indicate that the assumed variance underestimated the true variance. Sometimes a statistician independent of all three bodies performs the relevant calculations and sends the recommendation to the sponsor. This paper argues that the DSMB should not generally be the responsible body because knowledge of treatment effect can place it in an uncomfortable position.

Aspirin↗
PubMed2002

Cost-effectiveness of gemfibrozil for coronary heart disease patients with low levels of high-density lipoprotein cholesterol: the Department of Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial.

BACKGROUND: Although numerous clinical trials and economic analyses have established the efficacy and cost-effectiveness of lowering cholesterol for the prevention of coronary heart disease, there are few data on the role of raising high-density lipoprotein cholesterol (HDL-C) levels and lowering triglyceride levels. The US Department of Veterans Affairs (VA) Cooperative Studies Program HDL-C Intervention Trial (VA-HIT) was a multicenter, randomized trial of gemfibrozil, an agent that raised HDL-C levels and lowered triglyceride levels, yet had no effect on low-density lipoprotein cholesterol (LDL-C) levels. The study showed that gemfibrozil therapy significantly reduced major cardiovascular events (cardiovascular death, myocardial infarction, and stroke) in patients with coronary heart disease, low HDL-C levels, and low LDL-C levels. OBJECTIVE: To report the results of a cost-effectiveness study based on the results of the VA-HIT. METHODS: The cost per year of life gained with gemfibrozil therapy was calculated. Hazard functions were estimated, and the resulting probabilities were used in a Markov model simulation to estimate the effect of gemfibrozil on life expectancy and costs over a simulated lifetime. Sensitivity analyses were used to account for uncertainty. RESULTS: Using the prices of gemfibrozil that were negotiated by the VA, gemfibrozil was cost saving. Using drug prices found outside the VA, a quality-adjusted life-year saved by gemfibrozil therapy cost between $6300 and $17 100. CONCLUSIONS: Gemfibrozil reduces major cardiovascular events in male coronary heart disease patients with low levels of HDL-C and low levels of LDL-C and would result in cost saving at annual drug costs of $100 or less in 1998 dollars. Even at the higher drug prices represented by the average wholesale price in the United States, the cost of a life-year saved is well below the threshold that would be deemed cost-effective. To our knowledge, this is the first economic analysis based on clinical trial data to assess the cost-effectiveness of raising HDL-C levels and lowering triglyceride levels in a setting in which LDL-C levels were not lowered.

Aged↗
PubMed2001

Baseline Characteristics and Early Blood Pressure Control in the CONVINCE Trial.

-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. We wanted to assess BP control during the first 2 years and to describe the baseline characteristics of patients enrolled in the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) Study, an international clinical trial that compares outcomes in hypertensive patients randomized to initial treatment with either controlled-onset extended-release verapamil or the investigator's choice of atenolol or hydrochlorothiazide. At randomization, BP was <140/90 mm Hg in only 20.3% of the 16 602 subjects (average+/-SD age 65.6+/-7.4 years; 56% women, 84% white/7% black/7% Hispanic). The average BP at enrollment was 148/85 mm Hg for patients taking BP medications (n=13 879) and 161/94 mm Hg for previously untreated patients (n=2723). After medication titration, with a transtelephonic computer that recommended an increase in the dose or number of antihypertensive agents whenever the BP was 140/90 mm Hg, 84.8% of the subjects attained the goal BP. During 2 years of treatment, BP control was maintained in 67% to 69% of the subjects (69% to 71% for systolic BP of <140 mm Hg and 90% for diastolic BP of <90 mm Hg). These data suggest that the control of systolic BP is more difficult than the control of diastolic BP. The US national goal of having 50% of hypertensives with a BP of <140/90 mm Hg may be achievable if a forced titration strategy is used. Interested investigators, free care and medications, and well-educated subjects may make the attainment of such a goal easier in the CONVINCE study than in the general population.

Journal Article↗
PubMed2001

Experience collecting interim data on mortality: an example from the RALES study.

INTRODUCTION: The Randomized Aldactone Evaluation Study (RALES) randomized 822 patients to receive 25 mg spironolactone daily and 841 to receive placebo. The primary endpoint was death from all causes. Randomization began on March 24, 1995; recruitment was completed on December 31, 1996; follow-up was scheduled to continue through December 31, 1999. Evidence of a sizeable benefit on mortality emerged early in the RALES. The RALES data safety monitoring board (DSMB), which met semiannually throughout the trial, used a prespecified statistical guideline to recommend stopping for efficacy. At the DSMB's request, its meetings were preceded by an 'endpoint sweep', that is, a census of all participants to confirm their vital status. METHODS: We used computer simulation to evaluate the effect of the sweeps. RESULTS: The sweeps led to an estimated 5 to 8% increase in the number of reported deaths at the fourth and fifth interim analyses. The data crossed the statistical boundary at the fifth interim analysis. If investigators had reported all deaths within the protocol-required 24-h window, the DSMB might have recommended stopping after the fourth interim analysis. DISCUSSION: Although endpoint sweeps can cause practical problems at the clinical centers, sweeps are very useful if the intervals between patient visits or contact are long or if endpoints require adjudication by committee, reading center, or central laboratory. CONCLUSION: We recommend that trials with interim analyses institute active reporting of the primary endpoints and endpoint sweeps.

Journal Article↗