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Full-Text Articles in Biostatistics
Survival Versus Years Of Healthy Life; Which Is More Powerful As A Study Outcome?, Paula Diehr
Survival Versus Years Of Healthy Life; Which Is More Powerful As A Study Outcome?, Paula Diehr
Paula Diehr
Studies of interventions that are intended to improve patients' health are often evaluated with survival as the primary outcome, even when a measure adjusted for quality of survival, such as years of healthy life (YHL), would seem more appropriate. The purpose of this article is to determine whether studies based on survival are more or less powerful than studies based on YHL in clinical trials where either measure might be appropriate. We used data from the Cardiovascular Health Study (CHS) to estimate the sample size that would be needed in studies of 156 different health conditions, for the two outcome …
Effect Size And Power For Clinical Trials Using Years Of Healthy Life As The Primary Endpoint, Paula Diehr
Effect Size And Power For Clinical Trials Using Years Of Healthy Life As The Primary Endpoint, Paula Diehr
Paula Diehr
Some clinical trials perform repeated measurements on patients over time, plot those measures against time, and summarize the results in terms of the area under the curve. If the measured variable is health status, the summary outcome is sometimes referred to as years of healthy life (YHL), or quality-adjusted life years (QALY). This paper investigates some theoretical and practical aspects of randomized trials designed to assess measures such as YHL. We first derived algebraic expressions for the effect size of YHL measures under several theoretical models of the treatment's effect on health. We used these expressions to examine how the …