Sample-size formula for clustered survival data using weighted log-rank statistics

• 成果类型: Article
• 署名作者: Gangnon, RE; Kosorok, MR
• 署名单位: University of Wisconsin System; University of Wisconsin Madison; University of Wisconsin System; University of Wisconsin Madison
• 刊物名称: BIOMETRIKA
• ISSN/ISSBN: 0006-3444
• DOI: 10.1093/biomet/91.2.263
• 发表日期: 2004
• 页码: 263275
• 关键词: tests; time

摘要

We present a simple sample-size formula for weighted log-rank statistics applied to clustered survival data with variable cluster sizes and arbitrary treatment assignments within clusters. This formula is based on the asymptotic normality of weighted log-rank statistics under certain local alternatives in the clustered data context. We also provide consistent variance estimators. The derived sample-size formula reduces to Schoenfeld's (1983) formula for cases of no clustering or independence within clusters. Simulation results verify control of the Type I error and accuracy of the sample-size formula. Use of the sample-size formula in an event-driven clinical trial design is illustrated using data from the Early Treatment Diabetic Retinopathy Study.