A Survival Guide for Drug Survival Studies in Dermatology – Methodological Approaches and Best Practices

The expanding therapeutic landscape for inflammatory skin diseases, combined with rising healthcare costs, has increased the need for a comprehensive method to assess and compare treatment performance in daily practice care. In this context, drug survival, the time a patient remains on a given treatment, has gained increasing attention in dermatology, as it comprehensively reflects treatment effectiveness, safety, and patient and clinician preferences. However, methodological approaches and reporting practices vary considerably across drug survival studies in dermatology. In this article, we aim to provide an updated and comprehensive guide for clinical researchers on drug survival methodology, offering recommendations for performing, reporting, and interpreting drug survival analyses in a standardized manner, while highlighting best practices within dermatology. We provide guidance on fundamental concepts of drug survival analysis, including Kaplan–Meier curves, reporting standards, censoring, stratification, regression analyses, and sample size calculations. Additionally, to further enhance the quality of analyses, we discuss advanced topics such as restricted mean survival time, competing risks, time-dependent effects and covariates, and meta-analyses of drug survival data. Key concepts will be illustrated using a synthetic dataset, comprising patients with psoriasis treated with biologics, complemented by references to published studies that clarify relevant methodological concepts and provide real-world dermatological examples.