Journal
JOURNAL OF CLINICAL EPIDEMIOLOGY
Volume 65, Issue 9, Pages 940-945Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/j.jclinepi.2012.02.012
Keywords
Clinical trials; Surrogate markers; Patient-important outcomes; Treatment effect; Biostatistics; Methodology
Ask authors/readers for more resources
Objective: Surrogate markers are often used in clinical trials if too much time or expense is involved to observe the effect of treatment on patient-important outcomes. We wished to estimate the ultimate effects of treatment when randomized trials have addressed only a surrogate marker, and additional, independent studies evaluate the association between the surrogate and the final outcome. Study Design and Setting: We show how to calculate the overall effect of treatment on a final outcome, together with its standard error and confidence interval. The methods are illustrated with data on the effect of therapy on hepatitis B seroconversion, a surrogate marker, and its association with patient-important outcomes (cirrhosis and liver cancer). Results: We find that the effect of treatment on the final outcome may be small even if there are strong associations between treatment and the surrogate and between the surrogate and the patient-important outcome. Conclusion: Apparently, robust treatment effects on surrogates are likely to lead to small and uncertain effects on patient-important outcomes. We should be cautious in advising patients to adopt a therapy when compelling evidence is restricted to its impact on surrogate outcomes, particularly if that therapy may be toxic or otherwise cause harms. (c) 2012 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available