Prevention holds the promise of maintaining good health by testing, diagnosing, and treating conditions before they cause symptoms. However, prevention can harm as well as help when tests or treatments for asymptomatic conditions cause immediate complications. “Lag time to benefit” is defined as the time between a preventive intervention (when complications and harms are most likely) to the time when improved health outcomes are seen.1 Just as different interventions have different magnitudes of benefit, different preventive interventions have different lag times to benefit, ranging from 6 months for statin therapy for secondary prevention to more than 10 years for prostate cancer screening.2 Many standardized measures such as relative risk, odds ratio, and absolute risk reduction quantify the magnitude of benefit (“How much will it help?”). However, the measures and methodologies to calculate a lag time to benefit (“When will it help?”) are underdeveloped and often not reported.
Lee SJ, Leipzig RM, Walter LC. Incorporating Lag Time to Benefit Into Prevention Decisions for Older Adults. JAMA. 2013;310(24):2609–2610. doi:10.1001/jama.2013.282612