Abstract
Nonbenzodiazepine hypnotics ("Z-drugs") are prescribed for insomnia but might increase the risk of motor vehicle crash (MVC) among older adults through prolonged drowsiness and delayed reaction times. We estimated the effect of initiating Z-drug treatment on the 12-week risk of MVC in a sequential target trial emulation. After linking New Jersey driver licensing and police-reported MVC data to Medicare claims, we emulated a new target trial each week (July 1, 2007, to October 7, 2017) in which Medicare fee-for-service beneficiaries were classified as Z-drug-treated or untreated at baseline and followed for an MVC. We used inverse probability of treatment and censoring-weighted pooled logistic regression models to estimate risk ratios (RRs) and risk differences with 95% bootstrap confidence limits (CLs). There were 257 554 person-trials, of which 103 371 were Z-drug-treated and 154 183 untreated, giving rise to 976 and 1249 MVCs, respectively. The intention-to-treat RR was 1.06 (95% CL, 0.95-1.16). For the per-protocol estimand, there were 800 MVCs and 1241 MVCs among treated and untreated person-trials, respectively, suggesting a reduced MVC risk (RR, 0.83; 95% CL, 0.74-0.92) with sustained Z-drug treatment. Z-drugs should be prescribed to older patients judiciously but not withheld entirely over concerns about MVC risk. This article is part of a Special Collection on Pharmacoepidemiology.