Factors associated with long-term benzodiazepine and Z-drug use across the lifespan and 5-year temporal trajectories among incident users: a Swedish nationwide register-based study

PURPOSE: Despite being discouraged by guidelines, long-term use of benzodiazepines and related Z-drugs (BZDR) remains frequent in the real-world. An improved understanding of factors associated with the transition from new to long-term BZDR use and of temporal BZDR use trajectories is needed. We aimed to assess the proportion of long-term BZDR use (> 6 months) in incident BZDR-recipients across the lifespan; identify 5-year BZDR use trajectories; and explore individual characteristics (demographic, socioeconomic and clinical) and prescribing-related factors (pharmacological properties of the initial BZDR, prescriber’s healthcare level, and concurrent dispensing of other medications) associated with long-term BZDR use and distinct trajectories. METHODS: Our nationwide register-based cohort included all BZDR-recipients in Sweden with first dispensation in 2007–2013. Trajectories of BZDR use days per year were built using group-based trajectory modelling. Cox regression and multinomial logistic regression were fitted to assess the predictors of long-term BZDR use and trajectories’ membership. RESULTS: In 930,465 incident BZDR-recipients, long-term use increased with age (20.7%, 41.0%, and 57.4% in 0–17, 18–64, and ≥ 65-year-olds, respectively). Four BZDR use trajectories emerged, labelled ‘discontinued’, ‘decreasing’, ‘slow decreasing’ and ‘maintained’. The proportion of the ‘discontinued’ trajectory members was the largest in all ages, but reduced from 75.0% in the youths to 39.3% in the elderly, whereas the ‘maintained’ increased with age from 4.6% to 36.7%. Prescribing-related factors, in particular multiple BZDRs at initiation and concurrent dispensing of other medications, were associated with increased risks of long-term (vs short-term) BZDR use and developing other trajectories (vs ‘discontinued’) in all age groups. CONCLUSIONS: The findings highlight the importance of raising awareness and providing support to prescribers to make evidence-based decisions on initiating and monitoring BZDR treatment across the lifespan. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00228-023-03515-2.