Age-Related Risk of Serious Fall Events and Opioid Analgesic Use.

Importance:Opioid analgesics may be associated with increased risk of falls, particularly among older adults. Objective:To quantify the age-related risk of serious fall events among adults prescribed opioids by opioid exposure, time from initiation, and daily dose. Design, Setting, and Participants:This population-based cohort study conducted in New South Wales, Australia, used data linking national pharmaceutical claims to national and state datasets, including information on sociodemographic characteristics, clinical characteristics, medicines use, health services utilization, and mortality (POPPY II study). It included adults (18 years or older) who initiated prescription opioid treatment, which was defined as no prior dispensing during the preceding 365 days, between January 1, 2005, and December 31, 2018. Data were analyzed from February to June 2023. Exposure:Time-dependent periods of opioid exposure were evaluated from dispensing records. Main Outcome and Measures:Serious fall events identified from emergency department, hospitalization, and mortality records. Negative binomial models were used to assess associations between time-dependent opioid exposure (overall, by time from initiation, and by dose), age, and risk of fall events. Models were adjusted for known fall risk factors, including other fall risk-increasing drugs, frailty risk, and prior serious fall events. Results:The cohort comprised 3 212 369 individuals who initiated prescription opioid treatment (1 702 332 women [53%]; median [IQR] age at initiation, 49 [32-65] years). Overall, 506 573 serious fall events were identified, including 5210 fatal falls. During exposure to opioids, the risk of serious fall events was elevated among all age groups; compared with the group aged 18 to 44 years, this risk was highest among those 85 years or older (adjusted incident rate ratio, 6.35; 95% CI, 6.20-6.51). Across all age groups, the first 28 days following opioid initiation was a time of increased serious fall risk; this risk increased with age. Among individuals aged 18 to 84 years, associations were identified between higher daily opioid doses and serious fall events. Conclusions and Relevance:The results of this cohort study suggest that prescription opioids were associated with increased risk of serious fall events among adults of all ages, with individuals 85 years or older at greatest risk. These risks should be considered when prescribing opioids, particularly for individuals with preexisting risk factors or when opioids are prescribed at higher doses. Targeted falls prevention efforts may be most effective within the first month following opioid initiation.