Opioid Initiation and the Hazard of Falls or Fractures Among Older Adults with Varying Levels of Central Nervous System Depressant Burden.

BACKGROUND

Co-prescription of opioids with other central nervous system (CNS) depressants is common but the combination may increase the risk for adverse events such as falls and fractures, particularly among older adults. We explored the risk of fall- or fracture-related hospital visits after opioid initiation among older adults with varying degrees of concomitant CNS depressant burden.

METHODS

We used population-based administrative health data from Ontario, Canada, to examine the relationship between hospital visits for falls or fractures at different levels of CNS burden among individuals aged 66 and older who started prescription opioids between March 1, 2008, and March 31, 2019. For comparison, we identified individuals starting prescription non-steroidal anti-inflammatory drugs (NSAIDs). The outcome was a hospital visit for falls or fractures within 14 days after starting analgesic therapy. We stratified the cohort according to additional CNS burden: none, low (one concurrent CNS depressant drug class) and high (≥ 2 concurrent CNS depressant classes) on the index date. We balanced opioid and NSAID recipients using inverse probability of treatment weighting and reported weighted hazard ratios from Cox proportional hazards models. We then used pairwise comparisons to determine differences between hazard ratios at different levels of CNS burden.

RESULTS

The cohort included 1,066,692 older adults, with 562,692 new opioid recipients and 504,000 new NSAID recipients. Among opioid recipients, 83 % had no additional CNS burden, 13 % had low burden and 4 % had high burden. The short-term rate of falls or fractures for new opioid recipients increased by CNS burden from 97 per 1000 person-years (no burden) to 233 per 1000 person-years (high CNS burden). Opioid recipients had a similarly elevated hazard of falls or fractures within each CNS burden level compared to NSAID recipients (adjusted hazard ratio [aHR] 1.62, 95 % CI 1.50-1.76 for no burden; aHR 1.69, 95 % CI 1.45-1.97 for low burden; aHR 1.40, 95 % CI 1.08-1.82 for high burden).

CONCLUSION

Among older adults, initiation of opioids is associated with an increased hazard of falls; however, this hazard is not modified by different levels of CNS depressant burden. This suggests that it remains important for physicians, patients, and caregivers to be vigilant when starting new opioid therapy regardless of other CNS medications taken concurrently.