Objective: To analyze the relationship between nonunion of humeral shaft fractures and nonsteroidal antiinflammatory drug (NSAID) exposure in older adults.
Methods: A cohort of 9,995 patients with humeral shaft fractures was identified using diagnosis and procedure codes from a Medicare database of >500,000 patients. Prescription NSAID as well as prescription opioid use was assessed from pharmacy claims data for 3 30-day periods immediately after the initial fracture. Nonunion was defined by the presence of procedure codes for repair of nonunion 90-365 days after the index fracture. We examined the association between NSAIDs and nonunion using multivariate Cox proportional hazards models.
Results: Of the 9,995 humeral shaft fractures, 105 patients developed nonunions (1.1%), and 1,032 (10.3%) were exposed to NSAIDs in the 90 days after fracture. NSAID exposure within the first 90 days was significantly associated with nonunion (relative risk [RR] 3.7, 95% confidence interval [95% CI] 2.4-5.6). When indicators for exposure to NSAIDs during each of the 3 30-day windows were placed into the same multivariate model, only the period 61-90 days post-fracture was significantly associated with nonunion (RR 3.9, 95% CI 2.0-6.2). We observed a similar association between opioids and nonunion, with exposure to opioids between 61 and 90 days associated with nonunion (RR 2.7, 95% CI 1.5-5.2), but exposure to opioids during neither of the 2 earlier 30-day periods significantly associated with nonunion.
Conclusion: We found that exposure to nonselective NSAIDs or opioids in the period 61-90 days after a humeral shaft fracture was associated with nonunion. Although these associations may be causal, they are more likely to reflect the use of analgesics by patients with painful nonhealing fractures.