Comparative safety of adding serotonin and norepinephrine reuptake inhibitors (SNRIs) versus nonsteroidal anti‐inflammatory drugs (NSAIDs) to short‐acting opioids for non‐malignant pain in nursing homes.

Background: The comparative safety of serotonin and norepinephrine reuptake inhibitors (SNRIs) as adjuvants to short‐acting opioids in older adults is unknown even though SNRIs are commonly used. We compared the effects of SNRIs versus nonsteroidal anti‐Inflammatory drugs (NSAIDs) on delirium among nursing home residents when SNRIs or NSAIDs were added to stable regimens of short‐acting opioids. Methods: Using 2011–2016 national Minimum Data Set (MDS) 3.0 and Medicare claims data to implement a new‐user design, we identified a cohort of nursing home residents receiving short‐acting opioids who initiated either an SNRI or an NSAID. Delirium was defined from the Confusion Assessment Method in MDS 3.0 assessments and ICD9/10 codes using Medicare hospitalization claims. Propensity score matching balanced underlying differences for initiating treatments on 39 demographic and clinical characteristics (nSNRIs = 5350; nNSAIDs = 5350). Fine and Gray models provided hazard ratios (HRs) and 95% confidence intervals (CIs) adjusting for the competing risk of death. Results: Hydrocodone was the most commonly used short‐acting opioid (48%). Residents received ~23 mg daily oral morphine equivalent at the time of SNRIs/NSAIDs initiation. The majority were women, non‐Hispanic White, and aged ≥75 years. There were no differences in any of the confounders after propensity matching. Over 1 year, 10.8% of SNRIs initiators and 8.9% of NSAIDs initiators developed delirium. The rate of delirium onset was similar in SNRIs and NSAID initiators (HR(delirium in nursing home or hospitalization for delirium):1.10; 95% CI: 0.97–1.24; HR(hospitalization for delirium): 1.06; 95% CI: 0.89–1.25), and were similar regardless of baseline opioid daily dosage. Conclusions: Among nursing home residents, adding SNRIs to short‐acting opioids does not appear to increase risk of delirium relative to initiating NSAIDs. Understanding the comparative safety of pain regimens is needed to inform clinical decisions in a medically complex population often excluded from clinical research. [ABSTRACT FROM AUTHOR]