Time-to-Cessation of Postoperative Opioids: A Population-Level Analysis of the Veterans Affairs Health Care System.

Objective. This study aims to determine 1) the epidemiology of perioperative opioid use; and 2) the association between patterns of preoperative opioid use and time-to-cessation of postoperative opioids. Design. Retrospective, cohort study. Setting. National, population-level study of Veterans Healthcare Administration (VHA) electronic clinical data. Subjects. All VHA patients (n564,391) who underwent surgery in 2011, discharged after stays of ≥1 day, and receiving ≥1 opioid prescription within 90 days of discharge. Methods. Patients' preoperative opioid use were categorized as 1) no opioids, 2) tramadol only, 3) shortacting (SA) acute/intermittent (≤ 90 days fill), 4) SA chronic (> 90 days fill), or 5) any long-acting (LA). After defining cessation as 90 consecutive, opioidfree days, the authors calculated time-to-opioid-cessation (in days), from day 1 to day 365, after hospital discharge. The authors developed extended Cox regression models with a priori identified predictors. Sensitivity analyses used alternative cessation definitions (30 or 180 consecutive days). Results. Almost 60% of the patients received preoperative opioids: tramadol (7.5%), SA acute/intermittent (24.1%), SA chronic (17.5%), and LA (5.2%). For patients opioid-free preoperatively, median time-to-cessation of opioids postoperatively was 15 days. The SA acute/intermittent cohort (HR51.96; 95% CI51.92-2.00) had greater risk for prolonged time-to-cessation than those opioid-free (reference), but lower risk than those taking tramadol only, SA chronic (HR5 9.09; 95% CI5 8.33-9.09), or LA opioids (HR59.09; 95% CI58.33-10.00). Diagnoses of chronic pain, substance-use, or affective disorders were weaker positive predictors. Sensitivity analyses maintained findings. Conclusion. Greater preoperative levels of opioid use were associated with progressively longer time to- cessation postoperatively. [ABSTRACT FROM AUTHOR]