A Retrospective Study of Acute Postoperative Pain After Cesarean Delivery in Patients With Opioid Use Disorder Treated With Opioid Agonist Pharmacotherapy.

Abstract

We aimed to quantify the effect of opioid agonist pharmacotherapy on pain management after cesarean delivery, compared with patients not on these medications. Patients undergoing cesarean delivery at our institution between January 2016 and December 2018 were stratified by peripartum use of opioid agonist pharmacotherapy versus no agonist therapy. We compared 24-hour postoperative opioid consumption not including buprenorphine and methadone, in milligram morphine equivalents (MME) (primary outcome), highest pain score on a 0 to 10 numerical rating scale in the first 24 postoperative hours, and postoperative length of stay in hours (secondary outcomes) between groups. These outcomes were also compared after covariate adjustment using logistic regression. We identified 123 patients on opioid agonist pharmacotherapy - in the form of buprenorphine or methadone and 2856 patients not on these medications. The groups differed in demographic characteristics, including age, smoking, and marital status. Opioid consumption during the first 24 postoperative hours (median [interquartile range]) was 99 [75,120] MME for patients on agonist therapy and 30 [0, 64] MME among parturients not taking these medications ( P < 0.001). Highest pain scores during this time were also higher for patients on opioid agonist pharmacotherapy (mean [standard deviation]: 8.2 [1.6] vs 5.5 [2.2], P < 0.001 for the no agonist group). Postoperative length of stay was 73 [68, 77] hours for patients on agonist pharmacotherapy, and 71 [62, 76] hours for parturients taking no agonist ( P < 0.001). All differences remained significant after covariate adjustment. Parturients on opioid agonist pharmacotherapy have markedly increased opioid utilization and pain severity after cesarean delivery.