Objective: To test the hypothesis that patients who continued buprenorphine postoperatively experience less severe pain and require a smaller dose of opioids than those who discontinued buprenorphine.
Materials and methods: This is a retrospective cohort study of surgical patients who were on buprenorphine preoperatively. Using our previous study's data as pilot data, we selected the covariates to be included in 2 regression models with postoperative time-weighted average pain score and opioid dose requirements in morphine milligram equivalents during 48 hours after surgery as the outcomes. Both contained preoperative daily buprenorphine dose, whether buprenorphine was continued postoperatively, and the preoperative daily dose-by-postoperative continuation interaction as predictors. Precision variables were identified by exhaustive search of perioperative parameters with the exposure variables (preoperative daily dose, postoperative continuation, and their interaction) included in the regression model. The model selected by using the pilot data was estimated again using the new data extracted for this study to make inference about the effect of the 2 exposures (postoperative buprenorphine continuation and preoperative daily buprenorphine dose) and their interaction on the outcomes.
Results: Continuing buprenorphine was associated with a 1.3-point lower time-weighted average pain score than discontinuing (95% confidence interval, 0.39-2.21; P=0.005) but was not associated with a difference in opioid dose requirements (P=0.48).
Discussion: Continuing buprenorphine was associated with lower postoperative pain levels than discontinuing. Our results were primarily driven by patients on lower buprenorphine dose as only 22% of patients were on daily doses of 24 mg or above.
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