Post-cesarean opioid consumption in patients on maintenance medication for opioid use disorder undergoing cesarean delivery with neuraxial anesthesia: a single-center retrospective propensity-matched cohort study (2016-2020).

BACKGROUND

Scheduled multimodal non-opioid analgesics after cesarean delivery are effective in reducing opioid consumption. However, there is limited information regarding the effectiveness of this practice for reducing opioid consumption in patients on opioid agonists (methadone or buprenorphine) for an opioid use disorder. We hypothesized that standardized neuraxial anesthesia with neuraxial morphine and multimodal non-opioid analgesics would result in similar postoperative opioid consumption between patients on opioid agonist therapy and opioid-naïve controls.

METHODS

This was a single-center retrospective cohort study on patients undergoing cesarean delivery with intrathecal morphine (median 200 μg) between January 2016 and December 2020. We compared 48-hour postoperative opioid consumption (milligram morphine equivalents; MME) between patients on opioid agonist therapy and matched controls (median MME [25th-75th percentile]). Secondary outcomes included pain scores (numeric rating; 0-10) and postoperative length of stay. The MME consumption was adjusted for covariates (e.g. current tobacco use, mental health diagnosis - anxiety, depression, bipolar, schizophrenia) using logistic regression.

RESULTS

We identified 125 patients on opioid agonist therapy (buprenorphine n = 30, methadone n = 95), who were propensity-matched 1:1 with opioid-naive controls. Patients on opioid agonists had significantly higher 48-hour opioid consumption (82.5 [45.0-124.5] vs. 25.0 [15.0-46.0] MME; P < 0.001), higher average pain scores (4.6 [3.5-5.8] vs. 3.4 [2.1-4.7]; P < 0.001), and higher peak pain scores (7.0 [5.0-9.0] vs. 4.8 [3.7-6.6]; P < 0.001). Mental health diagnoses were associated with increased opioid consumption, and the differences between groups remained significant after covariate adjustments. The length of stay was similar between the two groups (2.0 [2.0-3.0] days; P = 0.44).

CONCLUSIONS

Pregnant women maintained on their pre-delivery dose of opioid agonists after cesarean delivery had opioid consumption and pain scores after undergoing cesarean delivery under neuraxial anesthesia with neuraxial morphine despite optimizing multimodal non-opioid analgesic medications than matched controls. Within both groups, the diagnosis of a mental health diagnosis was highly associated with increased MME consumption.