O1004: Opioid and Methadone Prescribing for Infants with Surgical Congenital Heart Disease

Background: Opioids are commonly prescribed postoperatively for infants undergoing surgery for congenital heart disease (CHD). Some infants receive non-methadone opioids for prolonged periods and require subsequent methadone treatment for physiologic opioid dependence or to wean from opioid therapy. The Risk Adjustment for Congenital Heart Surgery-2 (RACHS-2) criteria is used to categorize patients by risk of operative mortality (1 = lowest risk, 5 = highest risk). We hypothesized that infants with higher RACHS-2 score would have higher risk of postoperative methadone treatment.

Methods: A retrospective cohort of infants < 1y undergoing surgery for CHD from January 2016-December 2022 at 48 children’s hospitals from the Pediatric Health Information System (PHIS) was performed. Infants were categorized by RACHS-2 criteria. A multivariable hierarchical logistic regression model evaluated the association between cumulative number of postoperative non-methadone opioid days and subsequent methadone treatment. An interaction term identified differences in the probability of methadone treatment by postoperative opioid days between RACHS-2 categories. For infants receiving methadone, postoperative length of stay, ventilator days, and total parenteral nutrition (TPN) days were compared to infants not receiving methadone using univariate logistic regression.

Results: Overall, 34,127 infants undergoing CHD surgery were identified, 15,254 infants were female (44.7%), 21,441 White (62.8%), 6,386 Hispanic/Latino (18.7%), and 6,408 preterm (18.8%). The distribution across RACHS-2 score categories in our cohort for scores 1-5 were 25.0%, 35.6%, 14.4%, 16.7%, and 8.3%. Increasing RACHS-2 score was associated with increasing cumulative number of postoperative non-methadone opioid days (p < 0.001) (Table). After adjusting for demographic and clinical factors, we found a significant interaction between RACHS-2 score and cumulative postoperative opioid treatment days (Figure). For infants receiving non-methadone opioids for less than 17 days, increasing RACHS-2 score was associated with increasing predictive probability of postoperative methadone treatment. After 17 days, patients with a RACHS-2 designation of 1 have the highest likelihood of postoperative methadone treatment, but also represented a minority outlier within the group of all infants with a RACHS-2 score of 1. Methadone treatment was associated with 10.4 more postoperative days (95% CI, 9.19-11.63, p< 0.001), 13.9 more ventilator days (95% CI, 13.3-14.6, p< 0.001), and 17.3 more TPN days (95% CI,16.1-18.7, p< 0.001).

Conclusion: In this multi-institutional retrospective cohort study of infants with surgical CHD, increasing RACHS-2 score was associated with increasing likelihood of methadone treatment in the first 17 days after surgery. Methadone treatment was associated with increased postoperative length of stay, ventilator days, and TPN use. For infants who receive longer courses of postoperative non-methadone opioids, the probability of methadone treatment changes and is more likely for those with lower RACHS-2 scores, although these patients represent minority outliers. These findings highlight subpopulations of CHD infants who could be identified as optimal candidates for opioid stewardship initiatives.