Association between higher BMI and postoperative pain and opioid consumption in pediatric inpatients - A retrospective cohort study.

BACKGROUND:Childhood and adolescent obesity increased in recent decades, and caregivers face an increasing number of obese pediatric surgical patients. Some clinical and pharmacogenetic data suggest that obese patients have altered pain sensitivity and analgesic requirements. OBJECTIVE:To test the primary hypothesis that increased BMI in pediatric patients is associated with increased pain during the initial 48 postoperative hours. Secondarily, we tested whether BMI is associated with increased opioid consumption during the same period. DESIGN:Retrospective single-center cohort study. SETTING:Pediatric surgical wards in a tertiary medical center. PATIENTS:A total of 808 opioid naïve patients aged 8 to 18 years having elective non-cardiac surgery with hospital stay of at least 48 h in the Cleveland Clinic between 2010 and 2015. INTERVENTIONS:None. MEASUREMENTS:Using U.S. Centers for Disease Control definitions for childhood weight classifications, we retrospectively evaluated the association between body mass index (BMI) percentile and time-weighted average pain scores and opioid consumption. We used multivariable linear regression to test for an association with postoperative pain scores, and multivariable gamma regression to test for an association with postoperative opioid consumption (in mg morphine equivalents Kg-1). RESULTS:BMI was not associated with postoperative pain after general, orthopedic, or neuro-spinal surgeries. Pain increased by 0.07 [98.75% CI: (0.01, 0.13), Padj < 0.05] points per 5 percentile increase in BMI after neuro-cranial surgery. Higher BMI was associated with a decrease in postoperative opioid consumption (mean change [95% CI] -2.12% [-3.12%, -1.10%] in morphine equivalents Kg-1 per 5 percentile increase in BMI, P < 0.001). CONCLUSION:We found no clinically important increase in pain scores or opioid consumption in association with higher BMI in patients 8 to 18 years of age recovering from elective non-cardiac surgery.