Pre-operative opioid use was an independent risk factor for severe complications as well as prolonged length of stay, readmission and reoperation after primary bariatric surgery, according to a study that included more than 56,000 patients. The findings were reported in the paper, 'Preoperative chronic opioid use and its impact on early complications in bariatric surgery: A Swedish nationwide cohort study of 56,183 patients', published in SOARD.
The study, by researchers from Uppsala University, Uppsala, Sweden, examined the impact of pre-operative opioid use on complications, length of stay, readmission and reoperation within 30 days in patients undergoing primary laparoscopic Roux-en-Y Gastric Bypass (LRYGB) and Sleeve Gastrectomy (LSG). Using data from the Scandinavian Obesity Surgery Register (SOReg) between 2007 and 2017, the study included 56,183 patients who had undergone primary LRYGB (n=49,615) or LSG (n=6,568), 17.5% (n=9,825) had at least one prescription of opioids prior to surgery, of which 4.3% (n=2,390) were defined as chronic opioid users. Patients were classified as chronic opioid user if they had at least one prescription of opioid analgesics within 30 to 90 days prior to surgery and at least another prescription 30-days prior to surgery.
Gender, age, BMI, year of surgery, type of procedure and the obesity-related comorbidities, depression, diabetes, dyspepsia, hypertension (dichotomised on medication or not) and sleep apnoea (use of CPAP), as well as previous venous thromboembolism (VTE) were obtained from SOReg.
Overall, 82.5% (n=46 358) of patients were opioid naïve, while 14.2% (n=7954), 1.7% (n=961) and 1.6% (n=909) had a low (<10 mg/day), middle (10 to 20 mg/day) and high (>20 mg/day) oral morphine equivalents (OME) exposure, respectively. The most prescribed opioid was tramadol (45.6% of all prescriptions), followed by codeine (30.5%), oxycodone (14.5%), morphine (2.7%) and buprenorphine (2.3%).
The overall 30-day complication rate was 6.9% (n=3,868), of which 2.8% (n=1547) had a severe complication (CD≥3b). A severe complication occurred more frequently among all chronic opioid users, 4.7% (n=112) vs. 2.7% (n=1,435), p<0.001 (univariate analysis). After multivariate regression analysis, chronic opioid use was still associated with an increased risk of severe complication (p<0.001) with an adjusted 30-day complication rate of 4.4%. In a sub analysis of specific complications, chronic opioid use was associated with an increased risk of leakage/abscess, bleeding, bowel obstruction and pulmonary complications.
Chronic opioid users had a slightly longer LOS compared to the other patients (p<0.001, univariate analysis). The relative risk of increased LOS remained significantly higher for chronic opioid users (p<0.001, after multivariate regression analysis). Opioid users had a significantly higher risk for longer hospital stay, except for those with low OME exposure, compared to the opioid naïve group.
The overall 30 days readmission rate was 7.0% (n=3,911) and a higher rate was observed among chronic opioid users 11.3% (n=269) vs. 6.8% (n=3642), p<0.001 (univariate analysis). After multivariate regression analysis chronic opioid use was still associated with an increased risk of readmission within 30 days (<0.001).
Overall, 2.6% (n=1,480) had a reoperation related to a complication within 30 days, which was more common among chronic opioid users, 4.9% (n=117) vs. 2.5% (n=1363), p<0.001 (univariate analysis). Chronic opioid use was still associated with an increased risk for reoperation within 30 days (p<0.001, after multivariate regression analysis).
Chronic opioid users in the LRYGB-group had an increased risk of severe complication (p<0.001), longer LOS (p<0.001), increased risk of readmission (p<0.001) and reoperation (p<0.001) within 30 days. However, no association was observed in the LSG-group.
“Pre-operative opioid use is common among patients undergoing bariatric surgery and represents an independent risk factor for severe complications as well as prolonged length of stay, readmission and reoperation after primary LRYGB and LSG,” the authors concluded. “Furthermore, higher OME exposure was associated with stepwise higher risks. Patients using opioid analgesics before bariatric surgery require special attention during the perioperative phase.”
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