Long-term opioid use after bariatric surgery

Abstract

Background: Opioid analgesics are often prescribed to manage pain after bariatric surgery, which may develop into chronic prescription opioid use (CPOU) in opioid-naïve patients. Bariatric surgery may affect opioid use in those with or without presurgical CPOU.

Objective: To compare CPOU persistence and incidence in a large multisite cohort of veterans undergoing bariatric surgery (open Roux-en-Y gastric bypass, laparoscopic RYGB, or laparoscopic sleeve gastrectomy) and matched nonsurgical controls.

Setting: Veterans Administration hospitals.

Methods: In a retrospective cohort study, we matched 1117 surgical patients with baseline CPOU to 9531 nonsurgical controls, and 2822 surgical patients without CPOU at baseline to 26,392 nonsurgical controls using sequential stratification. CPOU persistence in veterans with baseline CPOU was estimated using generalized estimating equations by procedure type. CPOU incidence in veterans without baseline CPOU was estimated in Cox regression models by procedure type because postoperative pain, complications, and absorption may differ by procedure.

Results: In veterans with baseline CPOU, postsurgical CPOU declined over time for each surgical procedure; these trends did not differ between surgical patients and nonsurgical controls. In veterans without baseline CPOU, compared with nonsurgical controls, bariatric patients had higher CPOU incidence within 5 years after open Roux-en-Y gastric bypass (hazard ratio = 1.19; 95% confidence interval: 1.06-1.34) or laparoscopic open Roux-en-Y gastric bypass (hazard ratio = 1.22, 95% confidence interval: 1.06-1.41). Veterans undergoing laparoscopic sleeve gastrectomy had higher CPOU incidence 1 to 5 years after surgery (hazard ratio = 1.28; 95% confidence interval: 1.05-1.56) than nonsurgical controls.

Conclusions: Bariatric surgery was associated with greater risk of CPOU incidence in patients without baseline CPOU but was not associated with greater CPOU persistence.

Keywords: Bariatric; Gastric bypass; Matching; Medication; Obesity; Opioid; Sleeve gastrectomy; Surgery; Veterans.

Figure 1.

Trends in Bariatric Surgical Volume for All Patients and Model-estimated CPOU Persistence: Proportion of Patients with Post-operative CPOU up to 5 Years in Matched Bariatric Surgical Patients and Non-Surgical Patients with Chronic Prescription Opioid Use at Baseline, by Bariatric Procedure Note: Figures on the left-hand side showing trends in surgical volume include patients with and without CPOU at baseline.

Figure 2.

Unadjusted CPOU Incidence: Kaplan-Meier Estimated Cumulative Incidence of Post-operative CPOU up to 5 Years in Matched Bariatric Surgical Patients and Non-Surgical Patients without Chronic Prescription Opioid Use at Baseline, by Bariatric Procedure

Figure 3.

Adjusted CPOU Incidence: Association and 95% Confidence Intervals of Bariatric Surgery and CPOU Incidence up to 5 Years after Surgery in Patients without Chronic Prescription Opioid Use at Baseline Note: The proportional hazards assumption was not met for patients receiving LSG, hazard ratios were estimated separately for the first year of following and the remaining years 1-5. Proportional hazards assumption was met for patients undergoing RYGB procedures, so hazard ratios were estimated for the entire 5-year period for these cohorts. Hazard ratios and 95% confidence intervals are from Cox models in matched surgical patients and non-surgical controls without chronic prescription opioid use at baseline. HR=hazard ratio; RYGB=Roux-en-Y gastric bypass; LSG=laparoscopic sleeve gastrectomy.