The impact of chronic kidney disease on perioperative risk and mortality after bariatric surgery

Abstract

Background: 20% of patients with chronic kidney disease (CKD) in the United States have a body-mass index (BMI) ≥35 kg/m2. Bariatric surgery reduces progression of CKD to end-stage kidney disease (ESKD), but the risk of perioperative complications remains a concern. Methods: 24-month data spanning 2017-2018 were obtained from the Metabolic and Bariatric Surgery Quality Improvement Program (MBSAQIP) database and analyzed. Surgical complications were assessed based on the length of hospital stay, mortality, reoperation, readmission, surgical site infection (SSI), and worsening of kidney function during the first 30 days after surgery. Results: The 277,948 patients who had primary bariatric procedures were 44±11.9 (mean±SD) years old, 79.6% female, and 71.2% Caucasian. Mean BMI was 45.7±7.6 kg/m2. Compared with patients with an eGFR ≥90 mL/min/BSA, those with stage 5 CKD/ESKD were 1.91 times more likely to be readmitted within 30 days of a bariatric procedure (95% CI, 1.37-2.67; p<0.001). Similarly, length of hospital stay beyond 2 days was 2.05-fold (95% CI, 1.64-2.56; p<0.001) higher and risk of deep incisional surgical site infection was 6.92-fold (95% CI, 1.62-29.52; p=0.009) higher for those with stage 5 CKD/ESKD. Risk of early postoperative mortality increased with declining preoperative eGFR, such that patients with CKD stage 3b were 3.27 (95% CI, 1.82-5.89; p<0.001) times more likely to die compared with those with normal kidney function. However, absolute mortality rates remained relatively low at 0.53% in those with CKD stage 3b. Furthermore, absolute mortality rates were less than 0.5% in those with CKD stages 4 and 5, and these advanced CKD stages were not independently associated with an increased risk of early postoperative mortality. Conclusion: Increased severity of kidney disease was associated with increased complications after bariatric surgery. However, even for the population with advanced CKD, the absolute rates of postoperative complications were low. The mounting evidence for bariatric surgery as a renoprotective intervention in people with and without established kidney disease suggests that bariatric surgery should be considered a safe and effective option for patients with CKD.