The Impact of CKD on Perioperative Risk and Mortality after Bariatric Surgery.

Background: Twenty percent of patients with CKD in the United States have a body mass index (BMI) ≥35 kg/m. Bariatric surgery reduces progression of CKD to ESKD, but the risk of perioperative complications remains a concern.

Methods: The 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 on the basis of 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% were women, and 71.2% were White. Mean BMI was 45.7±7.6 kg/m. Compared with patients with an eGFR≥90 ml/min per 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 to 2.67; <0.001). Similarly, length of hospital stay beyond 2 days was 2.05-fold (95% CI, 1.64 to 2.56; <0.001) higher and risk of deep incisional SSI was 6.92-fold (95% CI, 1.62 to 29.52; =0.009) higher for those with stage 5 CKD/ESKD. Risk of early postoperative mortality increased with declining preoperative eGFR, such that patients with stage 3b CKD were 3.27 (95% CI, 1.82 to 5.89; <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 stage 3b CKD. Furthermore, absolute mortality rates were <0.5% in those with stages 4 and 5 CKD, and these advanced CKD stages were not independently associated with an increased risk of early postoperative mortality.

Conclusions: 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.