Comparison of eGFR formulas in determining chronic kidney disease stage in bariatric patients and the impact on perioperative outcomes.

Background: Chronic kidney disease (CKD) independently increases the risk of 30-day adverse outcomes following metabolic and bariatric surgery (MBS). However, no studies have evaluated the stage of CKD at which increased perioperative risk is manifested. Here, we correlate 30-day major morbidities after MBS with extent of renal disease based on CKD Stage.

Objectives: To determine the impact of CKD stage on perioperative outcomes after bariatric surgery.

Setting: Academic Hospital.

Methods: From the 2017 Metabolic and Bariatric Surgery Quality Improvement Program (MBSAQIP) database, we identified patients with CKD who underwent sleeve gastrectomy or laparoscopic gastric bypass surgery. Glomerular filtration rates (GFRs) were calculated and cohorts were generated based on CKD Stage. Complication rates and rates of morbidity and mortality were compared between stages, and strengths of correlation were calculated.

Results: GFR and CKD Stage were calculated for 150,283 patients. There was a significant increase in the risk of major morbidity at each progressive stage of CKD (P < .001 for all compared stages). There was a strong positive linear correlation between increasing CKD Stage and total morbidity (r = .983), including reoperation ( r = .784), readmission (r = .936), unplanned ICU transfer (r = .853), and aggregate complications such as pulmonary (r = .900), bleeding (r = .878), or progressive worsening of renal function (r = .845). In logistic regression, for every 10-point decrease in GFR, odds of total morbidity increased by 6%.

Conclusion: An increased risk of perioperative complications may be seen in early stages of CKD, and risk is compounded in more advanced stages. Bariatric surgical candidates should be counseled on their increased risk of surgical complications even with mild CKD, and the benefits of bariatric surgery should be carefully weighed against significantly increased risks of complications in severe CKD.