Effect of Bariatric Surgery on CKD Risk

Abstract

Obesity is linked to the development and progression of CKD, but whether bariatric surgery protects against CKD is poorly understood. We, therefore, examined whether bariatric surgery influences CKD risk. The study included 2144 adults who underwent bariatric surgery from March of 2006 to April of 2009 and participated in the Longitudinal Assessment of Bariatric Surgery-2 Study cohort. The primary outcome was CKD risk categories as assessed by the Kidney Disease Improving Global Outcomes (KDIGO) consortium criteria using a combination of eGFR and albuminuria. Patients were 79% women and 87% white, with a median age of 46 years old. Improvements were observed in CKD risk at 1 and 7 years after surgery in patients with moderate baseline CKD risk (63% and 53%, respectively), high baseline risk (78% and 56%, respectively), and very high baseline risk (59% and 23%, respectively). The proportion of patients whose CKD risk worsened was ≤10%; five patients developed ESRD. Sensitivity analyses using year 1 as baseline to minimize the effect of weight loss on serum creatinine and differing eGFR equations offered qualitatively similar results. Treatment with bariatric surgery associated with an improvement in CKD risk categories in a large proportion of patients for up to 7 years, especially in those with moderate and high baseline risk. These findings support consideration of CKD risk in evaluation for bariatric surgery and further study of bariatric surgery as a treatment for high-risk obese patients with CKD.

Keywords: CKD; bariatric surgery; chronic kidney disease; loss; obesity; prognosis; weight.

Figure 1.

Trend of overall improvement in CKD risk categories over 7-year period after bariatric surgery. Predicted proportions are obtained from generalized linear mixed models stratified by baseline prognostic CKD risk category and include visit and missing related baseline variables, age, race, and smoking status. The numbers above each bar represent the total numbers of participants with accessible data at each time point. The total number at baseline is shown on the far right of each row. BL, baseline.

Figure 2.

Trend of overall improvement in CKD risk categories after bariatric surgery using year 1 post-surgery as baseline. Predicted proportions are obtained from generalized linear mixed models stratified by baseline CKD risk category and include visit and missing related baseline variables, age, race, and smoking status. The numbers above each bar represent the total numbers of participants with accessible data at each time point. The total number at year 1 is shown on the far right of each row. Y1, year 1.