BACKGROUND

Obesity is a risk factor for chronic kidney disease (CKD) and a relative contraindication for renal transplantation. Bariatric surgery (BS) is an option to address this issue but we hypothesize that severe CKD is associated with a loss of efficacy of BS which could justify recommending it at an earlier stage of the CKD.

METHODS

A retrospective study (n = 101 patients) to test primarily for differences in weight loss at 6 and 12 months according to estimated glomerular filtration rate categories (eGFR < 30 including patients on dialysis, 30-60, 60-90, and ≥ 90 ml/min/1.73 m) was performed with multivariate analysis adjusted for sex, age, BMI, surgical procedure, and diabetes. We used a second method to confirm our hypothesis comparing weight loss in patients with stage 4-5 CKD (eGFR < 30 ml/min/1.73 m, n = 17), and matched controls with eGFR ≥ 90 ml/min/1.73 m.

RESULTS

In the first comparison, the multivariate analysis showed a significant positive association between eGFR and weight loss. However, after exclusion of the subgroup of patients with eGFR < 30 ml/min/1.73 m, the difference between groups was no more significant. In addition, percent total weight loss (%TWL) was significantly lower in patients with severe CKD compared to controls: - 15% vs - 23% at 6 months (p < 0.01); - 17% vs - 27% at 12 months (p < 0.01). The percent excess weight loss at 1 year reached 47% in patients with stage 4-5 CKD and 68% in controls subjects (p < 0.01). Surgery was a success at 12 months (weight loss > 50% of excess weight) in 38% of advanced CKD and 88% of controls (p < 0.01).

CONCLUSION

The efficacy of BS was reduced in patients with advanced CKD. These results support early BS in patients with early-to-moderate CKD.