Predictors of postoperative eGFR change and resolution of hyperfiltration in obese patients following bariatric surgery

Background: Bariatric surgery (BS) can improve glomerular hyperfiltration (GHPF). Very few studies identified associative factors with glomerular filtration rate and resolution from GHPF after BS.

Objectives: To investigate the predictors of estimated GFR (eGFR) changes and resolution from GHPF after BS.

Setting: University hospital, Republic of Korea.

Methods: We enrolled patients who underwent BS for obesity from January 2008 to December 2014 and had more than a year of follow-up. GHPF was defined as an eGFR above 95th percentile values for age- and sex-matched cohorts extracted from the Korea National Health and Nutrition Examination Survey Database. Patients with baseline eGFR less than 60 mL/min/1.73 m² were excluded.

Results: A total of 138 patients (age interquartile range [IQR] 28-43; 21 men, 117 women) were analyzed. The median follow-up period was 36 months (IQR 25-45 mo). One hundred twenty patients (87%) were defined as having GHPF and 75 (54%) resolved after surgery. Multivariate analysis found that sex, preoperative body mass index (BMI), and age were predictive of postoperative eGFR. In patients with preoperative GHPF, female and lower BMI groups had significantly higher resolution rates (P = .012 for sex, P = .016 for BMI). Younger age was related with early resolution after BS.

Conclusions: Younger patients had a faster eGFR decline after BS. Predictive factors for resolution of GHPF after BS include female sex and lower BMI.