Estimated GFR Before and After Bariatric Surgery in CKD

Abstract

Background: Several reviews have recently detailed the beneficial effects of weight loss surgery for kidney function. However, these studies have a number of limitations, including small sample size, few done in chronic kidney disease (CKD) stages 3 and 4, and many not including the main bariatric surgery procedures used in the United States today. Study Design: This was an observational retrospective cohort study comparing propensity score–matched bariatric surgery patients and nonsurgery control patients who were referred for, but did not have, surgery. Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy were also compared using propensity matching. Setting & Participants: Patients (714 surgery patients; 714 controls) were from a large integrated health care system, a mean of 58 ± 8 (SD) years old, and mostly women (77%) and non-Hispanic whites (56%) and had diabetes mellitus (66%) and/or hypertension (91%). Predictor: Predictors at the time of surgery or referral to surgery were age, sex, race/ethnicity, weight, and presence of diabetes and/or hypertension. Outcomes: The primary outcome for this study was change in estimated glomerular filtration rate (eGFR) from serum creatinine level over a median 3-year follow-up period. Measurements: Serum creatinine was used to calculate eGFR using the CKD-EPI (CKD Epidemiology Collaboration) creatinine equation. Results: Surgery patients had 9.84 (95% CI, 8.05–11.62) mL/min/1.73 m2 greater eGFRs than controls at a median 3 years’ follow-up and RYGB patients had 6.60 (95% CI, 3.42–9.78) mL/min/1.73 m2 greater eGFRs than sleeve gastrectomy patients during the same period. Limitations: This study is limited by its nonrandomized observational study design, estimation of GFR, and large changes in muscle mass, which may affect serum creatinine level independent of changes in kidney function. Conclusions: Bariatric surgery, especially the RYGB procedure, results in significant improvements for up to 3 years in eGFRs for patients with CKD stages 3 and 4.

Laparoscopic Sleeve Gastrectomy Significantly Increases Serum Lipoprotein Lipase Level in Obese Patients

“…Bariatric surgery increased eGFR in obese patients with CKD [28]. In a previous study, although improvement of eGFR was greater by Roux-en-Y gastric bypass than LSG, eGFR increased from 48.5 to >60 mL/min/1.73 m 2 1 year after LSG [28]. Our study also showed significant improvement of eGFR 1 year after LSG.…”

“…Increased tumor necrosis factor-α (TNF-α) and monocyte chemotactic protein-1 (MCP-1) as well as ectopic lipid accumulation in the kidney were regarded as important mechanisms of ORG [26, 27]. Bariatric surgery increased eGFR in obese patients with CKD [28]. In a previous study, although improvement of eGFR was greater by Roux-en-Y gastric bypass than LSG, eGFR increased from 48.5 to >60 mL/min/1.73 m 2 1 year after LSG [28].…”

Is there improvement in renal function in patients undergoing bariatric surgery?

“…The literature suggests that the use of markers that suffer less interference due to loss of muscle mass, such as cystatin C, may be a better and more reliable alternative for estimating renal function in patients who lose weight sharply, especially when at the same time uses cystatin C and creatinine by CKD Epi, based on this evidence the analysis of the present study [27,34,37].…”

“…Studies have pointed the improvement of renal function after bariatric surgery, either with increased glomerular iltration rate in patients with chronic kidney disease [37], or reduction of hyper iltration in patients with no evidence of kidney disease [15,16,19]. However, in some studies the sample is too small and in others the biomarkers presents low sensitivity [17,18].…”

The Case for a Bariatric-Centered Approach to CKD Care

“…With regard to metabolic surgery, several recent observational studies report that it is associated with improvements in albuminuria, eGFR, and prognostic risk for CKD (5)(6)(7)(8). Two of these studies also reported slower progression to a composite end point of ESKD and stage 5 CKD or doubling of serum creatinine (5,7).…”