Cystatin C-estimated GFR correlates with endothelial function improvements following bariatric surgery

Area of Science:

• Metabolic Surgery
• Nephrology
• Cardiovascular Science

Background:

• Obesity is a major risk factor for chronic kidney disease (CKD) and cardiovascular disease (CVD).
• Endothelial dysfunction is a key mechanism linking obesity to CKD and CVD.
• Assessing the interplay between renal and vascular health is crucial in severe obesity.

Purpose of the Study:

• To investigate the relationship between endothelial function (flow-mediated dilation, FMD) and kidney function (cystatin C-based estimated glomerular filtration rate, eGFRcys) in severe obesity.
• To evaluate the impact of bariatric surgery on these parameters.
• To compare the utility of cystatin C-based vs. creatinine-based eGFR in reflecting vascular health changes.

Main Methods:

• Sixty-five individuals with BMI >35 kg/m² underwent assessment before and 1 year after bariatric surgery.
• Vascular health was assessed using FMD, pulse wave velocity (PWV), and renal resistive index.
• Kidney function was measured using both creatinine-based (eGFRcr) and cystatin C-based (eGFRcys) equations.

Main Results:

• Bariatric surgery significantly improved BMI, FMD, and eGFRcys.
• Pre-surgery, eGFRcys positively correlated with FMD and inversely with PWV; eGFRcr showed weaker associations.
• Post-surgery, eGFRcys increases correlated with FMD improvements, independent of BMI or blood pressure. eGFRcr did not show significant associations with FMD changes.

Conclusions:

• Bariatric surgery effectively enhances both renal and vascular health in individuals with severe obesity.
• Cystatin C-based eGFR demonstrates a stronger correlation with improvements in endothelial function compared to creatinine-based eGFR.
• Cystatin C serves as a valuable integrative marker for assessing combined renal and vascular risk in obesity management.