How obesity and metabolic syndrome affect cardiovascular events, progression to kidney failure and all-cause mortality in chronic kidney disease.

Abstract

Obesity and metabolic syndrome (MetS) are prevalent among chronic kidney disease (CKD) patients. However, it is unclear whether obesity without MetS is associated with a higher risk of adverse clinical outcomes in CKD patients. We searched the National Health Insurance Service database of Korea for patients who underwent national health screenings in 2009-11 and identified 59 725 CKD patients. Obesity was defined as a body mass index ≥25kg/m2. MetS was defined as the presence of three or more metabolic risks. The cumulative event rate of cardiovascular (CV) events, progression to end-stage kidney disease (ESKD) and all-cause mortality was the lowest among obese patients without MetS (all P<.001). In multivariable analysis, obese (versus non-obese) patients without MetS were not at increased risks of CV events [adjusted hazard ratio (HR) 1.02 (95% confidence interval 0.94-1.11)] or progression to ESKD [0.92 (0.77-1.09)]. Their risk of all-cause mortality was significantly decreased [0.82 (0.75-0.90)]. These findings were consistently observed in overweight, obese and morbidly obese patients without MetS. Moreover, despite a linear increase in HR for each additional metabolic abnormality in both obese and non-obese patients, the slope of HR increase for CV events was significantly slower in obese patients (P for interaction=.038). Obesity without MetS did not increase the risk of CV complications or progression to ESKD. The healthy effect of obesity on all-cause mortality risk and its weakening effect on the association between metabolic hazards and CV risk should be considered in CKD patients.