How obesity and metabolic syndrome affect cardiovascular events, progression to kidney failure and all-cause mortality in chronic kidney disease
Shin Yeong Kang, Yu Ho Lee, Su Jin Jeong, Jin Sug Kim, Kyung Hwan Jeong, Hyeon Seok Hwang
Abstract
BACKGROUND: 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. METHODS: 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 ≥25 kg/m2. MetS was defined as the presence of three or more metabolic risks. RESULTS: 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). CONCLUSIONS: 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.