Normal-weight obesity (NWO), defined by a normal body mass index (BMI) and high body fat percentage, has been shown to be associated with cardiometabolic dysfunction and an increased risk of cardiovascular disease and mortality in the general population. However, little is known about the clinical implications of NWO among patients with chronic kidney disease (CKD).
Objective
The aim of this study was to assess the characteristics and outcomes of nondiabetic CKD patients with NWO.
Design
A total of 178 nondiabetic patients with stages 3–5 CKD were prospectively followed for a median of 4.9 y. The patients were classified into 3 different adiposity phenotypes: nonobese [BMI (in kg/m2) <25 and fat mass percentage (FM%) ≤25% for men or ≤35% for women], NWO (BMI <25 and FM% >25% for men or >35% for women), and preobese-obese (BMI ≥25). FM% was determined using the Body Composition Monitor, a multifrequency bioimpedance spectroscopy device. The outcome was a composite of cardiovascular events or all-cause mortality.
Results
The prevalence of NWO was 28.1% among nondiabetic CKD patients with a normal BMI. NWO patients were older, had lower lean body mass, and had higher plasma interleukin-6 concentrations than nonobese patients. However, homeostatic model assessment for insulin resistance levels did not differ between the 2 groups. NWO patients showed a significant 3-fold higher risk of the composite outcome (HR 2.96, 95% CI: 1.13, 7.77; P < 0.05) than did nonobese patients in the fully adjusted model. Preobese-obese patients were not at increased risk compared to nonobese patients.
Conclusions
NWO was associated with the worst prognosis among the 3 different adiposity phenotypes in nondiabetic CKD patients. Our findings suggest the importance of using direct measures of adiposity for risk assessment in CKD patients who are normal-weight.
Supported by grants from Research Projects MOST 103-2314-B-005-MY2 and MOST 105-2314-B-014-MY3, the Ministry of Science and Technology, ROC, and the Research Projects TCRD-TPE-106-RT-5 and TCRD-TPE-107-18, Taipei Tzu Chi Hospital, Taiwan.
The sponsors and the funders of the study had no role in the data collection and analysis, interpretation of this work, or the decision to submit this work for publication.
