Normal weight and waist obesity indicated by increased total body fat associated with all-cause mortality in stage 3-5 chronic kidney disease

Patients with chronic kidney disease (CKD) demonstrate a survival benefit with a high body mass index (BMI); this is the obesity paradox. Central obesity has a higher prognostic value than BMI, even in those with normal weight. Whether total body fat percentage (TBF%) provides more information than BMI and waist circumference (WC) remains unknown. We included 3,262 Asian patients with stage 3-5 CKD and divided these patients by TBF% and waist-to-height ratio (WHtR) quartiles (Q1-Q4). TBF% was associated with BMI, WC, nutritional markers, and C-reactive protein. In all patients, BMI but not TBF% or WHtR demonstrated a survival paradox. In patients with BMI <25 kg/m(2), but not in those with BMI >= 25 kg/m(2), TBF% Q4 and WHtR Q4 were associated with all-cause mortality, with hazard ratios [HRs; 95% confidence intervals (CIs)] of 2.35 (1.31-4.22) and 1.38 (1.06-1.80), respectively. The HRs of TBF% Q4 for all-cause mortality were 2.90 (1.50-5.58) in patients with a normal WC and 3.81 (1.93-7.50) in patients with normal weight and normal WC (All P for interaction < 0.05). In conclusion, TBF% can predict all-cause mortality in patients with advanced CKD and a normal weight, normal WC, or both.

Automated summary

The obesity paradox exists in patients with chronic kidney disease, with high body mass index (BMI) associated with improved survival. Central obesity has a stronger prognostic value than BMI. Total body fat percentage (TBF%) may provide more information than BMI and waist circumference (WC). TBF% can predict all-cause mortality in patients with advanced CKD and normal weight, normal WC, or both.