C-reactive protein is a significant predictor of decrease in fat mass in hemodialysis patients

Malnutrition and inflammation are common in hemodialysis patients, and are usually closely associated. We examined annual body fat mass changes, a possible nutritional parameter, in maintenance hemodialysis patients, and investigated the factors affecting such changes. Body fat mass of 454 hemodialysis patients (61 ± 11 years, 269 males and 185 females) was measured twice by dual energy X-ray absorptiometry (DEXA), with a 12-month interval between measurements. In a total of 65 patients with hemodialysis duration of less than 1 year at the first measurement, fat mass at the second measurement had increased significantly over the course of a year (P < 0.0001). In contrast, in a total of 389 patients with hemodialysis duration of more than 1 year at the first measurement, fat mass at the second measurement significantly decreased (P < 0.005). In the 389 patients, significant negative correlations were seen between fat mass changes and CRP (r = -0.165, P < 0.005). In a multiple regression analysis, CRP was a significant factor (β = -0.163, P < 0.005) affecting fat mass changes, independent of other confounding clinical factors (R2 = 0.127, P < 0.001). These results show that body fat mass of long-term hemodialysis patients decreases after an initial increase in the first to second years of hemodialysis. In hemodialysis patients, fat mass change appears to be a parameter indicative of nutritional changes. Chronic inflammation, represented by higher CRP levels, is a significant factor affecting decrease in fat mass, and is related to poorer nutritional status.