Characterization of Body Composition and Fat Mass Distribution 1 Year After Kidney Transplantation.

Purpose: In some recipients, significant weight gain occurs after kidney transplantation. Weight gain is associated with poor outcomes, particularly increased cardiovascular risk. In this study, we characterized changes in body mass index and body fat mass and compared them based on gender and race.

Methods: Fifty-two kidney transplant recipients (aged ≥18 years old, 50% men, 58% African American) were enrolled into a prospective study. Body mass index and body fat mass were measured at baseline and 12 months posttransplant. Body fat mass was determined by dual-energy X-ray absorptiometry.

Results: The mean increase in body weight was 3.7kg at 12 months; 36.5% (n=19) gained at least 10% of their baseline body weight. Body mass index, percentage of total body fat, and trunk fat were significantly increased. In subgroups, women and African American showed significant increases in body mass index and body fat measures. More participants were classified as obese based on total body fat compared to body mass index. Calories from fat were significantly increased at 12 months and associated with increased body mass index, total body fat, and trunk fat. Days of physical activity were significantly increased.

Conclusion: Both body mass index and total body fat mass were significantly increased at 12 months following kidney transplantation, especially for women and African Americans. Importantly, more participants were classified as obese based on total body fat compared to body mass index. Relevant nutrition and physical intervention should be provided, and both body mass index and body fat mass should be evaluated when monitoring weight gain.