Total Body Mass Is Better Than Body Mass Index As a Prognostic Parameter for Bone Mineral Density in Dialyzed Patients

摘要

Assuming that nutrition status also influences bone mineral density (BMD) in dialyzed patients, we compared BMD in two groups of dialyzed patients: those with a body mass index (BMI) above 25 kg/m~2 [group I: n = 20; 11 women; 19 on peritoneal dialysis (PD), 1 on hemodialysis (HD); age: 60.9 +-13.6 years; time on dialysis: 19.3 months (range: 6.5 - 45.7 months)], and those with a BMI below 25 kg/m~2 [group II: n = 10; 7 women; 7 on PD, 3 on HD; age: 46.6 +- 21.8 years; time on dialysis: 21.3 months (range: 6.3 - 59.6 months)]. Anthropometric indices of nutrition status and body composition by bioimpedance analysis were checked in all patients. We measured BMD in the femoral neck (FN) and lumbar spine by dual-energy X-ray absorptiometry. Laboratory parameters of nutrition, inflammatory status, and Ca-P balance were simultaneously measured. Influence of age and sex on BMD was taken into consideration. The patients in group I were significantly older than the patients in group II (p = 0.035), but they had significantly higher BMD parameters. After regression analysis, which included age, sex, hip and waist circumferences, total body mass, lean and fat body mass, and BMI in all dialyzed patients, age (beta = -0.558, DELTAR~2 = 0.131, p = 0.003) and total body mass (beta = 0.408, DELTAR~2 = 0.131, p = 0.024) were the only independent variables that predicted FN BMD, age being the stronger predictor. In dialysis patients, BMI is associated with BMD, but the only important parameter of body composition for predicting FN BMD in this group is total body mass.