Effects of age, Gender, and hyperparathyroidism on lean body mass in hemodialysis patients

Hyperparathyroidism of hemodialysis patients is associated with osteo- dystrophy, impairment of cardiac function, of peripheral nerve conduction, of response to r-HuEPO and with decrease of lean body mass. Primary hyperparathyroidism of post-menopausal women is associated with increased fat mass (FM). The study investigated if gender varies relationship between i- PTH, and body composition, assessed by multifrequency bio-electrical impedance analysis (BIA), cardiac function, assessed by echocardiography, and anemia, in long-term hemodialysis patients. Seventy patients on long-term bicarbonate dialysis, 34 male and 36 post-menopausal female, were studied. i- PTH RIA, multifrequency BIA and Kt/V were assessed at three months intervals. i-PTH (345.88 ± 199.58 vs. 224.26 ± 161.62 pg/ml, p <0.01) and FM % (39.13 ± 10.42 vs. 30.95 ± 5.88, p<0.001) were both significantly higher in women vs men; BMI was not significantly different. In the total group of patients (r=0.572, p<0.001) and in women (r=0.68, p<0.001) a positive correlation was found between i-PTH and FM%, and reciprocally an inverse negative correlation with free fat mass (FFM) was observed. No significant relationship was observed in men. Decrease of blood pressure measurements and increase of left ventricular Ejection Fraction, in the comparison of beginning and end of three dialysis sessions, were significantly greater in women. Reduced FFM of women on dialysis could have also some relationship with a more close long- term adherence to dietary protein restriction. Hyperparathyroidism in chronic renal failure patients could share liability of bone structural abnormalities, cardiac function impairment, excitable tissue disease, and anemia. However, malnutrition, and its consequent relative decrease of lean mass, resulting from kidney disease and, possibly, from nutritional behavioral modifications, could be responsible of the multi-organ involvement of hyperparathyroidism in end-stage renal disease.