Impaired muscle strength is associated with fractures in hemodialysis patients
Fractures are extremely common among hemodialysis (HD) patients. To assess if bone mineral density (BMD) and/or tests of muscle strength were associated with fractures, we studied 37 men and 15 women, 50 years and older, on HD for at least 1 year. We excluded subjects with prior renal transplants and women taking hormone replacement therapy. We inquired about low-trauma fractures since starting dialysis. Subjects underwent BMD testing with a Lunar DPX-L densitometer. Tests of muscle strength included: timed up and go (TUG), 6-min walk, functional reach, and grip strength. Lateral and thoracic radiographs of the spine were obtained and reviewed for prevalent vertebral fractures. We used logistic regression to examine associations between fracture (prevalent vertebral, self-reported low trauma since starting dialysis and/or both) and BMD, and fracture and muscle-strength tests. Analyses were adjusted for age, weight, and gender. Mean age was 66±9.0 years, mean weight was 72.9±15.2 kg, and most (35 of 52) participants were Caucasian. Average duration of dialysis was 40.2 (interquartile range: 24–61.2) months. The most common cause of renal failure was diabetes (16 subjects). There were no differences by gender or fracture. Of the 52 subjects, 27 had either a vertebral fracture or low trauma fracture. There was no association between fractures, hip or spine BMD, or grip strength. In contrast, greater functional reach [odds ratio (OR) per standard deviation (SD) increase: 0.29; 95% CI: 0.13–0.69), quicker TUG (OR per SD decrease: 0.14; 95% CI: 0.11–0.23), and a greater distance walked in 6 min (OR per SD increase: 0.10; 95% CI: 0.03–0.36) were all associated with a reduced risk of fracture. Impaired neuromuscular function is associated with fracture in hemodialysis patients.