Bone pain in dialysis patients is not associated with bone mineral density but with serum concentration of small uremic toxins.

PURPOSE Abnormalities in bone mineral density (BMD) are frequent disorder in dialysis patients. In our study we checked if such clinical symptom as bone pain may be associated with BMD. PATIENTS AND METHODS The study was performed in 30 dialysis patients. They were divided according to declared or not declared bone pain in any localization. The group with bone pain (n=10) included 7 women and 3 men, age 57.4 +/- 16.2 years, dialysis vintage 19.3, 6.5-45.5 months. The group without bone pain (n=20) consisted of 11 women and 9 men, age 55.5 +/- 18.9 years, dialysis vintage 20.5, 6.3-59.6 months. BMD was assessed by dual-energy x-ray absorptiometry in femoral neck (N) and lumbar spine from the second to the fourth lumbar vertebra (L2-L4). Routine clinical and laboratory parameters were evaluated and compared in both groups. RESULTS The group with bone pain had higher serum concentrations of phosphate (6.2 +/- 1.4 mg/dl vs 4.9 +/- 1.1 mg/dl, p = 0.012) and urea (136.0 +/- 37.4 mg/dl vs 111.3 +/- 23.5 mg/dl, p = 0.035) than the group without bone pain. After adjustment of results to gender, age and dialysis vintage these differences remained significant, additionally the group with bone pain had higher serum creatinine concentration than the group without bone pain (9.5 +/- 2.4 mg/dl vs 7.5 +/- 2.9 mg/dl, p = 0.009). There were no statistically significant differences between groups in BMD measured in N and L2-L4. CONCLUSION Our results suggest that bone pain in dialysis patients is associated rather with serum concentration of small uremic toxins than with BMD.