In HD patients with 24-hour urine volume > 100ml, the AUC of FGF21 combined with age in predicting osteoporosis was 0.837 (95 % CI, 0.778 to 0.896, P < 0.001) with better sensitivity (70.1 %) and specificity (81.4 %). This evidence concerns the gene FGF21 and osteoporosis.