Urinary bone resorption markers (deoxypyridinoline and C-terminal telopeptide of type I collagen) in healthy persons, postmenopausal osteoporosis and patients with type I diabetes.

PURPOSE: Deoxypyridinoline (DPD) is a derivative of hydroxypyridinium, which is released during bone resorption into the blood stream and is eliminated unmodified with urine. A further collagen-derived marker of bone resorption is the C-terminal telopeptide of type I collagen (beta-CTX-I, here abbreviated as CTX), which is released in bone resorption and almost entirely excreted by the kidneys. The aim of our study was to investigate different well-described patient groups as well as normal probands in view of differences and expected correlations of these two parameters: patients with insulin-dependent diabetes mellitus, postmenopausal women with osteoporosis and healthy control persons.

MATERIALS AND METHODS: We used a solid-phase chemiluminescence enzyme immunoassay (Pyrilinks D-IMMULITE) for urinary DPD measurement and for the assessment of urinary CTX we used a quantitative ELISA (Osteometer Biotec A-S, CrossLaps ELISA).

RESULTS: We found a highly significant correlation between both parameters in the group of healthy persons (r = 0.75, p < 0.05, n = 28) as well as in the group of patients with diabetes mellitus type I (r = 0.79, p < 0.05, n = 65). Also, a significant correlation was observed between DPD and CTX (r = 0.583, p < 0.05, n = 88) in the group of female osteoporotic patients.

CONCLUSIONS: Despite good correlations between DPD and CTX in all of the investigated groups, these urinary markers were of limited diagnostic significance in the group of postmenopausal osteoporosis due to a wide spread (few patients showed concentrations above the range of healthy persons) in this newly diagnosed drug-naïve patient collective.