Evaluation of bone disease in multiple myeloma: a comparison between the resorption markers urinary deoxypyridinoline/creatinine (DPD) and serum ICTP, and an evaluation of the DPD/osteocalcin and ICTP/osteocalcin ratios.

Markers of bone metabolism were measured in 73 newly diagnosed myeloma patients and in age-matched controls. Correlations to bone disease on X-rays and survival were performed. In urine deoxypyridinoline/creatinine (DPD) and in serum carboxyterminal pyridinoline cross-linked telopeptide of type I collagen (ICTP), procollagen type I carboxy-terminal extension peptide (PICP) and osteocalcin were analyzed. The ratios DPD/osteocalcin and ICTP/osteocalcin were calculated. Skeletal X-ray findings were divided into no, limited and extensive bone involvement. DPD and ICTP levels were significantly elevated in patients compared to controls. Levels increased with advancing skeletal involvement. Serum osteocalcin was elevated in patients without visible bone disease. The level decreased with more advanced bone involvement. The finding of significantly elevated osteocalcin and ICTP levels in patients without bone involvement on X-rays indicates that bone markers might reflect bone disease better than X-rays in untreated myeloma patients. Ratios between bone resorption and bone formation markers added no further information on bone disease or survival. Only ICTP had prognostic value with an inverse correlation between serum levels and survival.