Evaluation of some biochemical and radiological changes in bone metabolism during corticosteroid therapy

ABSTRACT

Osteoporosis is considered as a major outcome of corticosteroid administration. The evaluation of the degree of osteoporosis in patients on steroid therapy was examined by many studies. This work aimed at the assessment of bone turnover markers, as well as, quantitative computed tomography as measures for detection of osteoporosis in patients receiving corticosteroids. This has been achieved through the biochemical detection of bone turnover markers [total alkaline phosphatase [SAP], osteocalcin [OC], urinary excretion of hydroxyproline/creatinine [OHPr/Cr]] and QCT scanning of L[2]-L[4] Vertebrae. Our results demonstrated that 60% of patients on steroids had complaints related to osteoporosis. Concerning the biochemical parameters of bone turnover SAP tended to be higher in patients than in control. Also, OC is significantly reduced [P bone formation. Urinary excretion of hydroxyproline/creatinine [OHPr/Cr] was significantly higher in patients than control [P bone resorption. When patients were subdivided according to the dosage and/or the duration of steroid intake, no significant correlation could be elicited among each 2 groups of patients and the different biochemical parameters of bone turnover. By using QCT, all patients were considered osteoporotic, and 50% of the osteoporotic patients were on high dosage steroids for a long duration. Yet, we failed to detect any correlation between the degree of osteoporosis in terms of Z-score of BMD, and the different biochemical markers of bone turnover. In conclusion, it appears that osteoporosis may be a completely silent condition. Although, the biochemical markers used in the study reflect bone turnover, QCT, as a tool in measuring BMD, could be considered a more sensitive parameter in early detection of asymptomatic osteoporosis