[Use of bone densitometry in the framework of prevention and therapy of osteoporosis. Example of a systematic evaluation (health technology assessment)].

There is an ongoing controversy concerning the use of bone density measurements within therapeutic and preventive strategies of osteoporosis. Since there are no randomized controlled trials evaluating the effectiveness of bone density measurement with subsequent therapy we used a "critical pathway" model to determine possible benefit of tertiary, secondary and primary preventive strategies utilizing bone density measurement. In a first step data for fracture risk in each group are extracted from the literature. The second step outlines possible benefit from therapeutic studies. It may be estimated that in groups of patients with prevalent fractures use of bone density measurement and therapy according to bone density values may reduce fracture rates up to 30%. Bone density measurements performed with secondary preventive intent, however will probably lead to a reduction of fracture rates markedly below 10%. A set of risk factors that allows identification of a high risk group that may benefit from bone density measurement and subsequent therapy to a relevant extent remains to be developed. Primary preventive strategies do not require bone density measurements.