[Modifications in diagnosis and therapy of osteoporosis after bone densitometry]

The cost-benefit ratio of diagnostic procedures has become a major problem: in particular, the expense of computerized bone mineral densitometry for osteoporosis diagnosis has brought this issue to public attention. To avoid a procedure considered costly, non-specialists often rely on standard radiography alone for diagnosis. In this study, we evaluated the percent of cases in which densitometry modified diagnosis and therapy based solely on radiographic findings. Over a 10-month period, we recruited 133 consecutive post-menopausal patients (average age 58.3 years, average time since menopause 12 years) who had never undergone densitometry. Bone density at the lumbar (L1-L4) or femoral (non-dominant) level was measured with dual energy X-ray absorptiometry. The average time between densitometry and the last radiographic examination was 13.6 months. Ninety-one patients (68.4%) had a change in diagnosis following densitometry. In 42 cases (31.6%), the previous diagnosis remained unchanged (prevalence ratio 2.2; 95% confidence interval 1.6 to 2.7). Therapy was changed in 75.2% of the cases (100 patients) and remained the same in 24.8% (33 patients; prevalence ratio 3.0; 95% confidence interval 2.3 to 3.7). Our data underscore the importance of densitometry in yielding quantitative data that are utilizable during follow-up and able to support osteoporosis diagnosis and therapy.