Comparable case finding percentages of osteoporosis despite diverging reasons for ordering bone densitometry by general practitioners and specialists

OBJECTIVE: To assess the use of bone densitometry in practice. DESIGN: Retrospective. METHOD: General practitioners who had ordered bone densitometry for their patients were asked to fill in a questionnaire on the reasons for the request and the subsequent treatment they prescribed. For a similar number of patients from the outpatient clinics of general internal medicine and endocrinology, the medical records were examined to obtain the same information. RESULTS: In 9 months, general practitioners requested 150 bone density measurements; for 117 of these the data were complete. In one year, 150 measurements were requested by the outpatient clinics. Marked differences in the reasons for the request were seen in loss of body height, back pain and requests from the patient (indications for general practitioners) and in osteoporotic fractures and the use of corticosteroids (indications for specialists). The average result of the measurements, however, was the same, with mean T-scores in the lumbar spine of -2.26 and -2.19, respectively and case-finding percentages of osteoporosis of 21% on the basis of the lumbar spine and 40% on the basis of the spine or hip. Bone densitometry carried out after an osteoporotic fracture was associated with the lowest mean bone mineral density, followed by measurement on the basis of abnormal X-rays. Bone densitometry at the patient's request was associated with the highest bone density. The percentage of patients found to have osteoporosis turned out to be dependent on the site of measurement, the used reference ranges, and the method of reporting, especially for patients older than 70 years. When the bone density corresponded to a diagnosis of osteoporosis, nearly all patients were treated, mainly with a bisphosphonate. Treatment was also frequently started when the bone density was reduced, i.e. in case of osteopenia. Some patients with normal bone density were treated as well. The reason for such treatment was not always clear. CONCLUSION: General practitioners and specialists used different risk factors in deciding whether bone densitometry was indicated. However, the two groups used this diagnostic tool with equal efficiency, since both the percentages of osteoporosis detected and the average bone densities were the same.