Background: Measurement of bone mineral density is widely used to diagnose osteoporosis. The objectives of this study are to determine how bone densitometry affects subsequent treatment of osteopenia and osteoporosis with either hormone replacement therapy or bisphosphonates and to examine clinical factors associated with starting either therapy after bone densitometry.
Methods: We conducted a prospective study involving women over 50 years of age who were referred to a tertiary care hospital for the first time to undergo bone density measurement using dual-energy x-ray absorptiometry (DXA). Baseline clinical data were collected through face-to-face interviews before the test. Subsequently, the scans were reviewed and categorized as showing no bone loss, osteopenia or osteoporosis, based on World Health Organization criteria. Three months after DXA, subjects were contacted by telephone to determine their understanding of the test results and any new treatments started or recommended since the scan.
Results: Of 383 women recruited at the time of their DXA, 335 (87.5%) completed the 3-month follow-up. Among those reached at follow-up, DXA results showed no bone loss in 119 (35.5%), osteopenia in 137 (40.9%) and osteoporosis in 79 (23.6%). The proportion of subjects with osteoporosis receiving either hormone replacement therapy or bisphosphonate therapy was 15.2% before the test, increasing to 63.3% after the scan. The following factors were independently associated with the initiation of either therapy: actual DXA result showing osteoporosis (odds ratio [OR] 7.2; 95% confidence interval [CI] 1.7-30.3), compared with a normal scan; subjects' perception that their scan showed bone loss (osteopenia, or osteoporosis) (OR 13.5; 95% CI 4.0-45.5) or that they were unclear about the results (OR 5.4; 95% CI 1.6-18.8), compared with the perception that the results were normal; and discussion of the DXA results with a physician (OR 5.5; 95% CI 1.9-16.0).
Interpretation: The proportion of women with osteoporosis receiving hormone replacement therapy or bisphosphonate therapy increases after diagnosis with densitometry. However, communication by physicians so that patients understand their test results is a critical component in the initiation of therapy after bone densitometry.