Patterns of use of the bone mineral density test in Ontario, 1992-1998

Background: There is ongoing controversy about who should be referred for b one mineral density (BMD) testing to estimate fracture risk and diagnose os teoporosis. The purpose of this study was to examine patterns of use of BMD testing in Ontario between 1992 and 1998. Methods: All physician claims from the Ontario Health Insurance Plan (OHIP) claims database for BMD testing between Jan. 1, 1992, and Dec. 31, 1998, w ere categorized by age and sex of the patient and the specialty of the phys ician who ordered the test. Time trends and regional rate variation analyse s were also performed. To examine the prevalence of repeat testing, an ince ption cohort of women who had a BMD test in 1996 was followed for 2 years f rom the date of first test. Results: From 1992 to 1998 the number of BMD tests performed per year in wo men increased from 34 402 to 230 936 and in men from 2 162 to 13 579. In 19 98 most tests were being ordered by family physicians (80.2% in 1998 v. 52. 1% in 1992). Approximately 1 in 7 women aged 55-69 years had BMD tests done in 1998. Within a 2-year period 29.3% of these women had the test repeated ; the mean time between tests was 16 months. Regional rate variation analys es of BMD tests performed in 1996-1998 indicated a 235-fold variation in BM D test rates across counties in Ontario, with a range from 0.2 to 47.1 per 1000 women in the population. Interpretation: The number of BMD tests performed each year in Ontario is i ncreasing rapidly. However, the significant variation between rates of test ing in different regions indicates that the diffusion of this technology ma y not be taking place according to population need.