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

BACKGROUND

There is ongoing controversy about who should be referred for bone mineral density (BMD) testing to estimate fracture risk and diagnose osteoporosis. 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, were categorized by age and sex of the patient and the specialty of the physician who ordered the test. Time trends and regional rate variation analyses were also performed. To examine the prevalence of repeat testing, an inception cohort of women who had a BMD test in 1996 was followed for 2 years from the date of first test.

RESULTS

From 1992 to 1998 the number of BMD tests performed per year in women increased from 34,402 to 230,936 and in men from 2,162 to 13,579. In 1998 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 analyses of BMD tests performed in 1996-1998 indicated a 235-fold variation in BMD 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 increasing rapidly. However, the significant variation between rates of testing in different regions indicates that the diffusion of this technology may not be taking place according to population need.