Background Although the tendency to repeat examinations is a major determinant of the capacity to serve new patients and of the ability to contain health care costs, little research has described the patterns observed in actual practice.
Methods We investigated patterns of repeat testing in a longitudinal study of a 5% random sample of Medicare beneficiaries, restricted to 743 478 fee-for-service patients who were alive for a 3-year period after their index test between January 1, 2004, and December 31, 2006. Using the 50 largest metropolitan statistical areas as the unit of analysis, we examined the relationship between the proportion of the population tested and the proportion of tests repeated among those tested.
Results Among beneficiaries undergoing echocardiography, 55% had a second test within 3 years. Repeat testing following other examinations was also common: 44% of imaging stress tests were repeated within 3 years, as were 49% of pulmonary function tests, 46% of chest computed tomography, 41% of cystoscopies, and 35% of upper endoscopies. The proportion of the population tested and the proportion of tests repeated varied across metropolitan statistical areas. The proportion who underwent echocardiography was highest in Miami, Florida (48%, among whom 66% of examinations were repeated in 3 years), and was lowest in Portland, Oregon (18%, among whom 47% of examinations were repeated in 3 years). Across 50 metropolitan statistical areas, the proportion of the population tested was consistently positively correlated with the proportion of tests repeated for echocardiography (Spearman r = 0.87, P < .001), imaging stress test (r = 0.65, P < .001), pulmonary function test (r = 0.62, P < .001), chest computed tomography (r = 0.66, P < .001), cystoscopy (r = 0.21, P = .13), and upper endoscopy (r = 0.59, P < .001).
Conclusions Repeat testing is common among Medicare beneficiaries. Patients residing in metropolitan statistical areas with high rates of population testing are more likely to be tested and are more likely to have their test repeated.