Choosing Wisely Canada campaign associated with less overuse of thyroid testing: Retrospective parallel cohort study.

OBJECTIVE: To assess the effectiveness of a Choosing Wisely Canada (CWC) initiative to improve thyroid-stimulating hormone (TSH) test ordering for patients with no identified indication for this test.
DESIGN: Retrospective parallel cohort study using routinely collected electronic medical record (EMR) data. The CWC initiative included supporting primary care leads in each participating family health team, providing education on better test ordering, and allowing adaptation appropriate to each local context.
SETTING: Toronto, Ont, and surrounding areas. PARTICIPANTS: Family physicians contributing EMR data to the University of Toronto Practice-Based Research Network and their patients aged 18 or older. MAIN OUTCOME MEASURES: Proportion of adult patients with a TSH test done in a 2-year period (2016 to 2017) in the absence of EMR data with an indication for TSH testing; proportion of TSH test results in the normal range for those patients; and change in the rate of TSH screening in sites participating in the CWC initiative compared with sites not participating.
RESULTS: A total of 150 944 patients (51.7% of studied adults) had no identified indication for TSH testing; 33.4% of those patients were seen by physicians in the family health teams participating in the CWC initiative. Overall, 35.1% of all patients with no identified indication had at least 1 TSH test between January 1, 2016, and December 31, 2017. The 119 physicians participating in the CWC initiative decreased their monthly rate of testing by 0.23% from 2016 to 2017, a relative reduction of 13.2%. The 233 physicians not participating decreased testing by 0.04%, a relative reduction of 1.8%. The monthly difference between the 2 groups was 0.19% (95% CI -0.02 to -0.35 P = .03), a relative difference of 11.4%. The TSH testing decreased for almost all CWC patient subgroups. More than 95% of patients tested in both groups had TSH results in the normal range.
CONCLUSION: This study found high rates of TSH testing without identified indications in the practices studied. A CWC initiative implemented in primary care was effective in reducing TSH testing. Copyright© the College of Family Physicians of Canada.