The impact of the Choosing Wisely Canada campaign on the simultaneous use of angiotensin-converting-enzyme inhibitors and angiotensin receptor blockers: interrupted time-series analysis.

Background: Choosing Wisely is a high-profile campaign seeking to reduce the use of low-value care. We investigated the impact of a Choosing Wisely Canada recommendation against using a combination of angiotensin-converting-enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) for the management of hypertension, heart failure or diabetic nephropathy on population-level use of these medications in British Columbia, Canada.

Methods: We identified all people (any age) who were continuously registered with BC's Medical Service Plan between 2010 and 2017 with the targeted conditions. Using prescription claims data and an interrupted time-series analysis, we estimated the number of people on combination therapy per month, the proportion of days covered (PDC) by combination therapy per month and proportion of all combination prescriptions started per month in the 2 years before and after the introduction of the recommendation on Oct. 29, 2014.

Results: Of 1 104 593 people (mean age 65 yr, standard deviation 16 yr) in our study cohort, 4.6% were exposed to combination therapy, largely prescribed by family physicians (84%). The number of people on combination therapy and the PDC were declining before the recommendation, but the proportion of combination prescriptions started in the 2 years before the recommendation was increasing. After the recommendation, we observed no statistically significant changes in any outcome. The pre-existing downward trend of the monthly number of people decelerated (16.8, 95% confidence interval [CI] 14.0 to 19.5) and the proportion of prescriptions started increased (0.13%, 95% CI 0.08% to 0.18%).

Interpretation: The Choosing Wisely Canada recommendation against using a combination of ACE inhibitors and ARBs was not associated with reduced combination therapy use in the targeted conditions. The observed pre-existing declines in this practice questions the process of selecting recommendations, and the optimal implementation and value of Choosing Wisely campaigns without other reinforcing interventions.