Irish cardiologist highlights implementation gap between clinical trials and routine care in NEJM editorial

Professor Robert Byrne, Director of Cardiovascular Research Institute Dublin and Director of Cardiology at Mater Private Network, has highlighted the importance of pragmatic implementation trials in assessing how evidence-based treatment policies perform in routine care.

Writing in the New England Journal of Medicine, Professor Byrne examines the SWITCH-SWEDEHEART trial, a registry-based, stepped-wedge, cluster-randomised study of antiplatelet treatment policy in patients with acute coronary syndrome.

The trial involved seven Swedish healthcare regions transitioning their default treatment policy from ticagrelor to prasugrel.

At one year, there was no statistically significant difference in the composite rate of death, myocardial infarction or stroke between the prasugrel-policy and ticagrelor-policy groups, at 11.1% and 11.8% respectively.

However, adherence to the respective treatment policies was incomplete. Prasugrel was dispensed to 61% of patients in the prasugrel-policy group, while ticagrelor was dispensed to 76% of patients in the ticagrelor-policy group. Most patients who did not receive the policy-recommended treatment received clopidogrel instead.

Professor Byrne said the findings demonstrate the value of studying how treatment recommendations are implemented in routine clinical practice:

“Randomised clinical trials remain fundamental to determining the safety and efficacy of treatments, but they do not answer every question about how those treatments will be used in everyday care.

“Pragmatic implementation trials can provide complementary evidence by showing what happens when treatment policies are introduced across healthcare systems, where prescribing decisions may differ from the default recommendation.”

Previous randomised evidence had indicated an advantage for prasugrel over ticagrelor in certain patients with acute coronary syndrome undergoing percutaneous coronary intervention.

In SWITCH-SWEDEHEART, that advantage was less evident when the treatment policy was implemented in routine care. A substantial proportion of patients received an alternative antiplatelet treatment, which may have reduced the difference between the policy groups.

Professor Byrne has described SWITCH-SWEDEHEART as a landmark policy implementation trial in cardiovascular medicine and says the findings support a greater role for pragmatic, registry-based randomised trials of approved therapies.

“The implementation gap between controlled clinical trials and routine practice is real,” Professor Byrne said.

“For clinicians, guideline developers and policymakers, the question is not only whether a treatment works under trial conditions, but whether the expected benefits are realised when treatment strategies are implemented in practice.”