A world of uncertainties
Cardiologists rely on evidence from clinical trials to make treatment decisions yet the evidence may be in discord with what they encounter in practice. And in practice, they may be reluctant to stick with the selection criteria used in clinical trials.
That quandary came to light in two different studies that addressed different aspects of cardiovascular care. In one study, researchers used registry data to compare patients who were eligible for inclusion in trials with those who participated as well as ineligible patients. The other study assessed insurance claims data to identify trends in the use of warfarin or one of the three approved novel anticoagulants.
On the one hand, it appears that the participants enrolled in cardiovascular clinical trials may not be an accurate representation of the MI patient population as a whole. They are generally healthier, younger and have a more favorable prognosis than those not included in trial samples, according to the analysis.
And on the other hand, physicians may be taking a conservative approach when prescribing novel oral anticoagulants to reduce the risk of stroke in patients with nonvalvular atrial fibrillation. Physicians may be selecting healthier patients for these treatments rather than the ones who might benefit the most from these options.
Researchers found that prescriptions for dabigatran (Pradaxa, Boehringer Ingelheim), rivaroxaban (Xarelto, Janssen Pharmaceuticals/Bayer HealthCare) and apixaban (Eliquis, Bristol-Myers Squibb and Pfizer) now outpace warfarin, but the patients prescribed these drugs tended to be younger, healthier with lower CHADS2 and HAS-BLED scores compared with warfarin users.
Both studies also raised other concerns. The analysis of clinical trial populations showed participation in trials declining over time, from 5.2 percent of the patients whose data was submitted to the registry in 2008 to 3.4 percent in 2011. Recruiting patients into randomized controlled clinical trials can be time consuming and expensive, which puts such endeavors in jeopardy.
The authors of the anticoagulant study also determined that the six-month cost to patients and payers for novel anticoagulants vs. warfarin came to $900 per patient, which “in our cohort translates into billions of dollars at a national level.”
Physicians may be reluctant to counsel patients they see as higher risk to join trials. Earlier reports of bleeding risks with novel anticoagulants—dabigatran, in particular—may have steered physicians along the conservative path. Until they are reassured otherwise, these is patterns are likely to persist.
Candace Stuart
Cardiovascular Business, editor
cstuart@cardiovascularbusiness.com