BACKGROUND

CMS Star Ratings help inform beneficiaries about the performance of health and drug plans. Medication adherence is currently weighted at nearly half of a Part D plan's Star Ratings. Including the adherence to non-vitamin-K-antagonist oral anticoagulants (NOACs) as a measure in the Star Ratings program may increase a plan's incentives to improve patient adherence.

OBJECTIVE

To assess the adherence to medication of patients who used the NOACs rivaroxaban, dabigatran, or apixaban in 2014 based on the Pharmacy Quality Alliance (PQA) adherence measure.

METHODS

Healthcare claims from the Humana database between July 2013 and December 2014 were analyzed. Adult patients with ≥2 dispensings of NOAC agents in 2014, at least 180 days apart, with >60 days of supply, and ≥180 days of continuous enrollment prior to the index NOAC were identified. The PQA measure was calculated as the percentage of patients who had a proportion of days covered (PDC) ≥0.8. Multivariate logistic regression analyses were also conducted adjusting for baseline confounders.

RESULTS

A total of 11,095 rivaroxaban, 6548 dabigatran, and 3532 apixaban users were identified. Based on the PQA adherence measure (PDC ≥0.8), a significantly higher proportion of rivaroxaban users (72.7%) was found to be adherent compared to dabigatran (67.2%: p < 0.001) and apixaban (69.5%: p < 0.001) users. Compared to apixaban users, the adjusted likelihood of being adherent was significantly higher for rivaroxaban users (unadjusted OR [95% CI]: 1.17 [1.08-1.27], p < 0.001; adjusted OR [95% CI]: 1.20 (1.10-1.31), p < 0.001) and significantly lower for dabigatran users (unadjusted OR [95% CI]: 0.90 [0.82-0.98], p = 0.019; adjusted OR [95% CI]: 0.85 [0.77-0.93], p < 0.001).

LIMITATIONS

Limitations of the study are potential inaccuracies in claims data, possible change in patterns over time, and the impossibility of knowing whether all supplied tablets were taken.

CONCLUSION

Using the PQA's adherence measure, rivaroxaban users were found to have significantly higher adherence compared to apixaban and dabigatran users.