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Canadian Journal of Cardiology

Impact of Drug Plans on Adherence to and the Cost of Antihypertensive Medications Among Patients Covered by a Universal Drug Insurance Program

Published:December 11, 2013DOI:https://doi.org/10.1016/j.cjca.2013.11.032

      Abstract

      Background

      This study aimed to assess the impact of the type of drug plan on adherence to antihypertensive medication treatment as well as the cost of these medications within universal drug insurance programs.

      Methods

      To compare adherence to antihypertensive medication treatment and the cost of antihypertensive medications between adults with public and private drug insurance in the province of Québec, Canada, we reconstructed a matched retrospective cohort by linking data recorded in 3 administrative databases between March 2008 and May 2010. The cohort included 186 privately and 1747 publicly insured patients aged 18-64 years who were treated with 1 or 2 antihypertensive medications. Adherence measured with the proportion of days covered (PDC) over 1 year and the cost of antihypertensive medications were evaluated for new and prevalent users separately.

      Results

      More than 70% of patients were 50-64 years old and 90% of the publicly and 72% of the privately insured patients were using only 1 antihypertensive medication. The mean PDC among new users of 1 antihypertensive medication was 58.8% for privately insured patients and 65.0% for publicly insured patients, but the difference was not statistically significant. However, privately insured patients treated with 2 antihypertensive medications were more likely to be adherent (PDC-P, 15.0%; 95% confidence interval, 7.0-24.0). Privately insured patients (CAD$41.52) had to pay significantly more for their antihypertensive medications than did publicly insured patients (CAD$32.21).

      Conclusions

      The cost of antihypertensive medications was higher for patients with private drug insurance, although adherence was similar in both groups. The results may reflect regulation of dispensing fees for publicly insured patients.

      Résumé

      Introduction

      Cette étude a pour but d’évaluer l'impact du type de régime d’assurance médicaments sur l’observance du traitement médicamenteux contre l’hypertension ainsi que sur le coût de ces médicaments dans le cadre des programmes universels d’assurance médicaments.

      Méthodes

      Pour comparer l’observance du traitement médicamenteux contre l’hypertension et le coût des médicaments antihypertenseurs entre les adultes couverts par un régime public d’assurance médicaments et ceux couverts par un régime privé d’assurance médicaments de la province de Québec, au Canada, nous avons reconstitué une cohorte rétrospective appariée en reliant les données enregistrées de 3 bases de données administratives entre mars 2008 et mai 2010. La cohorte incluait 186 patients de 18 à 64 ans couverts par un régime public d’assurance et 1747 patients couverts par un régime privé d’assurance qui étaient traités par 1 ou 2 médicaments antihypertenseurs. L’observance mesurée par la proportion de jours couverts (PDC) durant 1 année, et le coût des médicaments antihypertenseurs ont été évalué séparément chez les nouveaux utilisateurs et les utilisateurs prévalents.

      Résultats

      Plus de 70 % des patients étaient âgés de 50 à 64 ans, et 90 % des patients couverts par un régime public d’assurance et 72 %, par un régime privé d’assurance utilisaient seulement 1 médicament hypertenseur. La PDC moyenne parmi les nouveaux utilisateurs de 1 médicament hypertenseur était de 58,8 % chez les patients couverts par un régime privé d’assurance et de 65,0 % chez les patients couverts par un régime public d’assurance, mais la différence n’était pas statistiquement significative. Cependant, les patients couverts par un régime privé d’assurance qui étaient traités par 2 médicaments antihypertenseurs étaient plus susceptibles de respecter l'observance (PDC-P, 15,0 %; intervalle de confiance à 95 %, 7,0-24,0). Les patients couverts par un régime d’assurance privé (41,52 $ CA) devaient payer leurs médicaments antihypertenseurs beaucoup plus chers que les patients couverts par un régime public d’assurance (32,21 $ CA).

      Conclusions

      Le coût des médicaments antihypertenseurs était plus élevé chez les patients couverts par un régime privé d’assurance médicaments, quoique l’observance ait été similaire dans les deux groupes. Les résultats peuvent être le reflet de la réglementation des honoraires du pharmacien chez les patients couverts par un régime public d’assurance.
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