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:



      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.


      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.


      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).


      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.



      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.


      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.


      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).


      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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        • Dai S.
        • Robitaille C.
        • Bancej C.
        • et al.
        Executive summary—report from the Canadian Chronic Disease Surveillance System: hypertension in Canada, 2010.
        Chronic Dis Can. 2010; 31: 46-47
        • Lloyd-Jones D.
        • Adams R.J.
        • Brown T.M.
        • et al.
        Heart disease and stroke statistics—2010 update: a report from the American Heart Association.
        Circulation. 2010; 121: 46-215
        • Walker R.L.
        • Chen G.
        • Campbell N.R.
        • et al.
        Canadian provincial trends in antihypertensive drug prescriptions between 1996 and 2006.
        Can J Cardiol. 2011; 27: 461-467
        • Joffres M.R.
        • Campbell N.R.
        • Manns B.
        • Tu K.
        Estimate of the benefits of a population-based reduction in dietary sodium additives on hypertension and its related health care costs in Canada.
        Can J Cardiol. 2007; 23: 437-443
        • Sokol M.C.
        • McGuigan K.A.
        • Verbrugge R.R.
        • Epstein R.S.
        Impact of medication adherence on hospitalization risk and healthcare cost.
        Med Care. 2005; 43: 521-530
        • Ho P.M.
        • Magid D.J.
        • Shetterly S.M.
        • et al.
        Medication nonadherence is associated with a broad range of adverse outcomes in patients with coronary artery disease.
        Am Heart J. 2008; 155: 772-779
        • Rizzo J.A.
        • Simons W.R.
        Variations in compliance among hypertensive patients by drug class: implications for health care costs.
        Clin Ther. 1997; 19: 1446-1457
        • Dragomir A.
        • Cote R.
        • Roy L.
        • et al.
        Impact of adherence to antihypertensive agents on clinical outcomes and hospitalization costs.
        Med Care. 2010; 48: 418-425
        • Jing S.
        • Naliboff A.
        • Kaufman M.B.
        • Choy M.
        Descriptive analysis of mail interventions with physicians and patients to improve adherence with antihypertensive and antidiabetic medications in a mixed-model managed care organization of commercial and Medicare members.
        J Manag Care Pharm. 2011; 17: 355-366
        • Zeng F.
        • Patel B.V.
        • Andrews L.
        • Frech-Tamas F.
        • Rudolph A.E.
        Adherence and persistence of single-pill ARB/CCB combination therapy compared to multiple-pill ARB/CCB regimens.
        Curr Med Res Opin. 2010; 26: 2877-2887
        • Chang J.
        • Yang W.
        • Kahler K.H.
        • et al.
        Compliance, persistence, healthcare resource use, and treatment costs associated with aliskiren plus ARB versus ACE inhibitor plus ARB combination therapy: in US patients with hypertension.
        Am J Cardiovasc Drugs. 2011; 11: 21-32
        • Steiner J.F.
        • Ho P.M.
        • Beaty B.L.
        • et al.
        Sociodemographic and clinical characteristics are not clinically useful predictors of refill adherence in patients with hypertension.
        Circ Cardiovasc Qual Outcomes. 2009; 2: 451-457
        • Lamb D.A.
        • Eurich D.T.
        • McAlister F.A.
        • et al.
        Changes in adherence to evidence-based medications in the first year after initial hospitalization for heart failure: observational cohort study from 1994 to 2003.
        Circ Cardiovasc Qual Outcomes. 2009; 2: 228-235
        • Shah N.D.
        • Dunlay S.M.
        • Ting H.H.
        • et al.
        Long-term medication adherence after myocardial infarction: experience of a community.
        Am J Med. 2009; 122: 961.e7-961.e13
        • Québec RDLAMD
        Rapport annuel de gestion 2010-2011.
        Régie de l'assurance maladie du Québec, 2011
        • Hess L.M.
        • Raebel M.A.
        • Conner D.A.
        • Malone D.C.
        Measurement of adherence in pharmacy administrative databases: a proposal for standard definitions and preferred measures.
        Ann Pharmacother. 2006; 40: 1280-1288
        • Karve S.
        • Cleves M.A.
        • Helm M.
        • et al.
        Good and poor adherence: optimal cut-point for adherence measures using administrative claims data.
        Curr Med Res Opin. 2009; 25: 2303-2310
        • Bramley T.J.
        • Gerbino P.P.
        • Nightengale B.S.
        • Frech-Tamas F.
        Relationship of blood pressure control to adherence with antihypertensive monotherapy in 13 managed care organizations.
        J Manag Care Pharm. 2006; 12: 239-245
        • Bangalore S.
        • Kamalakkannan G.
        • Parkar S.
        • Messerli F.H.
        Fixed-dose combinations improve medication compliance: a meta-analysis.
        Am J Med. 2007; 120: 713-719
        • Gupta A.K.
        • Arshad S.
        • Poulter N.R.
        Compliance, safety, and effectiveness of fixed-dose combinations of antihypertensive agents: a meta-analysis.
        Hypertension. 2010; 55: 399-407
        • Sherrill B.
        • Halpern M.
        • Khan S.
        • Zhang J.
        • Panjabi S.
        Single-pill vs free-equivalent combination therapies for hypertension: a meta-analysis of health care costs and adherence.
        J Clin Hypertens (Greenwich). 2011; 13: 898-909
        • Choudhry N.K.
        • Avorn J.
        • Glynn R.J.
        • et al.
        Full coverage for preventive medications after myocardial infarction.
        N Engl J Med. 2011; 365: 2088-2097
        • Eaddy M.T.
        • Cook C.L.
        • O'Day K.
        • Burch S.P.
        • Cantrell C.R.
        How patient cost-sharing trends affect adherence and outcomes: a literature review.
        P T. 2012; 37: 45-55
        • Goldman D.P.
        • Joyce G.F.
        • Zheng Y.
        Prescription drug cost sharing: associations with medication and medical utilization and spending and health.
        JAMA. 2007; 298: 61-69
        • Maciejewski M.L.
        • Bryson C.L.
        • Perkins M.
        • et al.
        Increasing copayments and adherence to diabetes, hypertension, and hyperlipidemic medications.
        Am J Manag Care. 2010; 16: 20-34
        • Yoon J.
        • Ettner S.L.
        Cost-sharing and adherence to antihypertensives for low and high adherers.
        Am J Manag Care. 2009; 15: 833-840
        • Khan N.A.
        • Hemmelgarn B.
        • Herman R.J.
        • et al.
        The 2009 Canadian Hypertension Education Program recommendations for the management of hypertension: part 2—therapy.
        Can J Cardiol. 2009; 25: 287-298
        • Kressin N.R.
        • Orner M.B.
        • Manze M.
        • Glickman M.E.
        • Berlowitz D.
        Understanding contributors to racial disparities in blood pressure control.
        Circ Cardiovasc Qual Outcomes. 2010; 3: 173-180
        • Friedman O.
        • McAlister F.A.
        • Yun L.
        • Campbell N.R.
        • Tu K.
        Antihypertensive drug persistence and compliance among newly treated elderly hypertensives in Ontario.
        Am J Med. 2010; 123: 173-181
        • Meneton P.
        • Lanoe J.L.
        • Menard J.
        Health insurance coverage is the single most prominent socioeconomic factor associated with cardiovascular drug delivery in the French population.
        J Hypertens. 2012; 30: 617-623
        • Tamblyn R.
        • Lavoie G.
        • Petrella L.
        • Monette J.
        The use of prescription claims databases in pharmacoepidemiological research: the accuracy and comprehensiveness of the prescription claims database in Quebec.
        J Clin Epidemiol. 1995; 48: 999-1009