The University of Mississippi School of Pharmacy

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1 LONG TERM PERSISTENCE WITH ACEI/ARB THERAPY AFTER ACUTE MYOCARDIAL INFARCTION: AN ANALYSIS OF THE MEDICARE 5% NATIONAL SAMPLE DATA Lokhandwala T. MS, Yang Y. PhD, Thumula V. MS, Bentley J.P. PhD, Banahan B.F. PhD, Strum M. PharmD, Null K.D. PharmD, MS. ISPOR 16 th Annual International Meeting 2011 The University of Mississippi School of Pharmacy

2 Outline Study Context Objectives Methods Results Limitations, Implications and Future Research

3 Background Cardiovascular diseases (CVD) remain the leading cause of death in the U.S. However, from 1997 to 2007 deaths due to CVD declined by 27.8%. Approximately 1.3 million Americans are estimated to suffer from an acute myocardial infarction (MI) event each year. From 1997 to 2007 the total number of inpatient cardiovascular operations and procedures increased 27%. Direct and indirect costs due to CVDs are more than that of any other diagnostic group. Death rates due to CVD have declined, yet the burden of the disease remains high. NCHS 2009; Heart Disease and Stroke Statistics 2010.

4 Treatment and Prevention Practice guidelines from the American Heart Association (AHA) & the American College of Cardiology (ACC) recommend that post-mi patients receive treatment with a Beta-blocker Lipid lowering agent Angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) Aspirin Due to large scales efforts nationwide more patients are being prescribed effective pharmacotherapy at discharge (Williams et al. 2005; Choudhry et al. 2007). However, poor long-term adherence to post-mi medications has been documented (Benner et al. 2002). Fairly healthy and young patients with modest co-pays and no documented contraindications have also been observed to have high rates of non-adherence (Ackincigil et al. 2008). Adherence is of particular importance to the elderly as the prevalence of CHD and the risk of mortality increase with age (Antman et al. 2000).

5 Research Objectives To study the pattern of discontinuation of ACEI/ARB therapy among post MI patients enrolled in the part D benefits of Medicare. To identify patient characteristics and comorbidities associated with ACEI/ARB therapy discontinuation among post MI patients enrolled in the part D benefits of Medicare.

6 METHODS

7 Study Design Retrospective observational study using Medicare 5% national sample data. Claims from 1 st Jan 2006 to 31 st Dec 2007 were analyzed. Identification of subjects Jan 2006 Jul 2006 Jan 2007 Dec 2007 Observation of outcome Fig Graphical representation of the study period

8 Identification of MI Patients 9870 subjects A hospitalization episode lasting at least 3 days and not more than 180 days with an ICD-9-CM of 410.x1 listed either as principal or secondary diagnosis before 1 st July (Kiyota et al. 2004) 5426 subjects Participants enrolled in the insurance plan throughout the study period with prescription drug coverage ( Medicare Part D) subjects Excluding patients with ESRD, disabilities and those that died within 30 days of discharge subjects Patients that initiated ACEI/ARB therapy within 90 days of discharge.

9 Variables & Analysis Plan Potential predictors of therapy discontinuation Demographic characteristics (Age, sex and race) Number of days in hospital (7, 7+ days) Comorbid conditions Concomitant medications Outcome Measure Time to discontinuation of therapy: Time to discontinuation of therapy was defined as the days from initiation of therapy to a gap of >90 days in therapy. Analysis Survival curves were modeled using the Kaplan-Meier technique, and potential predictors of therapy discontinuation were estimated using Cox proportional hazards regression.

10 RESULTS

11 Cumulative proportion of patients (%) Time to Discontinuation of ACEI/ARB Therapy 70% 60% 50% 40% 30% 20% 10% 0% Months from initiation to discontinuation of therapy

12 Factors Associated with Discontinuation Characteristics Cohort on ACEI/ARB Therapy (2039) Discontinuation N % Hazards Ratio [95% CI] P value Age yrs [0.809, 1.055] yrs Ref Sex Male [0.996, 1.304] Female Ref Race White [0.670, 0.985] Others [0.727, 1.296] Black Ref Number of days in hospital > 7 days [0.900, 1.176] days Ref

13 Factors Associated with Discontinuation Characteristics Cohort on ACEI/ARB Therapy (2039) Discontinuation N % Hazards Ratio [95% CI] P value Comorbid conditions Diabetes [0.898, 1.172] Dyslipidemia [0.596, 0.866] Congestive heart failure [1.012, 1.463] Cerebrovascular disease [1.011, 1.312] Peripheral vascular disease [0.946, 1.227] COPD [0.967, 1.253] Cancer [0.804, 1.106] Kidney disease [1.125, 1.464] Angina [0.871, 1.147] Coronary artery disease [0.801, 1.467] Concomitant medications Statins [0.698, 0.973] Beta-blockers [ 0.633, 0.950] Clopidogrel [0.885, 1.157]

14 Conclusions Only about half of MI patients continuously remained on ACEI/ARB therapy after 18 months of follow up. As far as demographic characteristics are concerned, blacks appeared to be at a higher risk of ACEI/ARB therapy discontinuation. Patients with certain comorbid conditions (congestive heart failure, cerebrovascular disease and kidney disease) were also found to be at a higher risk of therapy discontinuation. However, a co-diagnosis of dyslipidemia and concomitant treatment with statins and beta-blockers appeared to reduce the risk of therapy discontinuation. It is important that patients be provided adequate information and encouragement in order to improve adherence to ACEI/ARB therapy on an ongoing, long-term basis.

15 Limitations & Future Research Record of a medication being dispensed does not guarantee that the patient administered the drug. Side effects of ACEI therapy such as cough and increased potassium levels could have lead to therapy discontinuation. ICD-9-CM codes were used for identification of MI patients & additional comorbid conditions and therefore may have lead to miss-classification of subjects. Future research could follow patients for a longer period of time to find out if patients re-initiate therapy after a while. Further, time to a recurrent MI event post discontinuation of therapy could be studied. Our sample comprised of elderly patients, and hence a different dataset could be used to study a different population.

16 Funding The work reported was conducted as part of a project titled Using Medicare/Medicaid Claims Data to Support Medication Outcomes and Pharmacovigilance Research, which was supported by grant award 1COCMS330731/01 from the Office of Research, Development and Information, Centers for Medicare and Medicaid Services (CMS). The views expressed are those of the authors and do not necessarily reflect those of CMS or the University of Mississippi.

17 THANK YOU