Pharmacy & Therapeutics - November 2008 - (Page 652)

Medication Utilization Patterns and HypertensionRelated Expenditures among Patients Who Were Switched from Fixed-Dose To Free-Combination Antihypertensive Therapy Gregor y Hess, MD, MBA; Jerrold Hill, PhD; Helen Lau, MS; Homa Dastani, PhD; and Paresh Chaudhari, PharmD, MPH ABSTRACT Using a retrospective cohort study of medical and pharmacy claims data, we evaluated medication compliance, persistence, and hyper tension-related expenditures among patients who were switched from fixed-dose combination (FDC) to free-combination (FC) antihypertensive therapy. An example of a fixed-dose combination product for hypertension would be a valsartan/HCT tablet, and a free-combination product would be a valsartan tablet plus a diuretic tablet. The 7,224 patients identified from January 2003 to December 2005 were matched, in a 1:1 ratio, by propensity scores to controls who remained on their FC antihypertensive medications. Compliance, defined as a medication–possession ratio, was measured over 12 months. Persistence was measured as the percentage of patients who did not experience a lapse in therapy of more than 30 days since their last prescription refill. The patients continuing with FDC therapy had better persistence (42.5% higher; P < 0.002) and compliance (22.1% higher; P < 0.001), compared with patients who were switched to FC therapy. The 22.1% higher compliance rate for patients continuing the FDC regimen was associated with significantly lower expenditures for hypertension-related health care (P < 0.001) and an estimated 5% reduction in hypertensionrelated expenditures. Key words: fixed-dose combinations, antihypertensive therapies, health care costs, compliance, persistence INTRODUCTION More than 72 million adults in the U.S. have hypertension, Dr. Hess is Vice President and Chief Medical Officer at SDI in Plymouth Meeting, Pennsylvania; a Senior Fellow at the Leonard Davis Institute for Health Economics and Policy at the University of Pennsylvania in Philadelphia; and a Senior Scholar in the Department of Health Policy at Jefferson Medical College, Thomas Jef ferson University, in Philadelphia. Dr. Hill is Director of Outcomes Research at SDI. Ms. Lau is Associate Director and Dr. Dastani is Assistant Director, both in Health Economics and Outcomes Research at Novartis Pharmaceuticals Corporation in East Hanover, New Jersey. Dr. Chaudhari is a Fellow at Jefferson’s Department of Health Policy in Philadelphia. making it the most common cardiovascular disease.1 If hypertension is not properly managed, it can lead to serious adverse cardiovascular and cerebrovascular events, including myocardial infarction (MI), angina pectoris, stroke, and renal disease.2 Although lifestyle and diet modifications have the potential to decrease the incidence of hypertension in the general population and improve patients’ blood pressure (BP) control rates, many patients require pharmacological intervention to maintain control of BP.3–5 Medications commonly prescribed for hypertension include thiazide-type diuretics such as hydrochlorothiazide (HCTZ), angiotensin-receptor blockers (ARBs), angiotensin-converting enzyme (ACE)–inhibitors, and calcium-channel blockers. These medications are either prescribed as monotherapy (one agent taken as a single tablet or capsule) or as combination therapy (multiple agents taken as a daily regimen of multiple tablets or as a single tablet in a fixed-dose combination (FDC) agent. The evidence suggests that most patients with hypertension require combination therapy to reach target BP.2,6–10 For example, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) states that most patients need two or more drugs to achieve BP control.2 Although free-combination (FC) medications are chemically equivalent to FDC products, FC regimens increase the complexity of using and acquiring medications. Simpler regimens can improve medication persistence and compliance for different diseases and age groups.11–15 Studies specifically comparing single-tablet FDC and FC antihypertensive regimens have demonstrated better persistence and compliance with FDC therapies.16–19 One study that compared FDC lisinopril/hydrochlorothiazide (HCTZ) with FC lisinopril plus a diuretic, and FDC enalapril/HCTZ versus FC enalapril plus a diuretic, showed a 21.7% and an 18.8% improvement, respectively, in persistence in the FDC arm after 12 months.20 Another study examined medication compliance, use of health care resources, and costs in FDC amlodipine besylate/benazepril HCl therapy and a comparable FC componentbased therapy.17 The study demonstrated a 7% absolute increase in the compliance rate in the FDC group. The total Disclosure: Dr. Hess and Dr. Hill have received research support from Novartis. Ms. Lau and Dr. Dastani are employees of Novartis. Dr. Chaudhari has received research support from Surveillance Data, Inc. Accepted for publication August 25, 2008 652 P&T® • November 2008 • Vol. 33 No. 11

Table of Contents Feed for the Digital Edition of Pharmacy & Therapeutics - November 2008

Pharmacy & Therapeutics - November 2008 Contents Editorial Medication Errors Prescription: Washington New Drugs/Drug News/New Medical Devices Drug Forecast Heparin-Induced Thrombocytopenia Medication Utilization Patterns and Hypertension-Related Expenditures among Patients Who Were Switched From Fixed-Dose to Free-Combination Antihypertensive Therapy European Society for Medical Oncology and Association for the Study of Bone and Mineral Research Pharmaceutical Approval Update

Pharmacy & Therapeutics - November 2008

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