Pharmacy & Therapeutics - November 2008 - (Page 662)

Switching from Fixed-Dose to Free-Combination Antihypertensive Medications Table 4 Effect of Higher Increase in Compliance on Hypertension-Related Utilization and Costs* Effect of a 10-Percentage Point Increase in Compliance (Medication–Possession Ratio) Total Utilization and Expenditures Percent with hypertension-related inpatient service Percent with hypertension-related emergency department visit Percent with hypertension-related office visit Total hypertension-related expenditures (services only) Total hypertension-related expenditures (services and prescriptions) Effect –0.3% (–0.4%, –0.2%)† –0.2% (–0.2%, –0.1%) –0.4 (–0.7%, –0.1%)% –$60 (–$64, –$58) –$33 (–$40, –$26) P Value 0.001 0.001 0.003 0.001 0.001 Commercial Effect –0.2% (–0.4%, –0.2%) –0.2% (–0.3%, –0.1%) –0.6% (–1%, –0.2%) –$53 (–$56, –$50) –$25 (–$33, –$17) P Value 0.001 0.001 0.001 0.001 0.001 Medicare Effect –0.3% (–0.5%, –0.2%) –0.1% (–0.2%, 0.0%) –0.2% (–0.6%, 0.2%) –$70 (–$75, –$65) –$48 (–$61, –$36) P Value 0.001 0.004 0.337 0.001 0.001 * Effect size derived from marginal effects of generalized linear models, controlling for cohort, age, sex, comorbidities, and health care expenditures six months prior to the index date. † Numbers in parentheses are 95% confidence intervals. DISCUSSION Persistence and compliance were significantly higher for patients continuing with fixed-dose combination (FDC) therapy, compared with patients who switched from FDC therapy to free-combination (FC) therapy. This finding supports the hypothesis that simplifying antihypertensive drug regimens may improve persistence and compliance. The results are consistent with a meta-analysis by Bangalore et al., which showed a reduction of 24% in noncompliance when FDC regimens were prescribed instead of FC for treating hypertension.19 Simplifying medication regimens is particularly important, because most patients need more than one antihypertensive agent to reach their BP goal.2,6–10 Patients’ use of and expenses for hypertension-related services decreased as medication compliance increased. Total expenditures for hypertension-related services and medications also decreased as compliance increased, suggesting that the reductions in expenditures for hypertension-related services were greater than the increased medication expenditures associated with higher compliance. Uncontrolled BP significantly increases the risk of adverse cardiovascular outcomes such as MI, stroke, and mortality.37 Previous studies have demonstrated that improved compliance with antihypertensive medications is associated with improved BP control21–24 and lower health care costs.25,27,28,34,37 Our results showed higher compliance with FDC medications and reduced utilization and costs, attributed to improved compliance; these findings suggest that FDC regimens, when compared with FC regimens, are likely to produce positive health benefits through better control of hypertension and positive economic benefits through lower utilization and expenditures for hypertension-related health care. Notable are the estimated reductions for FDC, compared with FC, of 21.3% in hypertension-related hospitalizations, 20.2% in expenditures for hypertension-related services, and 5.1% in expenditures for hypertension-related services and medications combined. The relative economic benefits of FDC regimens are likely to extend beyond hypertension-related health care, because improved BP control reduces the incidence and severity of other costly diagnoses such as congestive heart failure, stroke, and renal disease.1,46,47 Thus, estimated reductions in the use of health care resources and costs derived from this study may be conservative estimates of potential impact of FDC regimens on total health care utilization and costs over time. Our findings and the growing volume of published literature suggest that clinical and formulary design decisions should focus on the complexity of drug regimens and their potential impact on persistence and compliance behaviors of patients, in addition to the costs of medications. Changes based solely on medication costs can have deleterious effects on compliance and patient outcomes. STUDY LIMITATIONS The study was limited in several ways. The severity of hypertension could not be assessed and treatment cohorts were nonrandomized groups, thus limiting the internal validity of the study. Persistence and compliance were also measured from medication refill patterns observed within pharmacy claims data and were not based on observations of patients taking their medications. Because most patients incur an out-of-pocket cost for refilling a medication with a copayment and with a timecost for filling the prescription, purchases are more likely to correspond with actual use, making medication fill rates an accepted measure of persistence and compliance.48–52 Our study did not measure the overall complexity of patients’ drug regimens, the presumed reason for lower compliance and persistence in the FC cohort. Thus, we did not continued on page 665 662 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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