Pharmacy & Therapeutics - November 2008 - (Page 661)

Switching from Fixed-Dose to Free-Combination Antihypertensive Medications Table 2 Persistence and Compliance over the 12-Month Study Period with Fixed-Dose Combination (FDC) and Free-Combination (FC) Regimens Regression-Adjusted Differences: FDC vs. FC§† FDC–FC† 46.8% Total Commercial Medicare Unadjusted Rates Total Sample FDC Persistence at month 12* Compliance at month 12‡ 58.3% FC 14.9% FDC–FC† 43.4% FDC 56.2% Commercial FC 15.2% FDC–FC† 41.0% FDC 61.2% Medicare FC 14.4% 42.5% (40.6%– 44.5%)¶ 40.4% (37.8%– 43.0%) 45.2% (42.2%– 48.2%) 76.9% 54.4% 22.5% 74.9% 55.4% 19.5% 79.4% 52.9% 26.5% 22.1% (19.9%– 24.1) 19.3% (16.5%– 22.0%) 25.0% (21.5%– 28.1%) * Patient must remain on therapy through the month to be considered persistent at that month. Patients are classified as non-persistent if they have a lapse in therapy more than 30 days from the date of the last available day of medication supply from one prescription to the refill date for the next prescription. † P values less than 0.001 for the FDC–FC difference in rates. ‡ Compliance is measured by the medication–possession ratio (MPR), the percent of the study follow-up period (365 days) for which the patient has a supply of the medication (MPR = [days supply] divided by 365 x100). Days supply is obtained from prescription drug claims data. § Regression-adjusted differences were derived from marginal effects of generalized linear models, controlling for cohort, age, sex, comorbidities, and health care expenditures six months prior to index date. ¶ Numbers in parentheses are 95% confidence intervals. Table 3 Unadjusted Hypertension-Related Health Care Utilization and Costs for Patients Receiving Fixed-Dose Combination (FDC) and Free-Combination (FC) Antihypertensive Medications Total FC n =7,225 FDC n = 7,224 P Value 0.016 0.001 0.001 0.012 0.001 Commercial FC n = 4,109 2.14% 1.48% 65.54% FDC n = 4,108 1.36% 0.80% 58.01% P Value* 0.007 0.004 0.001 0.002 0.001 Medicare FC n = 3,116 4.40% 2.02% 66.17% FDC P n = 3,116 Value 3.88% 0.83% 61.20% 0.303 0.001 0.001 0.683 0.246 Percent with hypertension-related 3.11% 2.45% inpatient service Percent with hypertension-related 1.72% 0.82% emergency department visit Percent with hypertension-related 65.81% 59.39% office visit Hypertension-related expenditures $657.18 $468.94 for services ($4,976.36)† ($4,013.98) Hypertension-related expenditures $1,423.99 $1,138.91 for services and prescriptions ($5,040.68) ($4,062.68) $625.44 $331.80 ($5,202.00) ($3,229.74) $1,343.64 $949.62 ($5,268.22) ($3,282.15) $699.03 $649.74 ($4,662.63) ($4,852.80) $1,529.95 $1,388.47 ($4,722.64) ($4,894.86) * P values are for chi-square tests on FC–FDC differences in percent using a service and for t-tests on FC–FDC differences in mean expenditures. † Standard deviations for expenditures are in parentheses. the total number of FDC patients was 22.1 percentage points higher than the total number of FC patients (see Table 2 for regression-adjusted differences), the estimated percentage of total FDC patients hospitalized for hypertension was 0.44% less than the percentage for the total number of FC patients (i.e., –0.03% × 22.1% = –0.66%). This figure represents a 21.3% reduction in the number of FDC patients hospitalized for hypertension, compared with FC patients (based on the 3.11% of the total number of FC patients hospitalized). When we used the same methodology, the higher compliance for total FDC patients was associated with a 25.7% annual reduction in the number of patients needing emergency visits for hypertension and a 1.3% annual reduction in the number of patients making physician visits for hypertension, compared with the total for FC. Similarly, higher compliance for total FDC patients was associated with a $133 reduction (20%) in annual expenditures for hypertension-related services, and a $73 reduction (5%) in total hypertension-related health care (ser vices and medications). Commercial and Medicare patients experienced similar patterns of lower utilization and expenditures, as reported previously, for the total patient sample except for Medicare office visits. Vol. 33 No. 11 • November 2008 • P&T® 661

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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