A Retrospective Study of Persistence with Single-pill Combination Therapy Vs. Concurrent Two-pill Therapy in Patients with Hypertension

Context: Patients with hypertension often fail to control their blood pressure because they do not comply with pharmacologic therapy. It was hypothesized that a greater percentage of patients receiving a single pill combining an ACE inhibitor and a diuretic would persist with therapy than patients receiving both drugs as separate pills.

Methods: Prescription data were obtained from a large commercial pharmacy benefit manager (PBM). The records of presumably newly diagnosed hypertensive patients for whom lisinopril combined with hydrochlorothiazide in a single pill (lisinopril/HCTZ) was prescribed (n = 1,644) were compared with those of patients for whom lisinopril and a diuretic were prescribed concurrently (n = 624). Likewise, the records of patients for whom enalapril maleate combined with hydrochlorothiazide in a single pill (enalapril/HCTZ) was prescribed (n = 969) were compared with those of patients for whom enalapril maleate and a diuretic were prescribed concurrently (n = 705). Patients were regarded as persisting if they renewed their prescription within three times the number of days supplied by the previous prescription. Patients were followed for one year from the date of the initial prescription.

Results: At 12 months, the percentages of patients persisting with lisinopril/HCTZ (68.7 percent) and enalapril/HCTZ (70.0 percent) therapy were 18.8 percent and 21.7 percent greater, respectively, than the percentages of patients persisting with lisinopril plus concurrent diuretic therapy (57.8 percent) or enalapril maleate plus concurrent diuretic therapy (57.5 percent). Statistical significance (p < 0.05) was demonstrated at 6 and 12 months for both comparisons.

Conclusion: The simplification of a drug regimen by using combination therapy in a single pill for hypertension resulted in significant increases in persistence with prescribed therapy.