Comparison of therapy persistence for fixed versus free combination antihypertensives: a retrospective cohort study

ObjectivesThe aim of the study was to compare therapy persistence among patients who started with one of three drug regimens: a monotherapy, or combination therapy either as a fixed combination (ie, ‘single pill’) or as a free combination (ie, two separate antihypertensive agents).DesignIn a secondary data analysis, we used descriptive statistics and multivariate logistic regression to measure the effect of the three therapy regimens on therapy persistence over 4 years.SettingPrescription data from a large German statutory health insurance provider.ParticipantsAll patients who started with a new antihypertensive therapy in 2007 or 2008 (n=8032) were included and followed for 4 years.Primary outcome measureTherapy persistence, defined as receiving a refill prescription no later than within 180 days.ResultsThe persistence rates after 4 years were nearly identical among patients who started with a monotherapy (40.3%) or a fixed combination of two drugs (39.8%). However, significantly more patients who started with free-drug combinations remained therapy persistent (56.4%), resulting in an OR of 2.00 (95% CI 1.6 to 2.5; p