Abstract
Combination therapy using two or three classes of drugs is often required to treat hypertension to prevent cardiovascular disease. In this study, we examined combination therapies administered following initial therapy with an angiotensin II receptor blocker (ARB) in hypertensive Japanese patients. To determine which classes of antihypertensives are being prescribed as second- or third-line treatments for patients who were initially treated with a single ARB, we analyzed prescription claims data from two Japanese health-care databases for 2008 to 2015. Among the 26 998 patients who were initially treated with a single ARB (from one database), calcium channel blockers (CCBs) were the most frequently prescribed second-line antihypertensive, as these medicines were added for >20% of patients within 1 year of ARB prescription initiation. The addition rates of CCBs as a second-line therapy differed depending on the initial ARB type. In contrast, <10% of patients received a diuretic as a second-line antihypertensive. Among the 48 813 patients who were prescribed an ARB in combination with a CCB (as shown in the other database), diuretics were prescribed as third-line antihypertensives more frequently than increased doses of CCBs or ARBs. Diuretics were added for 8% of patients within 2 years of CCB addition, and the addition rates differed based on the CCB dose used for combination therapy. We also found that the addition rates of diuretics differed depending on patient clinical histories among ARB and CCB recipients.