Combination antihypertensive therapy with an angiotensin receptor blocker (ARB) and a calcium channel blocker (CCB) or diuretics is common. This subanalysis investigated the influential factor on blood pressure (BP) variability in patients receiving ARB-based combination therapy.Design and Method:
In a prospective, randomized, open-label trial, hypertensive outpatients (>65 years) who did not achieve their target BP with ARB monotherapy switched to losartan 50 mg/hydrochlorothiazide 12.5 mg (ARB + D, n = 72) or ARB plus amlodipine 5 mg (ARB + C, n = 68) for 12 months. Clinic BP measured every 3 months, visit-to-visit variability and seasonal variation were evaluated.Results:
No significant between-group differences in average, maximum, or minimum systolic BP (SBP) or diastolic BP (DBP) were found (ARB + D: 133/74 ± 11/8 mmHg, 145/80 ± 14/9 mmHg, 121/67 ± 12/10 mmHg, vs. ARB + C: 133/73 ± 11/8 mmHg, 142/79 ± 13/10 mmHg, 122/66 ± 11/9 mmHg). However, the (maximum – minimum) SBP was significantly higher in the ARB + D group than in the ARB + C group. The visit-to-visit variability assessed by the standard deviation (SD) -SBP and coefficient of variation (CV)-SBP were significantly higher in the ARB + D group than ARB + C group (ARB + D: 9.7 ± 4.4, 7.3 ± 3.2, ARB + C: 8.1 ± 3.6, 6.1 ± 2.6). When each group was subdivided into two seasonal groups (summer and winter), no significant between-group differences in BP were found. The multivariate regression analyses showed that the significant determinants for both SBP-SD at 12 months and SBP-CV at 12 months were age and ARB/HCTZ combination.Conclusions:
In conclusion, combination therapy with an ARB plus a CCB may be preferable to that with an ARB plus diuretics for decreasing BP variability. Diuretics were the most influential factor on the BP variability in our ARB-based combination therapy.