Abstract 11907: Choice of Antihypertensive Combination Therapy Based on Daily Salt Intake

Abstract

Introduction: To achieve strict blood pressure control, combination therapy with multiple antihypertensive agents, including angiotensin receptor blockers (ARBs) are recommended. Recently, various ARB combination pills have been developed, including ARBs combined with thiazide diuretics (TZs) and calcium channel blockers (CCBs). However, it has yet to be determined which drug class, the TZs or the CCBs, is more efficacious as add-on therapy to ARBs in controlling hypertension. Hypothesis: This study was designed to test our hypothesis that the combination treatment with ARB/TZ would be better in hypertensive patients with high salt diet intake to lower blood pressure, compared to that with ARB/CCB. Methods: Hypertensive patients who failed to reach blood pressure goals despite treatment with ARBs alone were randomly assigned to receive either ARB/TZ or ARB/CCB combination therapy. Estimated daily sodium intake was calculated from spot urine values of sodium and creatinine. Blood pressure was measured at baseline, and at 4, 8 and 12 weeks after starting combination therapy. Results: For all study patients (n=87), diastolic blood pressure (DBP) reduction was greater in 49 patients receiving ARB/CCB treatment, compared to 38 patients receiving ARB/TZ treatment (11±10 vs. 6±12 mmHg, P<0.05 at 4 weeks; 12±11 vs. 5±11 mmHg, P<0.05 at 8 weeks; 13±11 vs. 7±9 mmHg, P<0.05 at 12 weeks, respectively), although the magnitude of the SBP reduction was similar in each group. In the 37 patients with a baseline estimated daily salt intake greater than 10 g and baseline systolic blood pressure (SBP) ranging from 150 to 200 mmHg, SBP was lower (130±12 vs. 141±17 mmHg , P<0.05) and SBP reduction was greater (35±17 vs. 24±17 mmHg , P<0.05) at 4 weeks in patients receiving ARB/TZ treatment, compared to patients receiving ARB/CCB treatment. In the 31 patients whose estimated daily salt intake increased at 12 weeks compared to baseline, SBP at 12 weeks was lower in patients receiving ARB/TZ treatment, compared to patients receiving ARB/CCB treatment (131±8 vs. 139±10 mmHg, P<0.05). Conclusion: Estimated daily salt intake is a useful tool for guiding antihypertensive therapy and should be measured repeatedly during the therapeutic course.