Predicting age- and dose-related responses to antihypertensive therapy: pooled analysis of two randomized clinical trials of valsartan alone and combined with hydrochlorothiazide

Efficacy, safety, and tolerability of valsartan/hydrochlorothiazide in Asian patients with essential hypertension

INTRODUCTION

Previous studies have demonstrated that hypertensive patients need concomitant therapy with one or more drugs from different classes of antihypertensive agents to achieve their blood pressure control targets. We performed the first multinational observational study of valsartan/hydrochlorothiazide (HCTZ) single pill combination in Asia to determine the efficacy, safety, and tolerability in hypertensive patients. The objective of this multinational, multicenter, 24-week follow-up observational study is to evaluate the efficacy, safety, and tolerability of valsartan/hydrochlorothiazide single pill combination in the treatment of essential hypertension in the Asia-Pacific region.

METHODS

A total of 7567 Asian patients who were diagnosed with stage 1 or stage 2 essential hypertension and who took at least one dose of valsartan/hydrochlorothiazide single pill combination were included in the statistical analyses. A total of 59% were taking antihypertensive medication at the time of the study. Eligible patients received valsartan/hydrochlorothiazide single pill combination 80/12.5 mg tablets orally once daily at visit 1. The investigator could decide the subsequent dose of valsartan/hydrochlorothiazide single pill combination for their patients, and efficacy, safety, and tolerability data were collected at week 4, 12, and 24.

RESULTS

Basal blood pressure was 155.9±13.3 mmHg (systolic) and 96.3±10.1 mmHg (diastolic). Response rates and control rates increased continuously from baseline to the study endpoint at week 24, when they reached 94.6% and 73.2%, respectively. Systolic and diastolic blood pressure reductions were -25.4±15.2 mmHg and -14.9±13.5 mmHg, respectively (P<0.001). Using a four-point global assessment scale, 96.8% of the patients and physicians reported good, very good, or excellent for both their subjective efficacy and tolerability assessments.

CONCLUSION

In this multicenter, multicountry study including 7567 Asian patients with hypertension, valsartan/hydrochlorothiazide single pill combination was found efficacious, well tolerated, and devoid of any serious adverse effects.

Valsartan: more than a decade of experience

Valsartan is a nonpeptide angiotensin receptor antagonist that selectively blocks the binding of angiotensin II to the angiotensin II type 1 receptor. The efficacy, tolerability and safety of valsartan have been demonstrated in large-scale studies in hypertension, heart failure (HF) and post-myocardial infarction (MI). This review focuses on what was learned from the valsartan clinical research programme and other comparative trials published from 1997 to the present. Many studies have demonstrated the efficacy of valsartan in lowering blood pressure (BP) in a variety of patient populations (including elderly, women, children, obese patients, patients with diabetes mellitus, patients with chronic kidney disease [CKD], patients at high risk of cardiovascular [CV] disease, African Americans, Hispanic Americans and Asians) and in improving outcomes in CV disease and CKD. In hypertension, valsartan exhibits dose-dependent efficacy in reducing both systolic and diastolic BP over the once-daily dose range of 80-320 mg; doses as high as 640 mg/day have been studied and found to be efficacious and safe. BP control can be enhanced with a more consistent 24-hour BP-lowering profile by using single-pill, fixed-dose combination therapy with valsartan plus hydrochlorothiazide (HCTZ). The cardioprotective benefits of valsartan have been demonstrated in large-scale outcome trials and include significant reductions in CV morbidity and mortality in HF, following MI, and in patients with co-morbid hypertension and coronary artery disease and/or HF; reductions in HF hospitalizations; and reductions in the incidence of stroke. The magnitude of these effects is comparable with that demonstrated with angiotensin-converting enzyme (ACE) inhibitors; however, valsartan has a more favourable tolerability profile, with a significantly lower incidence of cough and only rare reports of angio-oedema, both class effects of ACE inhibitor use. Consistent with its angiotensin receptor-blocking effects, valsartan also reduces circulating levels of biochemical markers that are associated with angiotensin II-mediated endothelial dysfunction and CV risk (e.g. high-sensitivity C-reactive protein or oxidized low-density lipoprotein). Improvements in CKD with valsartan include statistically and clinically meaningful reductions in urinary albumin and protein excretion in patients with type 2 diabetes and in nondiabetic patients with CKD. In short-term studies, valsartan has improved or stabilized various indices of metabolic function in at-risk patients, including those with co-morbid hypertension, obesity and/or metabolic syndrome. Because of this, valsartan is being prospectively investigated for its ability to reduce the incidence of new-onset diabetes and provide cardioprotection in patients with impaired glucose tolerance. Valsartan and valsartan/HCTZ are well tolerated. In clinical trials, adverse events during valsartan treatment were similar to those occurring with placebo. The combination of valsartan/HCTZ was better tolerated than HCTZ alone. Valsartan is administered once daily for hypertension; doses are usually taken upon awakening. In patients with HF or MI, valsartan is administered twice daily.