Blood Pressure-Lowering Effects of Angiotensin Receptor Antagonist Monotherapy and in Combination with Other Anti-Hypertensive Drugs in Primary Care Settings in Japan

Management of Hypertension in the Asia-Pacific Region: A Structured Review

This article reviews available evidence regarding hypertension management in the Asia-Pacific region, focussing on five research questions that deal with specific aspects: blood pressure (BP) control, guideline recommendations, role of renin-angiotensin-aldosterone system (RAAS) inhibitors in clinical practice, pharmacological management and real-world adherence to guideline recommendations. A PubMed search identified 2537 articles, of which 94 were considered relevant. Compared with Europeans, Asians have higher systolic/diastolic/mean arterial BP, with a stronger association between BP and stroke. Calcium channel blockers are the most-commonly prescribed monotherapy in Asia, with significant variability between countries in the rates of angiotensin-converting enzyme inhibitors (ACEis)/angiotensin-receptor blockers (ARBs) and single-pill combination (SPC) use. In clinical practice, ARBs are used more commonly than ACEis, despite the absence of recommendation from guidelines and clinical evidence supporting the use of one class of drug over the other. Ideally, antihypertensive treatment should be tailored to the individual patient, but currently there are limited data on the characteristics of hypertension in Asia-Pacific individuals. Large outcome studies assessing RAAS inhibitor efficacy and safety in multi-national Asian populations are lacking. Among treated patients, BP control rates were ~ 35 to 40%; BP control in Asia-Pacific is suboptimal, and disproportionately so compared with Western nations. Strategies to improve the management of hypertension include wider access/availability of affordable treatments, particularly SPCs (which improve adherence), effective public health screening programs targeting patients to drive health-seeking behaviours, an increase in physician/patient awareness and early implementation of lifestyle changes. A unified Asia-Pacific guideline on hypertension management with pragmatic recommendations, particularly in resource-limited settings, is essential.

Antihypertensive effectiveness of combination therapy with losartan/hydrochlorothiazide for 'real world' management of isolated systolic hypertension

OBJECTIVES

The guidelines for hypertension require the presence of compelling indications for pharmacological management of hypertension associated with various diseases. Data mainly obtained through randomized controlled trials have provided evidence supporting effectiveness of the combination of losartan (Lo) and hydrochlorothiazide (HCTZ) for management of hypertensive patients. However, there have been few reports discussing the effectiveness of Lo/HTCZ (losartan 50 mg/hydrochlorothizide 12.5 mg) in the 'real world' in the management of isolated systolic hypertension (ISH). This study was designed to investigate the 'real world' effectiveness of Lo/HTCZ-based treatment of ISH associated with various diseases.

METHODS

This was a retrospective, uncontrolled analysis of data derived from a large, cross-sectional web-based clinical database collected by physicians.

RESULTS

Of 24,825 eligible patients, 20,726 were followed during a 6-month period. Among these, subjects for analysis included those with systolic blood pressure (SBP) >140 mmHg and diastolic BP (DBP) <90 mmHg; patients with diabetes mellitus and chronic kidney disease were excluded. A total of 15,846 patients were analysed. Among the various complications, hypercholesterolemia was the most frequent concomitant cardiovascular (CV) risk factor (48.1%), followed by obesity (16.3%). Associated clinical conditions were cerebrovascular diseases (9.6%), ischemic heart disease (7.9%) and left ventricular hypertrophy (4.6%). Total numbers of patients exhibiting any type of complications were 62% (≤64 years old), 69% (65-74 years old) and 67% (≥75 years old) (stratification of age). Mean SBP/DBP measurements (mm Hg) were 156/78 at the start, 140/72 at 1 month and 134/72 at 6 months. Blood pressure (BP) reductions associated with various diseases were similar among patients. Laboratory data including serum levels of total cholesterol, uric acid, hemoglobin A1c and serum potassium did not change during the study. Adverse effects such as orthostatic hypotension and considerable reductions in BP (>30 mmHg SBP) were rare.

CONCLUSIONS

Lo/HTCZ is safe and effective in reducing and improving BP control in a 'real world' setting. Treatment with Lo/HTCZ enabled a substantial proportion of hypertensive patients with associated diseases to achieve the recommended goal of <140 mm Hg.

Rationale, study design, baseline characteristics and blood pressure at 16 weeks in the HONEST Study

On the basis of the studies that investigated the relationship between baseline clinic blood pressure (CBP) or home blood pressure (HBP) values and cardiovascular (CV) events, HBP has been reported to have a stronger prognostic ability. However, few studies have compared the prognostic ability of on-treatment CBP and HBP. The relationship between on-treatment HBP, measured twice in the morning and twice at bedtime, and CV events was investigated in over 20 000 patients in the HONEST (Home blood pressure measurement with Olmesartan Naive patients to Establish Standard Target blood pressure) Study, a prospective, 2-year observational study of treatment with an angiotensin receptor blocker, olmesartan (OLM), in OLM-naive hypertensive patients. This report summarizes the study protocol, the baseline characteristics of the patients and CBP and HBP at 16 weeks. A total of 22 373 patients were registered across Japan; baseline data from 22 162 patients were collected. Baseline HBP (mean±s.d.) in the morning (the first measurement) was 151.6±16.4/87.1±11.8 mm Hg and at bedtime was 144.3±16.8/82.8±11.9 mm Hg, whereas CBP was 153.6±19.0/87.1±13.4 mm Hg. At 16 weeks, morning HBP was 135.0±13.7/78.8±9.9 mm Hg and bedtime HBP was 129.7±13.8/74.7±10.1 mm Hg, whereas CBP was 135.6±15.4/77.6±10.9 mm Hg. The follow-up period for each patient ends on 30 September 2012. The HONEST Study is expected to provide evidence showing the relationship between baseline and on-treatment CBP and HBP levels (both first and second measurements) and CV events.

Combination therapy with losartan/hydrochlorothiazide for blood pressure reduction and goal attainment in a real-world clinical setting in Japan

Objective:

When physicians prescribe a new antihypertensive drug, they do not know the extent of the drug’s effect on lowering blood pressure. To resolve this dilemma, a Web-based program was constructed for real-time entry and analysis of treatment. This observational study evaluated the efficacy of losartan/hydrochlorothiazide (Lo/HCTZ) in lowering blood pressure (BP) and achieving BP target values.

Methods:

Physicians prescribed Lo/HCTZ for patients with hypertension who failed to achieve target BP values of < 140/90 mmHg and < 130/80 mmHg in patients with diabetes or chronic kidney disease, respectively, with antihypertensive drugs including an angiotensin receptor blocker.

Results:

From December 2006 to December 2009, the data of 88,254 patients were entered into this database, and the data of 24,825 subjects were analyzed. At the first visit, a total of 88,254 patients received a first prescription of Lo/HCTZ daily. Among these, at the end of the present analysis, 24,825 (28%) outpatients had a follow-up visit at 1 month and 20,726 (23%) outpatients had a follow-up visit at 6 months. The prevalence of hypertensive patients achieving systolic blood pressure (SBP) control (< 140 mmHg) increased over time from 6.9% to 54.3% in females and 6.1% to 52.3% in males ( p < 0.05). At the start of the study, the levels of SBP were significantly highest in the eldest patients (≥ 75 years) followed by the group of 65–75 years and lowest in the youngest patients (≤ 64 years). However, at the end of the study, there were no differences in levels of SBP among the three groups.

Conclusions:

This Web-based system may provide useful information when a new drug is first released into the market. Treatment with Lo/HCTZ enabled a substantial proportion of hypertensive patients to achieve the recommended goal of < 140/90 mmHg.

Estimating antihypertensive effects of combination therapy in an observational study using marginal structural models

The evaluation of the antihypertensive effect of multiple antihypertensive drugs using data from an observational study requires adjustment for time-dependent confounders. Marginal structural models (MSMs) have been proposed to address this type of confounding through inverse probability weighting. Generally, the probabilities are estimated using logistic regression models that assume linearity between the logistic link and the predictors, but the linearity might be inaccurate. In this article, we proposed MSMs to assess the blood pressure-lowering effects of combination therapy with olmesartan medoxomil (OLM) plus calcium channel blockers (CCB) (OLM+CCB) in an observational study of OLM, and extended estimation methods of the probabilities for the MSMs using generalized additive models (GAMs). The estimation using GAMs was suggested to improve the balance of the distributions of confounder values between the therapy groups in the pseudo-population. We obtained estimated changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) for OLM+CCB combination therapy after 12 wk compared with OLM monotherapy of -4.3 mmHg (95% confidence interval (CI): -7.7 and -0.9 mmHg) and -2.9 mmHg (95% CI: -5.1 and -0.7 mmHg), respectively. The estimated target BP (SBP<140 mmHg and DBP<90 mmHg) achievement rates for OLM+CCB combination therapy and OLM monotherapy were 62.0 and 46.7%, respectively. The results of the MSMs were closer to those in the randomized controlled trial, such as the combination of OLM and amlodipine besylate in controlling high blood pressure study, than those of conventional methods. The proposed MSMs provided useful information to evaluate the effects of combination therapy of antihypertensive drugs in the context of an observational study.