Blood pressure lowering efficacy of potassium-sparing diuretics (that block the epithelial sodium channel) for primary hypertension

First-line diuretics versus other classes of antihypertensive drugs for hypertension

BACKGROUND

Different first-line drug classes for patients with hypertension are often assumed to have similar effectiveness with respect to reducing mortality and morbidity outcomes, and lowering blood pressure. First-line low-dose thiazide diuretics have been previously shown to have the best mortality and morbidity evidence when compared with placebo or no treatment. Head-to-head comparisons of thiazides with other blood pressure-lowering drug classes would demonstrate whether there are important differences.

OBJECTIVES

To compare the effects of first-line diuretic drugs with other individual first-line classes of antihypertensive drugs on mortality, morbidity, and withdrawals due to adverse effects in patients with hypertension. Secondary objectives included assessments of the need for added drugs, drug switching, and blood pressure-lowering.

SEARCH METHODS

Cochrane Hypertension's Information Specialist searched the Cochrane Hypertension Specialized Register, CENTRAL, MEDLINE, Embase, and trials registers to March 2021. We also checked references and contacted study authors to identify additional studies. A top-up search of the Specialized Register was carried out in June 2022.

SELECTION CRITERIA

Randomized active comparator trials of at least one year's duration were included. Trials had a clearly defined intervention arm of a first-line diuretic (thiazide, thiazide-like, or loop diuretic) compared to another first-line drug class: beta-blockers, calcium channel blockers, alpha adrenergic blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, direct renin inhibitors, or other antihypertensive drug classes. Studies had to include clearly defined mortality and morbidity outcomes (serious adverse events, total cardiovascular events, stroke, coronary heart disease (CHD), congestive heart failure, and withdrawals due to adverse effects).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 20 trials with 26 comparator arms randomizing over 90,000 participants. The findings are relevant to first-line use of drug classes in older male and female hypertensive patients (aged 50 to 75) with multiple co-morbidities, including type 2 diabetes. First-line thiazide and thiazide-like diuretics were compared with beta-blockers (six trials), calcium channel blockers (eight trials), ACE inhibitors (five trials), and alpha-adrenergic blockers (three trials); other comparators included angiotensin II receptor blockers, aliskiren (a direct renin inhibitor), and clonidine (a centrally acting drug). Only three studies reported data for total serious adverse events: two studies compared diuretics with calcium channel blockers and one with a direct renin inhibitor. Compared to first-line beta-blockers, first-line thiazides probably result in little to no difference in total mortality (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.84 to 1.10; 5 trials, 18,241 participants; moderate-certainty), probably reduce total cardiovascular events (5.4% versus 4.8%; RR 0.88, 95% CI 0.78 to 1.00; 4 trials, 18,135 participants; absolute risk reduction (ARR) 0.6%, moderate-certainty), may result in little to no difference in stroke (RR 0.85, 95% CI 0.66 to 1.09; 4 trials, 18,135 participants; low-certainty), CHD (RR 0.91, 95% CI 0.78 to 1.07; 4 trials, 18,135 participants; low-certainty), or heart failure (RR 0.69, 95% CI 0.40 to 1.19; 1 trial, 6569 participants; low-certainty), and probably reduce withdrawals due to adverse effects (10.1% versus 7.9%; RR 0.78, 95% CI 0.71 to 0.85; 5 trials, 18,501 participants; ARR 2.2%; moderate-certainty). Compared to first-line calcium channel blockers, first-line thiazides probably result in little to no difference in total mortality (RR 1.02, 95% CI 0.96 to 1.08; 7 trials, 35,417 participants; moderate-certainty), may result in little to no difference in serious adverse events (RR 1.09, 95% CI 0.97 to 1.24; 2 trials, 7204 participants; low-certainty), probably reduce total cardiovascular events (14.3% versus 13.3%; RR 0.93, 95% CI 0.89 to 0.98; 6 trials, 35,217 participants; ARR 1.0%; moderate-certainty), probably result in little to no difference in stroke (RR 1.06, 95% CI 0.95 to 1.18; 6 trials, 35,217 participants; moderate-certainty) or CHD (RR 1.00, 95% CI 0.93 to 1.08; 6 trials, 35,217 participants; moderate-certainty), probably reduce heart failure (4.4% versus 3.2%; RR 0.74, 95% CI 0.66 to 0.82; 6 trials, 35,217 participants; ARR 1.2%; moderate-certainty), and may reduce withdrawals due to adverse effects (7.6% versus 6.2%; RR 0.81, 95% CI 0.75 to 0.88; 7 trials, 33,908 participants; ARR 1.4%; low-certainty). Compared to first-line ACE inhibitors, first-line thiazides probably result in little to no difference in total mortality (RR 1.00, 95% CI 0.95 to 1.07; 3 trials, 30,961 participants; moderate-certainty), may result in little to no difference in total cardiovascular events (RR 0.97, 95% CI 0.92 to 1.02; 3 trials, 30,900 participants; low-certainty), probably reduce stroke slightly (4.7% versus 4.1%; RR 0.89, 95% CI 0.80 to 0.99; 3 trials, 30,900 participants; ARR 0.6%; moderate-certainty), probably result in little to no difference in CHD (RR 1.03, 95% CI 0.96 to 1.12; 3 trials, 30,900 participants; moderate-certainty) or heart failure (RR 0.94, 95% CI 0.84 to 1.04; 2 trials, 30,392 participants; moderate-certainty), and probably reduce withdrawals due to adverse effects (3.9% versus 2.9%; RR 0.73, 95% CI 0.64 to 0.84; 3 trials, 25,254 participants; ARR 1.0%; moderate-certainty). Compared to first-line alpha-blockers, first-line thiazides probably result in little to no difference in total mortality (RR 0.98, 95% CI 0.88 to 1.09; 1 trial, 24,316 participants; moderate-certainty), probably reduce total cardiovascular events (12.1% versus 9.0%; RR 0.74, 95% CI 0.69 to 0.80; 2 trials, 24,396 participants; ARR 3.1%; moderate-certainty) and stroke (2.7% versus 2.3%; RR 0.86, 95% CI 0.73 to 1.01; 2 trials, 24,396 participants; ARR 0.4%; moderate-certainty), may result in little to no difference in CHD (RR 0.98, 95% CI 0.86 to 1.11; 2 trials, 24,396 participants; low-certainty), probably reduce heart failure (5.4% versus 2.8%; RR 0.51, 95% CI 0.45 to 0.58; 1 trial, 24,316 participants; ARR 2.6%; moderate-certainty), and may reduce withdrawals due to adverse effects (1.3% versus 0.9%; RR 0.70, 95% CI 0.54 to 0.89; 3 trials, 24,772 participants; ARR 0.4%; low-certainty). For the other drug classes, data were insufficient. No antihypertensive drug class demonstrated any clinically important advantages over first-line thiazides.

AUTHORS' CONCLUSIONS

When used as first-line agents for the treatment of hypertension, thiazides and thiazide-like drugs likely do not change total mortality and likely decrease some morbidity outcomes such as cardiovascular events and withdrawals due to adverse effects, when compared to beta-blockers, calcium channel blockers, ACE inhibitors, and alpha-blockers.

Blood pressure lowering effect of hydrochlorothiazide compared to other diuretics for hypertension

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

This review aims to assess the short‐term (3 to 12 weeks) blood pressure lowering efficacy of hydrochlorothiazide in comparison with other diuretics for primary hypertension in adults, and will build upon the other Cochrane Reviews studying the blood pressure lowering effect of diuretics (Chen 2009; Musini 2009; Musini 2014). The main outcomes of this review will be change in blood pressure, heart rate, and withdrawals due to adverse effects three to 12 weeks after starting the medication.

Thiazide diuretics alone or in combination with a potassium-sparing diuretic on blood pressure-lowering in patients with primary hypertension: protocol for a systematic review and network meta-analysis

BACKGROUND

The use of thiazide (T) diuretics for the treatment of hypertension may be associated with adverse metabolic effects, which can be minimized by combining thiazides with potassium-sparing (PS) diuretics. The additional blood pressure (BP)-lowering effect provided by the addition of a PS diuretic is unclear. Due to a large number of drugs in the T diuretics class, and the possible difference between them, there is a need to identify the best available evidence for health decision-making. This systematic review with network meta-analysis aims to compare the antihypertensive efficacy of T diuretics alone or in combination with a PS diuretic in patients with primary hypertension, as well as the safety of such drugs through the measurement of drug-related adverse events.

METHODS

A comprehensive electronic search will be conducted in six electronic bibliographic databases (PubMed/MEDLINE, Cochrane Library, Embase, Web of Science, Scopus, Lilacs), a registration database ( ClinicalTrials.gov ), and Educational Resources Information Center (ERIC [ProQuest]), published from inception to the date of the search. The search will be updated towards the end of the review. A hand search of the reference sections of the included studies and cited studies will also be performed. In case of missing data, authors will be contacted by e-mail or academic social networking sites whenever possible. To be included in the review, studies must be double-blind randomized controlled trials evaluating T diuretics alone or in combination with PS diuretics in patients with primary hypertension. The primary outcome measure will be office BP. Ambulatory BP monitoring (ABPM), non-melanoma skin cancer, major adverse cardiovascular events, laboratory parameters, and the number of withdrawals will be included as secondary outcomes. The results will be quantitatively summarized using differences between the mean change from baseline or differences between means for quantitative outcomes and relative risk for dichotomous outcomes. Results will be presented as mean or relative risk with credible intervals through a league table. The treatments will also be ranked using the surface under the cumulative ranking curve method. The risk of bias will be assessed through the RoB 1.0 tool.

DISCUSSION

To the best of our knowledge, this review will be the first to synthesize currently available evidence on the antihypertensive efficacy of different T diuretics alone or in combination with PS diuretics in adults with hypertension. The goals of hypertension treatment are to control high BP and to reduce associated cardiovascular morbidity and mortality, using the most appropriate therapy. Thiazides are widely used for pharmacological treatment due to their demonstrated effectiveness in reducing BP, favorable safety profile, and low cost. The results of this study will provide evidence regarding the best therapeutic strategies with T and PS diuretics, evidencing interventions with better antihypertensive efficacy and safety profile.

TRIAL REGISTRATION

This systematic review and network meta-analysis was prospectively registered at the PROSPERO database ( CRD42018118492 ).

Epithelial Sodium Channel and Salt-Sensitive Hypertension

The development of high blood pressure is influenced by genetic and environmental factors, with high salt intake being a known environmental contributor. Humans display a spectrum of sodium-sensitivity, with some individuals displaying a significant blood pressure rise in response to increased sodium intake while others experience almost no change. These differences are, in part, attributable to genetic variation in pathways involved in sodium handling and excretion. ENaC (epithelial sodium channel) is one of the key transporters responsible for the reabsorption of sodium in the distal nephron. This channel has an important role in the regulation of extracellular fluid volume and consequently blood pressure. Herein, we review the role of ENaC in the development of salt-sensitive hypertension, and present mechanistic insights into the regulation of ENaC activity and how it may accelerate sodium-induced damage and dysfunction. We discuss the traditional role of ENaC in renal sodium reabsorption and review work addressing ENaC expression and function in the brain, vasculature, and immune cells, and how this has expanded the implications for its role in the initiation and progression of salt-sensitive hypertension.

First-line combination therapy versus first-line monotherapy for primary hypertension

BACKGROUND

This is the first update of a review originally published in 2017. Starting with one drug and starting with a combination of two drugs are strategies suggested in clinical guidelines as initial treatment of hypertension. The recommendations are not based on evidence about clinically relevant outcomes. Some antihypertensive combinations have been shown to be harmful. The actual harm-to-benefit balance of each strategy is unknown.

OBJECTIVES

To determine if there are differences in clinical outcomes between monotherapy and combination therapy as initial treatment for primary hypertension.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to April 2019: the Cochrane Hypertension Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 2005), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. We used no language restrictions. We also searched clinical studies repositories of pharmaceutical companies, reviews of combination drugs on the US Food and Drug Administration and European Medicines Agency websites, and lists of references in reviews and clinical practice guidelines.

SELECTION CRITERIA

We included randomised, double-blind trials with at least 12 months' follow-up in adults with primary hypertension (systolic blood pressure/diastolic blood pressure 140/90 mmHg or higher, or 130/80 mmHg or higher if participants had diabetes), which compared combination of two first-line antihypertensive drugs with monotherapy as initial treatment. Trials had to include at least 50 participants per group and report mortality, cardiovascular mortality, cardiovascular events, or serious adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, evaluated the risk of bias, and performed data entry. The primary outcomes were mortality, serious adverse events, cardiovascular events, and cardiovascular mortality. Secondary outcomes were withdrawals due to drug-related adverse effects, reaching blood pressure control (as defined in each trial), and blood pressure change from baseline. Analyses were based on the intention-to-treat principle. We summarised data on dichotomous outcomes as risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

This update included one new study in which a subgroup of participants met our inclusion criteria. As none of the four included studies focused solely on people initiating antihypertensive treatment, we asked investigators for data for this subgroup. One study (PREVER-treatment 2016) used a combination of thiazide-type diuretic/potassium-sparing diuretic; as the former is not indicated in monotherapy, we analysed this study separately. The three original trials in the main comparison (monotherapy: 335 participants; combination therapy: 233 participants) included outpatients, mostly European and white people. Two trials only included people with type 2 diabetes; the remaining trial excluded people treated with diabetes, hypocholesterolaemia, or cardiovascular drugs. The follow-up was 12 months in two trials and 36 months in one trial. It is very uncertain whether combination therapy versus monotherapy reduces total mortality (RR 1.35, 95% CI 0.08 to 21.72), cardiovascular mortality (zero events reported), cardiovascular events (RR 0.98, 95% CI 0.22 to 4.41), serious adverse events (RR 0.77, 95% CI 0.31 to 1.92), or withdrawals due to adverse effects (RR 0.85, 95% CI 0.53 to 1.35); all outcomes had 568 participants, and the evidence was rated as of very low certainty due to serious imprecision and for using a subgroup that was not defined in advance. The confidence intervals were extremely wide for all important outcomes and included both appreciable harm and benefit. The PREVER-treatment 2016 trial, which used a combination therapy with potassium-sparing diuretic (monotherapy: 84 participants; combination therapy: 116 participants), included outpatients. This trial was conducted in Brazil and had a follow-up of 18 months. The number of events was very low and confidence intervals very wide, with zero events reported for cardiovascular mortality and withdrawals due to adverse events. It is very uncertain if there are differences in clinical outcomes between monotherapy and combination therapy in this trial.

AUTHORS' CONCLUSIONS

The numbers of included participants, and hence the number of events, were too small to draw any conclusion about the relative efficacy of monotherapy versus combination therapy as initial treatment for primary hypertension. There is a need for large clinical trials that address the review question and report clinically relevant endpoints.

Hypertension Drug Therapy

Hypertension is still the number one global killer. No matter what causes are, lowering blood pressure can significantly reduce cardiovascular complications, cardiovascular death, and total death. Unfortunately, some hypertensive individuals simply do not know having hypertension. Some knew it but either not being treated or treated but blood pressure does not achieve goal. The reasons for inadequate control of blood pressure are many. One important reason is that we are not very familiar with antihypertensive agents and less attention has been paid to comorbidities, complications as well as the hypertension-modified target organ damage in patients with hypertension. The right antihypertensive drug was not given to the right hypertensive patients at right time. This reviewer studied comprehensively the literature, hopefully that the review will help improve antihypertensive drug selection and antihypertensive therapy.

Efficacy of chlorthalidone and hydrochlorothiazide in combination with amiloride in multiple doses on blood pressure in patients with primary hypertension: a protocol for a factorial randomized controlled trial

BACKGROUND

Thiazide diuretics have demonstrated favorable blood pressure lowering efficacy, but the equivalent doses of their more common agents, chlorthalidone and hydrochlorothiazide, are still unclear. Further, concerns exist regarding adverse metabolic effects, which may be attenuated with the concomitant administration of a potassium-sparing diuretic, such as amiloride. This trial aims to investigate the efficacy of chlorthalidone and hydrochlorothiazide, in combination with amiloride at different doses, for initial management of patients with primary hypertension.

METHODS/DESIGN

This is a factorial (2 × 2) randomized double-blinded clinical trial comparing the association of a thiazide diuretic (chlorthalidone 25 mg/day or hydrochlorothiazide 50 mg/day) with a potassium-sparing diuretic (amiloride 10 mg/day or amiloride 20 mg/day) in patients with primary hypertension. The primary outcome will be the mean change from baseline in 24-h systolic and diastolic blood pressure measured by ambulatory blood pressure monitoring. The secondary outcomes will be the mean change from baseline in daytime and nighttime systolic and diastolic blood pressure measured by ambulatory blood pressure monitoring, mean change from baseline in systolic and diastolic blood pressure measured by office blood pressure, incidence of adverse events, variation of laboratory parameters, and proportion of patients who achieved blood pressure control. The follow-up will last 12 weeks. For a P alpha of 0.05, power of 80%, standard deviation of 9 mmHg, and absolute difference of 6 mmHg on systolic blood pressure on 24-h ambulatory blood pressure monitoring, it will be necessary to study a total of 76 patients. The sample size will be increased by 10% to compensate for losses, resulting in 84 patients being randomized.

DISCUSSION

Diuretics are pivotal drugs for the treatment of hypertension. Chlorthalidone and hydrochlorothiazide, in combination with amiloride in multiple doses, will be tested in terms of blood pressure lowering efficacy and safety. Since the intensity of blood pressure reduction is the major determinant of reduction in cardiovascular risk in hypertensive patients, this study will help to determine which combination of diuretics represents the most appropriate treatment for this population.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03928145. Registered on 25 April 2019. Last update on 29 April 2019.

First-line combination therapy versus first-line monotherapy for primary hypertension

BACKGROUND

Starting with one drug and starting with a combination of two drugs are strategies suggested in clinical guidelines as initial treatment of hypertension. The recommendations are not based on evidence about clinically relevant outcomes. Some antihypertensive combinations have been shown to be harmful. The actual harm-to-benefit balance of each strategy is unknown.

OBJECTIVES

To determine if there are differences in clinical outcomes between monotherapy and combination therapy as initial treatment for primary hypertension.

SEARCH METHODS

We searched the Hypertension Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, 2016, Issue 2), Ovid MEDLINE, Ovid Embase, LILACS, ClinicalTrials.gov, Current Controlled Trials, and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) up to February 2016. We searched in clinical studies repositories of pharmaceutical companies, reviews of combination drugs in Food and Drug Administration and European Medicines Agency, and lists of references in reviews and clinical practice guidelines.

SELECTION CRITERIA

Randomized, double-blind trials with at least 12 months' follow-up in adults with primary hypertension (systolic blood pressure/diastolic blood pressure 140/90 mmHg or higher, or 130/80 mmHg or higher if participants had diabetes), which compared combination of two first-line antihypertensive drug with monotherapy as initial treatment. Trials had to include at least 50 participants per group and report mortality, cardiovascular mortality, cardiovascular events or serious adverse events.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion, evaluated the risk of bias and entered the data. Primary outcomes were mortality, serious adverse events, cardiovascular events and cardiovascular mortality. Secondary outcomes were withdrawals due to drug-related adverse effects, reaching blood pressure control (as defined in each trial) and blood pressure change from baseline. Analyses were based on the intention-to-treat principle. We summarized data on dichotomous outcomes as risk ratios with 95% confidence intervals.

MAIN RESULTS

We found three studies in which a subgroup of participants met our inclusion criteria. None of the studies focused solely on people initiating antihypertensive treatment so we asked investigators for data for this subgroup (monotherapy: 335 participants; combination therapy: 233 participants). They included outpatients, and mostly European and white people. Two trials included only people with type 2 diabetes, whereas the other trial excluded people treated with diabetes, hypocholesterolaemia or cardiovascular drugs. The follow-up was 12 months in two trials and 36 months in one trial. Certainty of evidence was very low due to the serious imprecision, and for using a subgroup not defined in advance. Confidence intervals were extremely wide for all important outcomes and included both appreciable harm and benefit.

AUTHORS' CONCLUSIONS

The numbers of included participants and, hence the number of events, were too small to draw any conclusion about the relative efficacy of monotherapy versus combination therapy as initial treatment for primary hypertension. There is a need for large clinical trials that address the question and report clinically relevant endpoints.

Not just chlorthalidone: evidence-based, single tablet, diuretic alternatives to hydrochlorothiazide for hypertension

Accounting for 15 % of deaths worldwide, hypertension is often treated with hydrochlorothiazide (HCTZ) (50 million prescriptions annually). HCTZ has a <24-h duration of action, is less potent than chlorthalidone and all major antihypertensive drug classes, and is inferior to four antihypertensive drugs for cardiovascular event (CVE) reduction. If there were alternative diuretics, why prescribe HCTZ? Chlorthalidone is often offered as an alternative to HCTZ, but has limited pharmaceutical formulations. However, there are seven evidence-based, single-tablet, alternative diuretics. For reducing CVE, the following are superior to their comparators: chlorthalidone versus four antihypertensives in multiple hypertensive populations; indapamide versus placebo in elderly Chinese (and versus enalapril for left ventricular hypertrophy), triamterene-HCTZ versus placebo in elderly Europeans, amiloride-HCTZ versus three antihypertensives, and indapamide-perindopril versus placebo in three populations. Additionally, chlorthalidone-azilsartan and spironolactone-HCTZ are potent combinations The aldosterone antagonist component of the latter combination has been shown to reduce total mortality by 30 % in heart failure. Five of these seven have multiple dose formulations. Six cost $4-$77 monthly. In conclusion, based on both scientific and practical grounds, new prescriptions for HCTZ are rarely justified.

Triamterene Enhances the Blood Pressure Lowering Effect of Hydrochlorothiazide in Patients with Hypertension

BACKGROUND

Triamterene, because of its potassium-sparing properties, is frequently used in combination with hydrochlorothiazide (HCTZ) to treat patients with hypertension. By inhibiting the epithelial sodium channel (ENaC) in the cortical collecting duct, triamterene reduces potassium secretion, thus reducing the risk of hypokalemia. Whether triamterene has an independent effect on blood pressure (BP) has not been well studied.

OBJECTIVE

To determine if triamterene provides an effect to further lower BP in patients treated with HCTZ.

DESIGN

We conducted an observational study using electronic medical record data from the Indiana Network for Patient Care. Participants were 17,291 patients with the diagnosis of hypertension between 2004 and 2012.

MAIN MEASURES

BP was the primary outcome. We compared the BP between patients who were taking HCTZ, with and without triamterene, either alone or in combination with other antihypertensive medications, by using a propensity score analysis. For each medication combination, we estimated the propensity score (i.e., probability) of a patient receiving triamterene using a logistic regression model. Patients with similar propensity scores were stratified into subclasses and BP was compared between those taking triamterene or not within each subclass; the effect of triamterene was then assessed by combining BP differences estimated from all subclasses.

KEY RESULTS

The mean systolic BP in the triamterene + HCTZ group was 3.8 mmHg lower than in the HCTZ only group (p < 0.0001); systolic BP was similarly lower for patients taking triamterene with other medication combinations. Systolic BP reduction was consistently observed for different medication combinations. The range of systolic BP reduction was between 1 and 4 mm Hg, depending on the concurrently used medications.

CONCLUSIONS

In the present study, triamterene was found to enhance the effect of HCTZ to lower BP. In addition to its potassium-sparing action, triamterene's ability to lower BP should also be considered.

An assessment of randomized controlled trials (RCTs) for non-communicable diseases (NCDs): more and higher quality research is required in less developed countries

Research is crucial to implement evidence-based health interventions for control of non-communicable diseases (NCDs). This study aims to assess main features of randomized controlled trials (RCTs) for control of NCDs, and to identify gaps in clinical research on NCDs between high-income and less developed countries. The study included 1177 RCTs in 82 Cochrane Systematic reviews (CSRs) and evaluated interventions for adults with hypertension, diabetes, stroke, or heart diseases. Multivariate logistic regression analyses were conducted to explore factors associated with risk of bias in included RCTs. We found that 78.2% of RCTs of interventions for major NCDs recruited patients in high-income countries. The number of RCTs included in the CSRs was increasing over time, and the increasing speed was more noticeable for RCTs conducted in middle-income countries. RCTs conducted in less developed countries tended to be more recently published, less likely to be published in English, with smaller sample sizes, and at a higher risk of bias. In conclusion, there is still a lack of research evidence for control of NCDs in less developed countries. To brace for rising NCDs and avoid waste of scarce research resources, not only more but also higher quality clinical trials are required in low-and-middle-income countries.

Current perspectives on treatment of hypertensive patients with chronic obstructive pulmonary disease

Systemic hypertension and chronic obstructive pulmonary disease (COPD) frequently coexist in the same patient, especially in the elderly. Today, a wide variety of antihypertensive drugs with different mechanisms of action are available to the prescribing physician. In addition, combination drugs for hypertension are becoming increasingly popular. Certain antihypertensive drugs can affect pulmonary function. Therefore the management of such patients can present therapeutic challenges. We have examined the literature pertaining to the use of antihypertensive drugs in patients with systemic hypertension and coexisting COPD. Although data are often limited or of poor quality, we have attempted to review and then provide recommendations regarding the use of all the specific classes of antihypertensive drug therapies including combination drugs in patients with COPD. The antihypertensive agents reviewed include diuretics, aldosterone receptor blockers, beta blockers, combined alpha and beta blockers, angiotensin-converting enzyme inhibitors, angiotensin II antagonists, calcium channel blockers, alpha-1 blockers, centrally acting drugs, direct vasodilators, and combinations of these drugs. Of these classes, calcium channel blockers and angiotensin II antagonists appear to be the best initial choices if hypertension is the only indication for treatment. However, the limited data available on many of these drugs suggest that additional studies are needed to more precisely determine the best treatment choices in this widely prevalent patient group.