The Comparative Effectiveness of Hydrochlorothiazide and Chlorthalidone in an Observational Cohort of Veterans

Comparison of the Effectiveness and Safety of Chlorthalidone and Hydrochlorothiazide in Patients With Hypertension: A Meta-Analysis

The aim of this study was to compare the effectiveness and safety of chlorthalidone and hydrochlorothiazide in patients with hypertension. The present meta-analysis was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our search for relevant articles was conducted on PubMed, Scopus, and CINAHIL databases from their inception until March 31, 2023. Keywords used to search for relevant articles included "hydrochlorothiazide," "chlortalidone," "hypertension," "cardiovascular," and "blood pressure." The outcomes assessed in this meta-analysis included changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP). Myocardial infarction, stroke, and all-cause mortality were also assessed. For safety analysis, we evaluated the risk of hypokalemia between the two groups. Any disagreement between the two authors in the data extraction process was resolved through discussion. Eight studies fulfilled the inclusion criteria included in the present meta-analysis. Our analysis showed that chlorthalidone was superior to hydrochlorothiazide in controlling both SBP and DBP, with no significant heterogeneity reported. However, there was no significant difference between the two groups in terms of the risk of myocardial infarction, stroke, all-cause mortality, and hospitalization due to heart failure. The hypokalemia rate was reported to be higher with chlorthalidone compared to hydrochlorothiazide.

Comparison of Clinical Outcomes and Safety Associated With Chlorthalidone vs Hydrochlorothiazide in Older Adults With Varying Levels of Kidney Function

IMPORTANCE

Thiazide diuretics are commonly prescribed for the treatment of hypertension, a disease highly prevalent among older individuals and in those with chronic kidney disease. How specific thiazide diuretics compare in regard to safety and clinical outcomes in these populations remains unknown.

OBJECTIVE

To compare safety and clinical outcomes associated with chlorthalidone or hydrochlorothiazide use among older adults with varying levels of kidney function.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study was conducted in Ontario, Canada, from 2007 to 2015. Participants included adults aged 66 years or older who initiated chlorthalidone or hydrochlorothiazide during this period. Data were analyzed from December 2019 through September 2020.

EXPOSURES

New chlorthalidone users were matched 1:4 with new hydrochlorothiazide users by a high-dimensional propensity score. Time-to-event models accounting for competing risks examined the associations between chlorthalidone vs hydrochlorothiazide use and the outcomes of interest overall and within estimated glomerular filtration rate (eGFR) categories (≥60, 45-59, and <45 mL/min/1.73 m2).

MAIN OUTCOMES AND MEASURES

The outcomes of interest were adverse kidney events (ie, eGFR decline ≥30%, dialysis, or kidney transplantation), cardiovascular events (composite of myocardial infarction, coronary revascularization, heart failure, or atrial fibrillation), all-cause mortality, and electrolyte anomalies (ie, sodium or potassium levels outside reference ranges).

RESULTS

After propensity score matching, the study cohort included 12 722 adults (mean [SD] age, 74 [7] years; 7063 [56%] women; 5659 [44%] men; mean [SD] eGFR, 69 [19] mL/min/1.73 m2), including 2936 who received chlorthalidone and 9786 who received hydrochlorothiazide. Chlorthalidone use was associated with a higher risk of eGFR decline of 30% or greater (hazard ratio [HR], 1.24 [95% CI, 1.13-1.36]) and cardiovascular events (HR, 1.12 [95% CI, 1.04-1.22]) across all eGFR categories compared with hydrochlorothiazide use. Chlorthalidone use was also associated with a higher risk of hypokalemia compared with hydrochlorothiazide use, which was more pronounced among those with higher eGFR (eGFR ≥60 mL/min/1.73 m2: HR, 1.86 [95% CI, 1.67-2.08]; eGFR 45-59 mL/min/1.73 m2: HR, 1.57 [95% CI, 1.25-1.96]; eGFR <45 mL/min/1.73 m2: HR, 1.10 [95% CI, 0.84-1.45]; P for interaction = .001). No significant differences were observed between chlorthalidone and hydrochlorothiazide for dialysis or kidney transplantation (HR, 1.44 [95% CI, 0.88-2.36]), all-cause mortality (HR, 1.10 [95% CI, 0.93-1.29]), hyperkalemia (HR, 1.05 [95% CI, 0.79-1.39]), or hyponatremia (HR, 1.14 [95% CI, CI 0.98-1.32]).

CONCLUSIONS AND RELEVANCE

This cohort study found that among older adults, chlorthalidone use was associated with a higher risk of eGFR decline, cardiovascular events, and hypokalemia compared with hydrochlorothiazide use. The excess risk of hypokalemia with chlorthalidone was attenuated in participants with reduced kidney function. Placed in context with prior observational studies comparing the safety and clinical outcomes associated with thiazide diuretics, these results suggest that there is no evidence to prefer chlorthalidone over hydrochlorothiazide.

Synchronous Spectrofluorimetry Coupled with Third-Order Derivative Signal Processing for the Simultaneous Quantitation of Telmisartan and Chlorthalidone Drug Combination in Human Plasma

This study is the first to develop and optimize a method for the simultaneous determination of chlorthalidone (CLT) and telmisartan (TEL) in, human plasma samples as well as in their newly released pharmaceutical tablet form, (Telmikind-CT 40®). The method is based on measuring fluorescence intensity, employing synchronous fluorescence mode coupled to third-order derivative signal processing, 0.5% w/v cetyl trimethyl ammonium bromide was used as cationic surfactant to enhance the fluorescence signal intensity and improve method sensitivity. The third-order derivative synchronous spectra of CLT and TEL are well separated with two zero-crossing points which allowed for the determination of CLT and TEL at 362 nm and 351 nm, respectively. Different experimental parameters were carefully investigated and optimized, calibration curves were constructed over concentration ranges of 20-1200 ng.mL^-1 and 5-800 ng.mL^-1 for CLT and TEL respectively. The developed method is simple and rapid, analytical parameters were validated according to ICH guidelines and high sensitivity was achieved as represented by limits of detection (LOD) of 4.69 and 1.58 ng.mL^-1 for CLT and TEL respectively.

Single-pill Combination Therapy of Azilsartan Medoxomil/Chlorthalidone for Treatment of Hypertension: A Systematic Review

PURPOSE

The goal of this study was to review recent clinical studies of azilsartan medoxomil (AZL-M) and chlorthalidone (CLD), a combined angiotensin receptor blocker and thiazide-like diuretic, and its role in recently published guidelines. This review explores the role of AZL-M/CLD in treating patients with hypertension.

METHODS

A systematic review of literature published from 1990 to 2018 was performed by using the following key words: Edarbyclor, azilsartan, chlorthalidone, pharmacokinetic, and hypertension. Available English-language data from reviews, abstracts, presentations, and clinical trials regarding the use of AZL-M/CLD therapy specifically detailing effects of lowering blood pressure (BP) and outcomes on cardiovascular disease in humans and rats were reviewed.

FINDINGS

One study compared a single-pill combination of AZL-M/CLD with co-administration of AZL-M and hydrochlorothiazide and found a greater reduction in clinic systolic BP with AZL-M/CLD (-35.1 mm Hg vs -29.5 mm Hg) than for AZL-M and hydrochlorothiazide. Another study of 153 patients with chronic kidney disease who received AZL-M/CLD or other single-pill combination agents found that AZL-M/CLD was more effective in lowering BP, achieving superior adherence. According to new guidelines, an increase in the prevalence of resistant hypertension can occur as a result of trying to lower target BP.

IMPLICATIONS

A powerful and effective medication that can increase patient compliance is essential to reduce the incidence of resistant hypertension. AZL-M/CLD is a powerful and safe antihypertensive medication that has been thoroughly studied in patients with hypertension.

Pharmacogenomics of Hypertension Treatment

Hypertension is one of the strongest modifiable cardiovascular risk factors, affecting an increasing number of people worldwide. Apart from poor medication adherence, the low efficacy of some therapies could also be related to inter-individual genetic variability. Genetic studies of families revealed that heritability accounts for 30% to 50% of inter-individual variation in blood pressure (BP). Genetic factors not only affect blood pressure (BP) elevation but also contribute to inter-individual variability in response to antihypertensive treatment. This article reviews the recent pharmacogenomics literature concerning the key classes of antihypertensive drugs currently in use (i.e., diuretics, β-blockers, ACE inhibitors, ARB, and CCB). Due to the numerous studies on this topic and the sometimes-contradictory results within them, the presented data are limited to several selected SNPs that alter drug response. Genetic polymorphisms can influence drug responses through genes engaged in the pathogenesis of hypertension that are able to modify the effects of drugs, modifications in drug–gene mechanistic interactions, polymorphisms within drug-metabolizing enzymes, genes related to drug transporters, and genes participating in complex cascades and metabolic reactions. The results of numerous studies confirm that genotype-based antihypertension therapies are the most effective and may help to avoid the occurrence of major adverse events, as well as decrease the costs of treatment. However, the genetic heritability of drug response phenotypes seems to remain hidden in multigenic and multifactorial complex traits. Therefore, further studies are required to analyze all associations and formulate final genome-based treatment recommendations.

Pharmacogenomics of amlodipine and hydrochlorothiazide therapy and the quest for improved control of hypertension: a mini review

Blood pressure (BP) is a complex trait that is regulated by multiple physiological pathways and include but is not limited to extracellular fluid volume homeostasis, cardiac contractility, and vascular tone through renal, neural, or endocrine systems. Uncontrolled hypertension (HTN) has been associated with an increased mortality risk. Therefore, understanding the genetics that underpins and influence BP regulation will have a major impact on public health. Moreover, uncontrolled HTN has been linked to inter-individual variation in the drugs’ response and this has been associated with an individual’s genetics architecture. However, the identification of candidate genes that underpin the genetic basis of HTN remains a major challenge. To date, few variants associated with inter-individual BP regulation have been identified and replicated. Research in this field has accelerated over the past 5 years as a direct result of on-going genome-wide association studies (GWAS) and the progress in the identification of rare gene variants and mutations, epigenetic markers, and the regulatory pathways involved in the pathophysiology of BP. In this review we describe and enhance our current understanding of how genetic variants account for the observed variability in BP response in patients on first-line antihypertensive drugs, amlodipine and hydrochlorothiazide.

A randomized trial of the efficacy and safety of azilsartan medoxomil combined with chlorthalidone

INTRODUCTION

We measured the effects of azilsartan medoxomil co-administered with chlorthalidone 25 mg in stage 2 hypertension.

METHODS

Azilsartan medoxomil 40 or 80 mg plus chlorthalidone were compared with placebo plus chlorthalidone once daily in a randomized, double-blind, 6-week trial. The primary endpoint was change from baseline in 24-hour mean systolic blood pressure by ambulatory blood pressure monitoring.

RESULTS

Patients ( N=551; mean age 59 years; 51.7% men) were randomly assigned to placebo plus chlorthalidone ( n=184), azilsartan medoxomil 40 mg plus chlorthalidone ( n=185), or azilsartan medoxomil 80 mg plus chlorthalidone ( n=182). Baseline systolic blood pressures were similar among groups. After 6 weeks, least squares mean (standard error) reductions with azilsartan medoxomil 40 mg and 80 mg plus chlorthalidone were similar in magnitude (-31.7 (1.0) and -31.3 (1.0) mmHg, respectively), but greater than chlorthalidone alone (-15.9 (1.0) mmHg). Hypotension and serum creatinine elevations were more frequent with azilsartan medoxomil plus chlorthalidone than chlorthalidone alone (reversed with drug discontinuation). Notably, plasma potassium reduction of 0.43 meq/L with chlorthalidone was attenuated to 0.13 and 0.05 meq/L by azilsartan medoxomil 40 mg and 80 mg, respectively.

CONCLUSION

Azilsartan medoxomil 40 mg or 80 mg plus chlorthalidone 25 mg was significantly more efficacious than chlorthalidone alone in reducing blood pressure and was well tolerated. Clinicaltrial.gov , https://clinicaltrials.gov/ct2/show/NCT00591773 , NCT00591773.

Rural access to clinical pharmacy services

OBJECTIVES

To examine the impact of rural residence and primary care site on use of clinical pharmacy services (CPS) and to describe the use of clinical telepharmacy within the Veterans Health Administration (VHA) health care system.

METHODS

Using 2011 national VHA data, the frequency of patients with CPS encounters was compared across patient residence (urban or rural) and principal site of primary care (medical center, urban clinic, or rural clinic). The likelihood of CPS utilization was estimated with random effects logistic regression. Individual service types (e.g., anticoagulation clinics) and delivery modes (e.g., telehealth) were also examined.

RESULTS

Of 3,040,635 patients, 711,348 (23.4%) received CPS. Service use varied by patient residence (urban: 24.9%; rural: 19.7%) and principal site of primary care (medical center: 25.9%; urban clinic: 22.5%; rural clinic: 17.6%). However, in adjusted analyses, urban-rural differences were explained primarily by primary care site and less so by patient residence. Similar findings were observed for individual CPS types. Telehealth encounters were common, accounting for nearly one-half of patients receiving CPS. Video telehealth was infrequent (<0.2%), but more common among patients of rural clinics than those receiving CPS at medical centers (odds ratio [OR] = 9.7; 95% CI 9.0-10.5).

CONCLUSION

We identified a potential disparity between rural and urban patients' access to CPS, which was largely explained by greater reliance on community clinics for primary care than on medical centers. Future research is needed to determine if this disparity will be alleviated by emerging organizational changes, including expanding telehealth capacity and integrating pharmacists into primary care teams, and whether lessons learned at VHA translate to other settings.

Engineering practice variation through provider agreement: a cluster-randomized feasibility trial

Purpose

Minimal-risk randomized trials that can be embedded in practice could facilitate learning health-care systems. A cluster-randomized design was proposed to compare treatment strategies by assigning clusters (eg, providers) to “favor” a particular drug, with providers retaining autonomy for specific patients. Patient informed consent might be waived, broadening inclusion. However, it is not known if providers will adhere to the assignment or whether institutional review boards will waive consent. We evaluated the feasibility of this trial design.

Subjects and methods

Agreeable providers were randomized to “favor” either hydrochlorothiazide or chlorthalidone when starting patients on thiazide-type therapy for hypertension. The assignment applied when the provider had already decided to start a thiazide, and providers could deviate from the strategy as needed. Prescriptions were aggregated to produce a provider strategy-adherence rate.

Results

All four institutional review boards waived documentation of patient consent. Providers (n=18) followed their assigned strategy for most of their new thiazide prescriptions (n=138 patients). In the “favor hydrochlorothiazide” group, there was 99% adherence to that strategy. In the “favor chlorthalidone” group, chlorthalidone comprised 77% of new thiazide starts, up from 1% in the pre-study period. When the assigned strategy was followed, dosing in the recommended range was 48% for hydrochlorothiazide (25–50 mg/day) and 100% for chlorthalidone (12.5–25.0 mg/day). Providers were motivated to participate by a desire to contribute to a comparative effectiveness study. A study promotional mug, provider information letter, and interactions with the site investigator were identified as most helpful in reminding providers of their study drug strategy.

Conclusion

Providers prescribed according to an assigned drug-choice strategy most of the time for the purpose of a comparative effectiveness study. This simple design could facilitate research participation and behavior change in non-research clinicians. Waiver of patient consent can broaden the representation of patients, providers, and settings.

Is chlorthalidone better than hydrochlorothiazide in reducing cardiovascular events in hypertensives?

PURPOSE OF REVIEW

Hydrochlorthiazide (HCTZ) is the tenth most commonly prescribed drug in recent data. Although no head-to-head trials compare HCTZ with the uncommonly prescribed chlorthalidone (CTDN) in reducing cardiovascular events (CVEs), numerous other data are available.

RECENT FINDINGS

Head-to-head trials have shown CTDN's superiority in antihypertensive potency, particularly during the critical nighttime period (SBP difference 7.1 mmHg), due to the differences in duration of action (16-24 h for HCTZ versus 48-72 h for CTDN). In an observational cohort study, compared with HCTZ, CTDN was associated with lower left ventricular hypertrophy. In another observational cohort analysis (n = 12,866), the percentage risk reduction in CVEs from CTDN versus HCTZ was 21 [95% confidence interval (CI) 8-32], P = 0.002. In network meta-analyses of randomized trials (n = 50,946), CTDN was superior to HCTZ in reducing congestive heart failure and in reducing all CVEs: percentage risk reduction 21 (95% CI 12-28), P < 0.0001. A statistically significant reduction in CVEs by CTDN versus HCTZ persisted even when reduction in office SBP produced by the two diuretics was identical, further strengthening the case for CTDN.

SUMMARY

Direct and indirect evidence demonstrates that CTDN is superior to HCTZ in reducing CVEs and is congruent with the recent changes in the guidelines for hypertension management.

Optimizing combination therapy in the management of hypertension: the role of the aliskiren, amlodipine, and hydrochlorothiazide fixed combination

High blood pressure is the leading risk factor for death and disability worldwide, and the prevalence is increasing. Effective treatment decreases the risk of adverse events in proportion to blood pressure reduction. Combination antihypertensive therapy reduces blood pressure promptly and effectively. Single-pill combinations reduce the pill burden and improve adherence, efficacy, and tolerability of treatment compared with single drug pills. A significant portion of the hypertensive population will require three drugs for adequate control. The single-pill combination of aliskiren, amlodipine, and hydrochlorothiazide is based on complementary mechanisms of action. Clinical trials have shown it to be a safe and effective treatment for hypertension. This combination is a reasonable choice in clinical practice for patients with hypertension that requires three drugs for effective treatment.