Telephone informed consent in a pragmatic point-of-care clinical trial embedded in primary care.

BACKGROUND: One benefit of pragmatic clinical trials is reduction of the burden on patients and clinical staff while facilitating a learning healthcare system. One way to decrease the work of clinical staff is through decentralized telephone consent. METHODS: The Diuretic Comparison Project (DCP) was a nationwide Point of Care pragmatic clinical trial conducted by the VA Cooperative Studies Program. The purpose of the trial was to compare the clinical effectiveness on major CV outcomes of two commonly used diuretics, hydrochlorothiazide and chlorthalidone, in an elderly patient population. Telephone consent was allowed for this study because of its minimal risk designation. Telephone consent was more difficult than initially anticipated and the study team constantly adjusted methods to find timely solutions. RESULTS: The major challenges can be categorized as call center-related, telecommunications, operational, and study population based. In particular, the possible technical and operational pitfalls are rarely discussed. By presenting hurdles here, future studies may avoid these challenges and start studies with a more effective system in place. CONCLUSIONS: DCP is a novel study designed to answer an important clinical question. The lessons learned from implementing a centralized call center for the Diuretic Comparison Project helped the study reach enrollment goals and develop a centralized telephone consent system that can be utilized for future pragmatic and explanatory clinical trials. CLINICAL TRIAL REGISTRATION: The study is registered on ClinicalTrials.gov; NCT02185417 [https://clinicaltrials.gov/ct2/show/NCT02185417]. The contents do not represent the views of the U.S. Department of Veterans Affairs or the United States Government.

The impact of COVID-19 on a large pragmatic clinical trial embedded in primary care.

INTRODUCTION: The COVID-19 pandemic had significant impact on clinical care and clinical trial operations, but the impact on decentralized pragmatic trials is unclear. The Diuretic Comparison Project (DCP) is a Point-of Care (POC) pragmatic trial testing whether chlorthalidone is superior to hydrochlorothiazide in preventing major cardiovascular (CV) events and non-cancer death. DCP utilized telephone consent, data collection from the electronic health record and Medicare, forwent study visits, and limited provider commitment beyond usual care. We assessed the impact of COVID-19 on recruitment, follow-up, data collection, and outcome ascertainment in DCP. METHODS: We compared data from two 8-month periods: Pre-Pandemic (July 2019-February 2020) and Mid-Pandemic (July 2020-February 2021). Consent and randomization rates, diuretic adherence, blood pressure (BP) and electrolyte follow-up rates, records of CV events, hospitalization, and death rates were compared. RESULTS: Providers participated at a lower rate mid-pandemic (65%) than pre-pandemic (71%), but more patients were contacted (7622 vs. 5363) and consented (3718 vs. 3048) mid-pandemic than pre-pandemic. Patients refilled medications and remained on their randomized diuretic equally (90%) in both periods. Overall, rates of BP, electrolyte measurements, and hospitalizations decreased mid-pandemic while deaths increased. CONCLUSIONS: While recruitment, enrollment, and adherence did not suffer during the pandemic, documented blood pressure checks and laboratory evaluations decreased, likely due to fewer in-person visits. VA hospitalizations decreased, despite a considerable number of COVID-related hospitalizations. This suggests changes in clinical care during the pandemic, but the limited impact on DCP's operations during a global pandemic is an important strength of POC trials. CLINICAL TRIAL REGISTRATION: NCT02185417.

Chlorthalidone vs. Hydrochlorothiazide for Hypertension-Cardiovascular Events.

BACKGROUND: Whether chlorthalidone is superior to hydrochlorothiazide for preventing major adverse cardiovascular events in patients with hypertension is unclear. METHODS: In a pragmatic trial, we randomly assigned adults 65 years of age or older who were patients in the Department of Veterans Affairs health system and had been receiving hydrochlorothiazide at a daily dose of 25 or 50 mg to continue therapy with hydrochlorothiazide or to switch to chlorthalidone at a daily dose of 12.5 or 25 mg. The primary outcome was a composite of nonfatal myocardial infarction, stroke, heart failure resulting in hospitalization, urgent coronary revascularization for unstable angina, and non-cancer-related death. Safety was also assessed. RESULTS: A total of 13,523 patients underwent randomization. The mean age was 72 years. At baseline, hydrochlorothiazide at a dose of 25 mg per day had been prescribed in 12,781 patients (94.5%). The mean baseline systolic blood pressure in each group was 139 mm Hg. At a median follow-up of 2.4 years, there was little difference in the occurrence of primary-outcome events between the chlorthalidone group (702 patients [10.4%]) and the hydrochlorothiazide group (675 patients [10.0%]) (hazard ratio, 1.04; 95% confidence interval, 0.94 to 1.16; P = 0.45). There were no between-group differences in the occurrence of any of the components of the primary outcome. The incidence of hypokalemia was higher in the chlorthalidone group than in the hydrochlorothiazide group (6.0% vs. 4.4%, P<0.001). CONCLUSIONS: In this large pragmatic trial of thiazide diuretics at doses commonly used in clinical practice, patients who received chlorthalidone did not have a lower occurrence of major cardiovascular outcome events or non-cancer-related deaths than patients who received hydrochlorothiazide. (Funded by the Veterans Affairs Cooperative Studies Program; ClinicalTrials.gov number, NCT02185417.).

Design of a pragmatic clinical trial embedded in the Electronic Health Record: The VA's Diuretic Comparison Project.

BACKGROUND: Recent US guidelines recommend chlorthalidone over other thiazide-type diuretics for the treatment of hypertension based on its long half-life and proven ability to reduce CVD events. Despite recommendations most clinicians prescribe hydrochlorothiazide (HCTZ) over chlorthalidone (CTD). No randomized controlled data exist comparing these two diuretics on cardiovascular outcomes. METHODS: The Diuretic Comparison Project (DCP) is a multicenter, two-arm, parallel, Prospective Randomized Open, Blinded End-point (PROBE) trial testing the primary hypothesis that CTD is superior to HCTZ in the prevention of non-fatal CVD events and non-cancer death. Patients with hypertension taking HCTZ 25 or 50 mg were randomly assigned to either continue their current HCTZ or switch to an equipotent dose of CTD. The primary outcome is time to the first occurrence of a composite outcome consisting of a non-fatal CVD event (stroke, myocardial infarction, urgent coronary revascularization because of unstable angina, or hospitalization for acute heart failure) or non-cancer death. The trial randomized 13,523 patients at 72 VA medical centers. The study is conducted by a centralized research team with site procedures embedded in the electronic health record and all data collected through administrative claims data, with no study related visits for participants. The trial will have 90% power to detect an absolute reduction in the composite event rate of 2.4%. RESULTS: Enrollment ended in November 2021. There are 4128 participting primary care providers and 16,595 patients individually consented to participate, 13,523 of whom were randomized. CONCLUSIONS: DCP should provide much needed evidence as to whether CTD is superior to HCTZ in preventing cardiovascular events in hypertensive patients. CLINICAL TRIAL REGISTRATION: NCT02185417 [https://clinicaltrials.gov/ct2/show/NCT02185417].