Development of the Double-Blind, Randomized Trials of Effects of Antihypertensive Medicines (DREAM) Database and Characteristics of the Included Trials: Protocol for an Umbrella Review and Meta-Analyses

Background: A comprehensive evaluation of short-term effects of antihypertensive medicines is important for informing guidelines and clinical practice. Objective: We aimed to develop the Double-blind Randomized trials of Effects of Antihypertensive Medicines (DREAM) database to facilitate a series of meta-analyses evaluating the short-term effects of antihypertensive medicines. Methods: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Epistemonikos from inception until December 2022 to identify relevant randomized clinical trials (RCTs). We included RCTs in the DREAM database if they were double-blind, enrolled adult participants, evaluated the 5 major classes of antihypertensive medicines over a duration of 2 to 26 weeks, and were published in the English language. Screening of records for inclusion and data collection were both conducted in duplicate. The planned meta-analyses using the DREAM database will follow standard methods as recommended by the Cochrane Handbook for Systematic Reviews. The general methods for these meta-analyses are outlined. Results: The DREAM database includes 1623 RCTs (4359 comparisons), of which 44% (707/1623) were placebo-controlled, 70% (1141/1623) had parallel-group allocation, and 37% (607/1623) had 3 or more randomized groups. A total of 304,253 participants (mean age 54 years; 509/1623, 46% female) were included, 86% (1391/1623) of RCTs had participants with hypertension, and 11% (175/1623) of RCTs had participants with cardiovascular disease at baseline. RCTs with at least 1 group randomized to combination therapy accounted for 23%(371/1623). The median duration of treatment was 8 weeks. Most (93%, 1509/1623) RCTs reported data on effects on blood pressure. Conclusions: Thefirst series of meta-analyses using the DREAM database will assess the effects of antihypertensive medicines on blood pressure and safety outcomes, including effects on headache, and cardiovascular events. The findings of these meta-analyses will inform clinical practice guidelines and help identify priorities for future research. International Registered Report Identifier (IRRID): DERR1-10.2196/65205