Prospective, randomized, open-label, blinded-endpoint (PROBE) designed trials yield the same results as double-blind, placebo-controlled trials with respect to ABPM measurements

Objective This meta-analysis aimed to determine whether ambulatory blood pressure monitoring (ABPM) results from double-blind, placebo-controlled (DBPC) and prospective, randomized, open-label, blinded-endpoint (PROBE) hypertension trials are statistically comparable. Methods Two DBPC and three PROBE parallel-group studies were selected from an angiotensin II receptor blocker clinical programme. These were fixed-dose studies involving similar mild to moderate hypertensive patient populations. All used SpaceLabs 90207 ABPM devices, and each comprised a 4-week placebo period and a 4-8-week treatment period. Data from patients receiving telmisartan 80 mg were used to compare the results of DBPC (126 patients) and PROBE (734 patients) trials. The analysis had approximately 87% power to show equivalence between the two design types in terms of ruling out differences of greater than or equal to 3 mmHg in SBP and greater than or equal to 2 mmHg in DBP. Off ice blood pressure was also compared. Results The change from baseline in mean 24-h ambulatory SBP was -12.2 mmHg in DBPC trials and - 12.3 mmHg in PROBE trials, a rounded difference of 0.2 mmHg [95% confidence interval (Cl): -1.8,2.1]. The change from baseline in mean 24-h ambulatory IDBP was - 7.7 mmHg in DBPC trials versus -7.9 mmHg in PROBE trials, a difference of 0.2 mmHg (95% Cl: -1.1, 1.5). Ambulatory pulse pressure results were identical. Conclusions Thus, changes in mean 24-h ambulatory blood pressure from the DBPC and PROBE trials in this meta-analysis are statistically equivalent in terms of ruling out a difference of greater than or equal to 3 mmHg in SBP and greater than or equal to 2 mmHg in DBP. This supports the validity of the PROBE design in assessing antihypertensive efficacy based on blinded ABPM measurements.