Healthy Skepticism Library item: 5301

Warning: This library includes all items relevant to health product marketing that we are aware of regardless of quality. Often we do not agree with all or part of the contents.

Publication type: Journal Article

Smith DH, Neutel JM, Lacourciere Y, Kempthorne-Rawson J.
Prospective, randomized, open-label, blinded-endpoint (PROBE) designed trials yield the same results as double-blind, placebo-controlled trials with respect to ABPM measurements.
J Hypertens 2003 Jul 01; 21:(7):1291-8
http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0263-6352&volume=21&issue=7&spage=1291

Abstract:

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 >or= 3 mmHg in SBP and >or= 2 mmHg in DBP. Office 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 (CI): -1.8, 2.1]. The change from baseline in mean 24-h ambulatory DBP was -7.7 mmHg in DBPC trials versus -7.9 mmHg in PROBE trials, a difference of 0.2 mmHg (95% CI: -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 >or= 3 mmHg in SBP and >or= 2 mmHg in DBP. This supports the validity of the PROBE design in assessing antihypertensive efficacy based on blinded ABPM measurements.

Keywords:
Antihypertensive Agents/therapeutic use* Blood Pressure Monitoring, Ambulatory* Comparative Study Double-Blind Method Humans Hypertension/diagnosis* Hypertension/drug therapy* Placebos Prospective Studies Randomized Controlled Trials/methods* Randomized Controlled Trials/statistics & numerical data Research Support, Non-U.S. Gov't