Implications of blinding: quality of life in trials of revascularisation for chronic stable angina

Chronic stable angina is estimated to affect over 9 million adults in the USA (a prevalence of 3.6%). It has a considerable impact on quality of life (QoL). The issues of symptoms improvement and quality of life (QoL) are critical for the management of patients with chronic stable angina. As a matter of fact, the main aims of therapy are to reduce the risk of myocardial infarction and death but also to improve symptoms and QoL.
Conventional teaching, clinical experience, and unblinded trials tell us that revascularisation improves quality of life but this was not supported by the only blinded trial of PCI, ORBITA (Objective Randomised Blinded Investigation with Optimal Medical Therapy of Angioplasty in Stable Angina).
This article by AN Nowbar et al. (National Heart and Lung Institute, Imperial College London, London, UK) examines quality of life assessment in angina trials, the quality of life results of trials of percutaneous coronary intervention and coronary artery bypass grafting, and the impact of blinding.
Take-home message: Blinding might be expensive and difficult, but it is necessary. After ORBITA, another blinded trial, ORBITA-2, is underway and will add to the blinded data in the field.