Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event

addresses: Peninsula College of Medicine and Dentistry, St Luke's Campus, University of Exeter, Exeter, UK. [email protected]: PMCID: PMC3528446types: Journal Article; Research Support, Non-U.S. Gov't© 2012 Warren et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention

Has the controversy over the use of calcium channel blockers in coronary artery disease been resolved?

Calcium channel blockers are used in the treatment of hypertension and angina. The negative findings on cardiovascular outcomes with some short-acting formulations of calcium channel blockers, described in the 1990s, have led to a much reduced use of calcium channel blockers in general. A Coronary disease Trial Investigating Outcome with Nifedipine (ACTION) investigated the effects of the long-acting gastrointestinal therapeutic system (GITS) formulation of nifedipine in patients with stable symptomatic coronary artery disease. There was less new overt heart failure in the nifedipine GITS group (117 of 3825 patients) than in the placebo group (158 of 3840), and coronary angiography and coronary bypass surgery were also lower in the nifedipine GITS than placebo group. Peripheral revascularisation was slightly higher in the nifedipine GITS (187/3825) than the placebo group (144/3840). The Comparison of Amlodipine versus Enalapril to Limit Occurrences of Thrombosis (CAMELOT) trial compared a calcium channel blocker (amlodipine) and angiotensin-converting enzyme inhibitor (enalapril) in normotensive patients with coronary artery disease. The primary outcome of cardiovascular events occurred in 151 (23.1%), 110 (16.6%) and 136 (20.2%) of placebo, amlodipine and enalapril patients, respectively, with the only significant difference being a reduction with amlodipine compared with placebo. This reduction mainly represented a reduction in coronary revascularisation and hospitalisation for angina with amlodipine compared with placebo. These results suggest that calcium channel blockers are safe and beneficial in the treatment of coronary artery disease