TY - JOUR
AU - Williams, I M
AB - Sir We would like to thank Bailey and colleagues for their interesting comments. Meta-analysis is only as good as the studies involved. When examining statins and abdominal aortic aneurysm (AAA), all available studies were retrospective. Results were therefore subject to the usual statistical constraints. Newcastle–Ottawa scoring, random-effects models and funnel plots were all used in an attempt to offset these constraints1. As mentioned, the effect of meta-analysing different methods of growth expansion measurement is unclear. However, the results from the large, high-quality studies were so similar (Fig. 2) that even re-analysing the primary data for consistency was unlikely to lead to a different outcome. Medication compliance is one of a number of confounding factors in clinical studies. It is a complex issue that is notoriously difficult to measure reliably, even in randomized controlled trials2,3. The Newcastle–Ottawa score includes up to two stars for adjustment for confounding factors, which were achieved by all of the high-quality studies included in the AAA expansion analysis. Adjusting for factors with a known impact on vascular disease is arguably more important than attempting to control for the nebulous effect of medication compliance, and for this reason it was not addressed. We absolutely agree that to reach firm conclusions on the role of any intervention on AAA growth rates, it is essential that a consistent, realistic measure of AAA growth is used and patients are followed up meticulously. However, until such studies arise, and within the context of our results, statins do not appear to influence AAA expansion rates. References 1 Higgins JPT , Green S. Cochrane Handbook for Systematic Reviews of Interventions, version 5.0.2 . The Cochrane Collaboration, 2009 ; http://www.cochrane-handbook.org [accessed 25 February 2011]. 2 Hughes D , Cowell W, Koncz T, Cramer J; International Society for Pharmacoeconomics and Outcomes Research Economics of Medication Compliance Working Group . Methods for integrating medication compliance and persistence in pharmacoeconomic evaluations . Value Health 2007 ; 10 : 498 – 509 . Google Scholar Crossref Search ADS PubMed WorldCat 3 Schedlbauer A , Davies P, Fahey T. Interventions to improve adherence to lipid lowering medication . Cochrane Database Syst Rev 2010 ; ( 4 ) CD004371 . Google Scholar OpenURL Placeholder Text WorldCat Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
TI - Authors' reply: Systematic review and meta-analysis of the effects of statin therapy on abdominal aortic aneurysms (Br J Surg 2011; 98: 362–353)
JO - British Journal of Surgery
DO - 10.1002/bjs.7513
DA - 2011-04-01
UR - https://www.deepdyve.com/lp/oxford-university-press/authors-reply-systematic-review-and-meta-analysis-of-the-effects-of-eajWwiJqNp
SP - 745
EP - 745
VL - 98
IS - 5
DP - DeepDyve
ER -