Meta-analysis of well-designed nonrandomized comparative studies of surgical procedures is as good as randomized controlled trials

Abraham, Ned S.; Byrne, Christopher J.; Young, Jane M.; Solomon, Michael J.

doi:10.1016/j.jclinepi.2009.04.005

« Previous Next »Journal of Clinical Epidemiology
Volume 63, Issue 3 , Pages 238-245, March 2010

Meta-analysis of well-designed nonrandomized comparative studies of surgical procedures is as good as randomized controlled trials

Ned S. Abraham
- Faculty of Medicine, The Coffs Harbour Health Campus, The University of New South Wales, Coffs Harbour, NSW, Australia
- The Surgical Outcomes Research Centre (SOuRCe), Sydney South West Area Health Service, The University of Sydney, Sydney, Australia
- Corresponding author. Coffs Harbour Campus, Faculty of Medicine, University of New South Wales, POB 2244, Coffs Harbour, NSW 2450, Australia. Tel: +612-6652-0411; fax: +612-6652-0400.
Christopher J. Byrne
- The Surgical Outcomes Research Centre (SOuRCe), Sydney South West Area Health Service, The University of Sydney, Sydney, Australia
- Department of Colorectal Surgery, Royal Prince Alfred Hospital, Sydney, Australia
Jane M. Young
- The Surgical Outcomes Research Centre (SOuRCe), Sydney South West Area Health Service, The University of Sydney, Sydney, Australia
- Department of Colorectal Surgery, Royal Prince Alfred Hospital, Sydney, Australia
Michael J. Solomon
- The Surgical Outcomes Research Centre (SOuRCe), Sydney South West Area Health Service, The University of Sydney, Sydney, Australia
- Department of Colorectal Surgery, Royal Prince Alfred Hospital, Sydney, Australia

Accepted 17 April 2009. published online 28 August 2009.

Abstract

Objective

To compare the results of meta-analysis of nonrandomized comparative studies (NRCSs) of a surgical procedure with that of randomized controlled trials (RCTs), and to assess the effect of design and conduct issues in NRCSs on measured outcomes.

Study Design and Setting

Two meta-analyses of RCTs and NRCSs (2,512 and 6,438 procedures, respectively) of laparoscopic resection for colorectal cancer were performed according to accepted protocols, and 13 outcomes common between them were compared. Odds ratios (ORs) and 95% confidence intervals (CI) for dichotomous outcomes were assessed for the degree of overlap. Continuous outcomes were compared using cumulative weighted ratios (CWRs) and percentages for which a mean and standard deviation (SD) were calculated. The effects of design and conduct issues in the meta-analysis of NRCSs on measured morbidity rates were assessed using subgroup analysis.

Results

The ORs of the three dichotomous outcomes overlapped widely. For the 10 continuous variables, the mean difference (SD) in the results of the two meta-analyses was only 5.6% (4.9%). Fulfillment of certain quality and conduct issues in the NRCSs determined the statistical homogeneity of the results of meta-analysis and their comparability with the “gold standard.”