Development of an Optimal Search Strategy for Finding Trials Demonstrating ACE Inhibitor Blood Pressure Lowering Efficacy

Article type
Authors
S Heran B, M Wright J
Abstract
Objectives: Since its introduction in 1994, the search strategy recommended by the Cochrane Collaboration (Cochrane highly sensitive search strategy) has been adopted for use by many reviewers for the retrieval of controlled trials from Medline using Ovid and SilverPlatter. Our objective was to evaluate whether a modified and expanded form of the Cochrane highly sensitive search strategy would identify additional RCTs in Medline that would meet the pre-specified inclusion criteria of our systematic review of the dose-related blood pressure lowering efficacy of ACE inhibitors in the treatment of primary hypertension.

Methods: A modified search strategy was developed based on the Cochrane highly sensitive search strategy. Both the original and modified form of the search strategy were implemented for the retrieval of RCTs from Medline using OVID. The number of RCTs retrieved that met the pre-specified inclusion criteria of our systematic review was compared between the Cochrane highly sensitive search strategy and the modified search strategy.

Results: The Cochrane highly sensitive search strategy identified 1361 references. The modified search strategy identified 1606 references. At the present time, of the additional 245 references identified by the modified search strategy, at least 5 additional RCTs have met our inclusion criteria and will be included in the systematic review.

Conclusions: Consistent with the Cochrane Reviewer's Handbook, increasing the comprehensiveness of our search has resulted in reduced precision. However, compared with Cochrane high sensitivity search strategy, our modified search strategy has identified at least 5 additional RCTs that have satisfied all criteria for inclusion in our systematic review. The additional data from these 5 trials will allow for a more precise estimate of the dose-related blood pressure lowering efficacy of ACE inhibitors in the treatment of primary hypertension. The modified search strategy will also be tested in four additional systematic reviews that are currently being conducted to quantify the dose-related blood pressure lowering efficacy of angiotensin receptor blockers, calcium channel blockers, beta blockers, and alpha blockers.