Methodological quality of the review: Medium confidence

Author: Kymes SM, Burk C, Feinman T, Williams JM, Hollander DA

Geographical coverage: Turkey and Brazil as well as upper/middle-income settings

Sector: Glaucoma and ocular hypertension

Sub-sector: Evidence-based decision

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background: There is a need for an easy and fast tool to systematically assess the efficacy of topical prostaglandin analogues in reducing intra-ocular pressure (IOP) in glaucoma and ocular hypertension, as traditional systematic reviews and meta-analysis consume too much time and effort, and quickly become out-of-date

Objectives: To demonstrate the use of an online service for conducting a systematic review and meta-analysis of the efficacy of topical prostaglandin analogues in reducing IOP in glaucoma and ocular hypertension.

Main findings: In this meta-analysis, 16 studies were eligible. The impact of bimatoprost on lowering IOP relatively greater than latanoprost (1 mm Hg, P = 0.025) and travoprost (0.8 mm Hg, P = 0.033) based on mean IOP after 12-26 weeks of treatment. There was no statistical difference in IOP-lowering between latanoprost and travoprost (P = 0.841). Findings of this study were similar to previously published meta-analyses of topical prostaglandin analogues.

The authors conclude that systematic reviews based on meta-analysis are considered the “gold standard” for synthesising evidence to support clinical decision-making. However, it is time-consuming, labour intensive and outside the capability of most formulary managers. The effectiveness of a commercial service that facilitates the process of conducting such reviews was demonstrated.

Methodology: To identify relevant studies via a service provider, the following databases were searched: Cochrane Library (CDSR, CENTRAL, DARE), MEDLINE and published systematic reviews. The following search terms were used: glaucoma, primary, open angle, POAG, intra-ocular pressure, ocular, eye, pressure, hypertension, hypertensive, IOP, normotensive, normal tension, low tension, bimatoprost, Lumigan, latanoprost, Xalatan, travoprost, Travatan, prostaglandin analogues and visual field. The search was up to September 2009.

RCTs with at least two interventions and published in English were included. Standard methods were used for identifying, abstracting and analysing findings of papers. The inverse variance method of weighting data for pooling was used for meta-analyses. The Cochrane Q chi-square test was used to test heterogeneity of results across studies.

Applicability/external validity: This was not discussed but authors suggested that the online service may be a valuable tool for conducting systematic reviews and meta-analysis that could be helpful for decision making.

Geographic focus: The review doesn’t focus specifically on low/middle-income countries, though the results might be applicable to low/middle-income settings.

Summary of quality assessment: The systematic review was based on a comprehensive search of the literature. Although no date restriction was applied, language and selection bias was not avoided. Screening of full text and data extraction was appropriately conducted by the authors. Heterogeneity between the included studies was assessed. The criteria for assessing the quality of included studies are not clear. Therefore, medium confidence was attributed in the conclusions about the effects of this study.