Efficacy and economic analysis of Ex-PRESS implantation versus trabeculectomy in uncontrolled glaucoma

Methodological quality of the review: High Confidence

Authors: Wang L, Sha F, Guo DD, Bi HS, Si JK, Du YX, Tang K

Region: USA, Canada, South Africa, Japan, Spain, Netherlands

Sector: Glaucoma

Sub-sector: Treatment

Equity focus:  None specified

Review type: Other review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background:

Traditionally, trabeculectomy (Trab) is considered the gold standard in the glaucoma surgery. However, there were some postoperative complications including hypotony, choroidal detachment, bleb leak and encapsulated bleb, and more drugs or additional surgeries may be needed post operation, so it will further increase the total cost. Consequently, it is essential to create a better and safer operation. The Ex-PRESS glaucoma filtration implantation was developed as an alternative to Trab. It is a small, stainless and non-valved flow-restricting device. To evaluate whether Ex-PRESS offers any advantages for medically uncontrolled glaucoma in terms of efficacy and fewer postoperative complications with lower cost, the authors undertook a systematic review on economic analysis and meta-analysis on efficacy and safety for Ex-PRESS and Trab.

Objectives:

To systematically review the current evidence based on the efficacy and cost of Ex -PRESS implantation and trabeculectomy (Trab) for uncontrolled glaucoma.

Main findings:

Ten studies were used to analyse the efficacy and safety for Ex-PRESS and Trab. Therefore, a total of 769 eyes from 739 patients were included in the present meta-analysis. The authors further estimated the cost difference between two operations using a systematic review, which involved one article and two abstracts. Among the 10 included studies, there were four randomized controlled trial (RCT) studies, four retrospective studies, and two prospective studies. For geographic distribution, five studies were carried out in USA, one in Spain, one in the Netherlands, one in Japan, one in South Africa, and one in Canada.

The efficacy of Ex-PRESS was similar to that of Trab in the percentage of IOP reduction (IOPR %) at 1, 2y (weighted mean difference (WMD): -2.01; 95% confidence interval (CI): -7.92-3.90; =0.50 and WMD: 2.89; 95%CI: -8.05-13.83; =0.60, respectively). Ex-PRESS possessed a significant higher complete and qualified success rate (OR: 1.59; 95% CI: 1.07-2.35; =0.02 and OR: 1.74; 95% CI: 1.06-2.86; =0.03, respectively). Moreover, Ex -PRESS exerted a significantly lower frequency of hypotony and hyphema than Trab (OR: 0.39; 95% CI: 0.21-0.72; =0.003 and OR:0.27; 95% CI: 0.10-0.69; =0.003, respectively). However, there was no consistent result on the cost between the two groups according to the previous three studies.

Both Trab and Ex -PRESS have equivalent efficacy in lowering IOP, yet Ex-PRESS had a lower risk of hypotony and hyphema than Trab. Nevertheless, whether the cost of Ex -PRESS was less than that of Trab should be further investigated to ensure evidence-based conclusion in the long run.

The results should be considered with cautions because of the limitation (language limitation, publication bias, difference in study quality and different durations). Despite the limitations, the authors believe that the results of the current meta-analysis study are clinically useful for glaucoma treatment. To draw an accurate conclusion, more RCTs with larger sample sizes or systematic studies are urgently needed to better evaluate the long-term benefits and cost-effectiveness both for Ex-PRESS and Trab.

Methodology:

Clinical trials were identified by electronic databases (PubMed, EMBASE, ISI Web of science and Cochrane library), and data, such as intraocular pressure (IOP), the complete and qualified success rate, the postoperative complications and the cost, were exacted from these relevant studies. Weighted mean difference (WMD), odds ratio (OR) and 95% confidence intervals (CIs) were calculated and were pooled using a random effects model.

Applicability/external validity:

Although the Ex-PRESS shunt is gaining popularity, the authors found no complete consistence with the type of glaucoma for the use of the Ex-PRESS implantation, and reports concerning the relative efficacy and safety of Ex-PRESS and Trab are controversial. The implantation of Ex-PRESS shunt possesses a markedly higher cost and might be a major limitation in its adoption into clinical practice, especially in developing countries. In view of this point, it is necessary to inform the glaucoma patients about the cost-effectiveness and voluntary choice of the Ex-PRESS. Nevertheless, further studies should be done to evaluate cost effectiveness to allow optimal choice of glaucoma surgery.

Geographic focus: The authors did not report applicability of findings to low- and middle-income countries.

Summary of quality assessment:

The authors met each of the criteria except that they only included published studies. Despite this they do explain at length the various limitations of the meta-analysis and where they recommend further research and analysis. For this reason, they have been awarded High Confidence.