Diabetic Retinopathy (treatment)

Methodological quality of the review: Medium confidence

Author: Mohamed QA, Ross A, Chu CJ.

Region: Details not provided

Sector: Diabetic retinopathy

Sub-sector: Laser photocoagulation, intravitreal triamcinolone acetonide, anti-VEGF , vitrectomy.

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis methods: Not applicable

Background

Diabetic retinopathy (DR) can cause microaneurysms, haemorrhages, exudates, changes to blood vessels and retinal thickening. There are a number of interventions for treating diabetic retinopathy including laser and drug treatments.

Research objectives

To answer the following clinical questions: what are the effects of treatments in people with diabetic retinopathy? What are the effects of treatments for vitreous haemorrhage?

Main findings

The authors include 58 systematic reviews, RCTs or observational studies in the review which assessed the effects, benefits and harms of treatments in people with DR. The geographical location of the reviews was not reported. Review authors presented findings on the effectiveness and safety of the following interventions: (1) Peripheral retinal laser photocoagulation reduces the risk of severe visual loss compared with no treatment in people with preproliferative retinopathy and maculopathy. (2) The benefits of laser photocoagulation are more notable in people with proliferative retinopathy than in those with maculopathy. (3) Intravitreal triamcinolone acetonide improves visual acuity and reduces macular thickness in eyes with macular oedema refractory to previous macular laser photocoagulation, but repeated injections are needed to maintain benefit. (4) VEGF inhibitors pegaptanib and bevacizumab improve visual acuity and reduce macular thickness in eyes with centre-involving diabetic macular oedema and vision loss, but repeat intravitreal injections are needed to maintain benefit. (5)Vitrectomy can reduce visual loss if performed early in people with vitreous haemorrhage, especially if they have severe proliferative retinopathy.

Methodology

Authors searched MEDLINE (1966 to June 2010), EMBASE (1980 to June 2010) and the Cochrane Database of Systematic Reviews (1966 to date of issue). An additional search within The Cochrane Library was conducted for the Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA).The authors also searched for retractions of studies included in the review.

The study design criteria for inclusion were: published systematic reviews of RCTs and RCTs in any language, at least single blinded, and containing more than 20 individuals of whom  more than 80% were followed up. There was no minimum length of follow up required. In addition, surveillance protocols were used to capture harms alerts from organizations.

To evaluate the quality of the evidence the authors used a GRADE tool. The categorization of the quality of the evidence consisted of high, moderate, low or very low.

The main measurement outcome was visual acuity measured using a Snellen chart; incidence of visual disability, partial sight registration and registrable blindness.

Applicability/external validity

The authors did not specifically discuss the external validity of the results.

Geographic focus

Authors did not report geographic focus of included studies.

Quality Assessment

Authors searched MEDLINE (1966 to June 2010), EMBASE (1980 to June 2010) and the Cochrane Database of Systematic Reviews (1966 to date of issue). No language restrictions were applied. It was not clear if references lists of the included studies were checked and if study authors were contacted as part of the search strategy.

Abstracts of the studies retrieved from the initial search were assessed by an information specialist and selected studies were then sent to the contributor for further assessment. It was not clear if independent data extraction was conducted by at least two reviewers. There was some reporting on reviews’ methods of analysis but it lacked clarity. As such, medium confidence was attributed in the conclusions about the effects of this study.