Methodological quality of the review: Medium confidence

Author: Jones S, Edwards RT.

Region: Europe, North America

Sector: Diabetic retinopathy

Sub-sector: Economic evidence, cost effectiveness.

Equity focus: None specified

Review type: Effectiveness review

Quantitative synthesis method: Narrative analysis

Qualitative synthesis methods: Not applicable

Background

Diabetic retinopathy (DR) is a major complication of diabetes mellitus and is a leading cause of blindness. Screening for DR is possible and aims to detect early sight threatening lesions which can be treated with laser photocoagulation. Issues around cost effectiveness of ophthalmic care, systematic versus opportunistic screening, the delivery of DR services and that optimal screening internal continue to be debated. Debate around optimal screening intervals is particularly controversial.

Research objectives

‘To assess the economic evidence around diabetic retinopathy screening’.

Main findings

The review identified 21 studies for inclusion, of which 12 were cost-effectiveness studies, one was a cost analysis study, one a cost-minimization study, one a cost utility study and six were reviews. All studies offered evidence relating to the economic assessment of DR. All the studies cited were conducted in North America or Europe, although the geographical location for all the included studies was not reported. The authors reported the following results:

Systematic screening for DR in patients with diabetes is a more cost-effective intervention than opportunistic screening. The use of mobile screening (and a combination of mobile screening and other clinical settings) is cost-effective and an accessible way of delivering the programme to certain populations such as isolated communities. Digital photography with telemedicine links has the potential to deliver cost-effective, accessible screening to rural or hard- to-reach populations. Variation in compliance rates, age of onset of diabetes, glycemic control and screening sensitivities influence the cost-effectiveness of screening programme and are important sources of uncertainty in relation to the issue of optimal screening intervals.

Authors note that further research is needed to address the issue of optimal screening intervals.

Methodology

All studies included offered evidence relating to the economic assessment of diabetic retinopathy. Studies included people with type 1 and type 2 diabetes.

Authors conducted a search of a number of databases including British Medical Journal (BMJ) Archive, BIDS, MEDLINE, EMBASE, SIGLE, Dissertation abstracts as well as a number of websites and libraries. Only studies written in English were included in the review. It was not clear what dates were searched, although authors noted that studies were excluded if they were published before 1998. Two authors independently screened full text of potentially relevant studies for inclusion, extracted data and quality assessed included studies. Authors used a 10-item Drummond checklist for sound economic assessment to assess the quality of the wide range of studies included in the review.

Authors noted that meta-analysis was not possible in this instance, due to the diversity in research methods and interventions used by each study.

Applicability/external validity

External validity of the results was not explicitly reported in the review. The review largely relied upon economic modelling studies rather than primary research, which may limit the applicability of the results.

Geographic focus

European studies and North American studies were included in the review although it was not clear what other countries were included in the review in total.

Quality assessment

The review was based on searches of relevant databases, websites and a number of library catalogues, although language bias was not avoided as only studies written in English were included in the review. Appropriate methods were used to avoid risk of bias in terms of selection of studies, extraction of data and quality assess included studies. Methods used to analyse the findings were clear, but it should be noted that the review largely relied upon economic modelling studies rather than primary research, which may have limited the applicability of the results. As such, there is medium confidence in conclusions about the effects of this study.