Screening for open angle glaucoma: a systematic review of cost-effectiveness studies

Methodological quality of the review: Low confidence

Author: Hernández R, Rabindranath K, Fraser C, Vale L, Blanco AA, Burr JM; OAG Screening Project Group

Geographical coverage: United States of America (USA), Canada, United Kingdom (UK)

Sector: Glaucoma

Sub-sector: Open angle glaucoma

Equity focus: Studies in adult population

Review type: Other review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background: Population screening for open angle glaucoma (OAG) could be considered as an intervention to reduce blindness by identifying individuals at an earlier stage of the disease. Due to limited healthcare resources, it is important to assess the cost-effectiveness of screening for OAG.

Objectives:  To systematically review current evidence on the cost-effectiveness of screening strategies for open angle glaucoma.

Main findings: Only four studies were found to be eligible in this review, with the most recent published in 1997. All four studies assessed the cost-effectiveness of screening for primary OAG. One study each was conducted in Canada and the USA, and two studies were from the UK.

Authors note that the screening tests and treatments reported in these studies are now not considered to be best practice. In addition, authors stated that it was not possible to reinterpret the results of the studies in terms of a common outcome measure as there was no sufficient data reported. Based on this review, authors concluded that there is no sufficient economic evidence on which recommendations regarding screening for OAG can be based.

According to review authors, future studies for economic models and clinical trials – and using the most recent technologies – may help policymakers to identify the most cost-effective screening methods.

Methodology: The following databases were searched for relevant articles written in English: MEDLINE (1966-November Week 3 2005); EMBASE (1980-2005 Week 49); MEDLINE In Process & Non-indexed Citations (23rd February, 6th December 2005); Science Citation Index (SCI) (1981-3rd December 2005); NHS Economic Evaluation Database (NEED) (November 2005); Health Technology Assessment Database (HTA Database) (November 2005); Health Management Information Consortium (HMIC) (November 2005). Authors performed general searches within reviews.

The following studies were included: studies performed in adult populations – including any intervention for OAG screening – and comparing both costs and outcomes.

Studies that did not relate cost to outcome data, methodological papers, papers which reviewed economic evaluations, discursive analysis of costs/benefits, partial evaluation studies such as cost analyses, efficacy, or effectiveness evaluations and cost of treatment/burden of illness papers were excluded.

Critical appraisal and data extraction were, according to the Centre for Reviews and Dissemination, for the critical appraisal of economic evaluations guidelines. Data was extracted by one reviewer and checked by a second reviewer. The two main areas of data extraction were the results of the economic evaluations (estimates of costs and effects) and the methods used to derive the results and their interpretation. Extracted data was summarised but no quantitative analysis was conducted.

Applicability/external validity: Authors state that the outcome of this study is not relevant for policymakers as it suffers from many limitations. Authors note that none of the studies implicitly stated why the chosen strategies were appropriate settings, making it hard to judge if these are relevant strategies for other settings. In addition, authors state that different country reimbursement strategies and costs could complicate the interpretation of results, as they may not be applicable to other countries owing to differences in their economies or the way health services are organised (e.g. UK-based study from a US perspective).

Geographic focus: Studies included were from the USA, UK and Canada.

Summary of quality assessment: This review was based on relevant database searches. However, reference lists were not searched for additional articles and experts were not consulted. Furthermore, there was a language restriction as only English articles were looked at. Therefore, we could not be confident that relevant literature was not omitted.

In addition, it is unclear whether two researchers independently participated in the screening. Data was extracted by one reviewer only. Overall, based on the information provided in the review, low confidence was attributed in the conclusions about the effects of this study.