Eliciting preferences in glaucoma management-a systematic review of stated-preference studies

Author: Scheres LM, Hiligsmann M, van Gorcom L, Essers BAB, Beckers HJM.

Geographical coverage: Australia, Germany, Singapore, United Kingdom (UK), and United States of America (USA).

Sector: Service delivery

Sub-sector: Quality of healthcare services

Equity focus: Not explicitly stated

Study population: Patients with glaucoma

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background

Glaucoma is a leading cause of irreversible and preventable blindness globally. It is characterised by progressive optic nerve damage and visual field loss. The primary treatment aim is to lower intraocular pressure (IOP) using medical therapy, laser procedures, or surgery. Minimally invasive glaucoma surgeries (MIGS) have improved treatment with better safety and recovery times. However, their effectiveness in lowering IOP is less favourable compared to traditional filtering surgery. Healthcare providers typically assess glaucoma management based on clinical measures like IOP reduction and visual field stability, but patient preferences and quality-of-life factors are increasingly valued in treatment decisions. Factors such as side effects, affordability, treatment burden and recovery time substantially influence patient choices, yet these remain underexplored in clinical practice. Stated-preference studies offer a method to quantify how patients and healthcare professionals value different aspects of glaucoma care, facilitating more patient-centred decision-making.

Objectives

To systematically review and critically appraise stated-preference studies in glaucoma management to identify the most valued attributes by patients and healthcare professionals and provide insights into patient preferences for improving patient-centred care.

Main findings

Overall, the findings of the review suggest that patients had preferences and were willing to trade-off between different attributes. The outcome characteristics were the most influential in the management of glaucoma.

The review included 11 studies published between 2005 and 2021, conducted in high-income countries, with sample sizes ranging from 32 to 500 participants. Most studies (91%) focused on patient preferences, while one study (9%) examined ophthalmologists’ preferences. The studies explored preferences in three main areas: glaucoma treatment (n=3), assessing trade-offs between benefits, risks, and treatment characteristics; glaucoma-related health state valuation (n=4), understanding patient priorities for quality of life and functional outcomes; and glaucoma service preferences (n=4), evaluating patient priorities in follow-up care, diagnostics, and service delivery. A total of 69 attributes were identified, of which 43 (62%) were categorised as outcome attributes, 22 (32%) as process attributes, and 4 (6%) as cost attributes. Outcome attributes, particularly effectiveness, were the most influential in decision-making.

The studies were evaluated using the Purpose, Respondents, Explanation, Findings, Significance (PREFS) checklist and International Society for Pharmacoeconomics and Outcomes Research (ISPOR) checklists. Most studies scored 4 out of 5 on the PREFS checklist, with one study scoring 5/5 and two scoring 3/5. The ISPOR checklist showed scores ranging from 22 to 29 out of 30, indicating generally good quality but highlighting weaknesses in instrument design, data collection, and statistical analysis reporting. The most common methods for attribute and level identification and selection were expert consultation (81%), followed by literature review (55%), qualitative interviews (36%), and focus groups (27%).

Methodology

The authors conducted a search in PubMed and Embase databases on 27th October 2021 for stated-preference studies that investigated patient and healthcare provider preferences for different aspects of glaucoma management and were published in English. Additionally, a backward and forward reference search strategy using Web of Science was performed on the included studies.

Two reviewers independently screened the relevant articles against the eligibility criteria, resolving any disagreements through discussion or by consulting a third reviewer. Study quality was assessed using the PREFS checklist, evaluating five criteria: Purpose, Respondents, Explanation, Findings, and Significance. The reviewers independently assessed the quality of the studies and resolved disagreements through discussion.

Data on attributes were extracted and categorised into three main categories: outcome, process, and cost. These categories were further divided into subcategories for attributes with common characteristics (such as effectiveness and adverse effects for the outcome category), facilitating a comprehensive synthesis of results. The relative importance of attributes was evaluated using reported values or calculated using the range method recommended by ISPOR (International Society for Pharmacoeconomics and Outcomes Research).

Applicability/external validity

The review acknowledged limitations in the external validity of its findings due to variability in study design, patient populations, and healthcare settings. It emphasised that preferences were context-dependent, influenced by factors such as disease severity and geographic differences. While the findings provided valuable insights for patient-centred care, their generalisability remains limited. This necessitates further research to enhance applicability across diverse populations.

Geographic focus

Included studies were conducted in Australia, Germany, Singapore, United Kingdom (UK), and United States of America (USA).

Summary of quality assessment

The authors did not check reference lists or consult experts during the search. They failed to provide a list of excluded studies, and did not specify the number of reviewers for data extraction. Although study quality was assessed, findings were not distinguished by risk of bias.