Background There are more than one million National Health Service visits in England and Wales each year for patients with glaucoma or ocular hypertension (OHT). With the ageing population and an increase in optometric testing, the economic burden of glaucoma-related visits is predicted to increase. We examined the conversion rates of OHT to primary open-angle glaucoma (POAG) in England and assessed factors associated with risk of conversion.
Methods Electronic medical records of 45 309 patients from five regionally different glaucoma clinics in England were retrospectively examined. Conversion to POAG from OHT was defined by deterioration in visual field (two consecutive tests classified as stage 1 or worse as per the glaucoma staging system 2). Cox proportional hazards models were used to examine factors (age, sex, treatment status and baseline intraocular pressure (IOP)) associated with conversion.
Results The cumulative risk of conversion to POAG was 17.5% (95% CI 15.4% to 19.6%) at 5 years. Older age (HR 1.35 per decade, 95% CI 1.22 to 1.50, p<0.001) was associated with a higher risk of conversion. IOP-lowering therapy (HR 0.45, 95% CI 0.35 to 0.57, p<0.001) was associated with a lower risk of conversion. Predicted 5-year conversion rates for treated and untreated groups were 14.0% and 26.9%, respectively.
Conclusion Less than one-fifth of OHT patients managed in glaucoma clinics in the UK converted to POAG over a 5-year period, suggesting many patients may require less intensive follow-up. Our study provides real-world evidence for the efficacy of current management (including IOP-lowering treatment) at reducing risk of conversion.
- intraocular pressure
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Contributors SRK contributed to the design and implementation of the research, to the statistical analysis of the results and to the writing of the manuscript. APK contributed to the design and implementation of the research and to the writing of the manuscript. SRB contributed to the design and implementation of the research and to the writing of the manuscript. AA-B contributed to the design and implementation of the research and to the writing of the manuscript. JMS contributed to the design and implementation of the research and to the writing of the manuscript. DPC contributed to the design and implementation of the research, to the writing of the manuscript. and supervised the project. All authors discussed the results and contributed to the final manuscript.
Funding SRK received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 675033. APK is supported by a Moorfields Eye Charity Career Development Fellowship. JMS is clinical lead for the HQIP commissioned National Ophthalmology Audit.
Disclaimer The listed funding organisations had no role in the design or conduct of this research.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The current study was undertaken through a data-sharing agreement and adhered to the Declaration of Helsinki with all analyses approved by a research ethics committee of City, University of London.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.
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