Validating and updating the OHTS-EGPS model predicting 5-year glaucoma risk among patients with ocular hypertension using electronic medical records: a cohort study

Background: Ocular hypertension, that is intraocular pressure > 21 mmHg, is a risk factor for glaucoma. A glaucoma risk predictor, the Ocular Hypertension Study-European Glaucoma Prevention Study model, is available. Objectives: (1) To validate and update the Ocular Hypertension Study-European Glaucoma Prevention Study risk prediction model in a United Kingdom population; (2) to assess the relative efficiency of alternative monitoring pathways according to glaucoma risk; (3) to determine the clinical and cost-effectiveness of treating people with ocular hypertension with intraocular pressure of 22 or 23 mmHg and (4) to elicit patient preferences for monitoring. Design: (1) Retrospective data analysis of electronic medical records of ocular hypertension patients attending hospital eye services. The influence of the Ocular Hypertension Study-European Glaucoma Prevention Study predictors and additional ocular and systematic factors was explored. Validation: the Ocular Hypertension Study-European Glaucoma Prevention Study prediction model was applied. Update: the model was refitted by re-estimating baseline hazard and regression coefficients. (2, 3) Predictor versus standard care, with deterministic and probabilistic sensitivity analyses. Subgroup analysis for people with 22-23 mmHg intraocular pressure. (4) Discrete choice experiment. Setting and participants: People with intraocular pressure 22-32 mmHg in either eye, at least four visual field tests, 5 years of follow-up, no significant ocular comorbidities. Data sourced from secondary clinical settings. Main outcome measures: Discriminative ability (c-index) and calibration (calibration slope) to predict conversion to glaucoma in 5 years. Quality-adjusted life-years, incremental cost-effectiveness ratio, preferences. Data sources: Electronic medical records of 10 hospitals in England. Results: (1) Of 9030 patients with ocular hypertension who fitted the inclusion criteria 1530 (16.9%) converted to glaucoma. The Ocular Hypertension Study-European Glaucoma Prevention Study model provided a pooled c-index of 0.61 (95% confidence interval: 0.60 to 0.63). The updated model had a pooled c-index of 0.67 (0.51 to 0.84). (2) In the economic model almost all (99%) patients were treated in the risk predictor strategy, and less than half (47%) in the standard care strategy. The risk predictor strategy produced higher costs, but also higher quality-adjusted life-years and is likely to be cost-effective compared with standard care. (3) Patients with ocular hypertension and intraocular pressure 22-23 mmHg had similar risk of conversion to the rest of the cohort. A treat-all strategy may not be cost-effective. (4) Three hundred and sixty patients were recruited from four NHS hospitals. Almost all respondents (92%) had experienced face-to-face monitoring at a hospital; fewer respondents had experienced virtual clinics (47%) or community optometrist monitoring (43%). Most patients preferred hospital-based monitoring services by health professionals rather than community-based by optometrists but patients with prior experience of community optometrist monitoring preferred it. Patients preferred options associated with lower risk of conversion and lower costs. Limitations: Insufficient data to evaluate influence of ethnicity or ocular factors such as optic disc and retinal anatomy. Conclusions: We validated the Ocular Hypertension Study-European Glaucoma Prevention Study predictor model in a large population with ocular hypertension achieving modest improvements. The use of a risk prediction tool is likely to be cost-effective. Reducing the risk of conversion was the most important preference for patients with ocular hypertension. Future work: Future work should address the influence of genetic or other ocular factors in disease progression, evaluation of effectiveness and cost-effectiveness of different models of eye care, and on how to avoid late glaucoma presentation.

Citation

Wright, D., Wu, H., King, A., Montesano, G., Higgins, B., Gazzard, G., Morgan, J., McNaught, A., Sebastian, R., Ahmed, F., Dimitriou, C., Nagar, M., Scott, A., Rafiq, O., Harper, R., Crabb, D., Watson, V., Hernández, R., Cardwell, C., Takwoingi, Y., … Azuara-Blanco, A. (2026). Validating and updating the OHTS-EGPS model predicting 5-year glaucoma risk among patients with ocular hypertension using electronic medical records: a cohort study. Health technology assessment (Winchester, England), 30(25), 1–35. https://doi.org/10.3310/GJAA0514

DOI

10.3310/GJAA0514

URI

https://hdl.handle.net/20.500.14709/1443

License

CC BY 4.0

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CC BY 4.0

License

https://creativecommons.org/licenses/by/4.0/