Abstract
Purpose::
To evaluate the role of intraocular pressure (IOP) reduction and other inter-current factors on the development of open angle glaucoma (OAG) in ocular hypertensive patients enrolled in the European Glaucoma Prevention Study (EGPS).
Methods::
The EGPS is a randomized, double masked, controlled clinical trial. 1077 patients (age => than 30 years) were enrolled by 18 European centers. The patients fulfilled a series of inclusion criteria, including IOP of 22-29 mmHg; two normal and reliable visual fields and normal optic discs as determined by an Optic Disc Reading Center. Patients were assigned to treatment with dorzolamide or placebo in one or both eyes. Efficacy end points were visual field and/or optic disc changes. Clinical data, including information about the use of any topical or systemic drugs, were collected every 6 months during follow-up. All randomized patients were included in the analysis and patients who were lost to follow-up or reached a safety end point were considered censored at the time of loss to follow-up or reaching the safety end point. Proportional hazards models were used to identify factors that occurred during follow up (inter-current factors), that were associated with the development of OAG.
Results::
Median duration of follow-up was 55.3 months. 106 patients reached an efficacy end point. In multivariate analyses, adjusting for treatment arms and baseline predictive factors, the following inter-current factors were associated with the development of OAG: mean follow-up IOP reduction (hazard ratio (HR) 0.89, 95% confidence intervals (CI) 0.80-0.98), mean follow-up IOP (HR 1.12, 95% CI 1.02-1.22), area under the curve of IOP (mmHg per year) (HR 1.09, 95% CI 1.05-1.12), disc hemorrhages (HR 1.83, 95% CI 1.15-2.92), and the use of systemic diuretics (HR 2.48, 95% CI 1.13-5.44). All baseline predictive factors previously identified except for age remained statistically significant.
Conclusions::
These results suggest that IOP reduction during follow-up, obtained by dorzolamide and/or placebo, was protective from development of OAG in the EGPS. They confirm the importance of disc hemorrhages, and support the need for future investigations to better elucidate the role of systemic diuretics in the development of OAG.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • intraocular pressure • clinical (human) or epidemiologic studies: risk factor assessment