Topic Abstract

Background:

In the United States, the prevalence of open-angle glaucoma for all adults 40 years old and older is estimated to be 1.86%.¹ Open-angle glaucoma affects an estimated 2.22 million people, and that will rise to 3.3 million in 2020 as the population ages in the United States.² Glaucoma of all types is one of the leading causes of legal blindness in the country.^3,4 For primary open-angle glaucoma (POAG), race is an important risk factor. The prevalence of POAG is higher in individuals of West African, Afro-Caribbean, or Hispanic/Latino origin than in other groups.^{1, 5-9} Blindness from glaucoma is at least six times more prevalent in African Americans than in Caucasian Americans.⁴ Glaucoma is the leading cause of blindness in African Americans.

Objectives:

1. To compare the proportion of patients who achieve a successful response to treatment (reduction in IOP of >15%) between patients treated with laser surgery (including argon laser trabeculectomy, selective laser trabeculoplasty) with patients receiving additional medications, at 1-year post-treatment initiation
2. To compare the proportion of patients who achieve a successful response to treatment (reduction in IOP of >15%) between patients treated with other procedures (including incisional surgery, drainage device procedures, other glaucoma procedures) with patients receiving additional medications, at 1-year-post-treatment initiation.

Study Design:

The study is a prospective, observational cohort study and will not provide or recommend any treatment. Patients who have failed initial medical therapy with two glaucoma medications will be identified and enrolled at the time of scheduling of a laser surgery procedure or other procedure, or an additional course of therapy with medication as determined by their physician. Enrollment began in 2011 and will continue through 12 months of follow-up after enrollment targets have been reached.

Methods:

Two-sided 95% confidence intervals will be calculated for each estimate of treatment effect. Statistical methods will include generalized linear mixed models, propensity scores, stepwise multivariate logistic regression, mixed effect linear regression models, multivariate models, stratified analyses for race/ethnicity groups, and sensitivity analyses. The sample size is 2600 patients in 30 sites nationwide.

We will oversample for AHRQ priority populations including minorities (especially African Americans —at least a 25% enrollment, Hispanics, and Asians), and for those with Medicare and Medicaid insurance coverage.

Expected outputs:

Report 1: Baseline Findings Report will be submitted after patient enrollment is complete and will summarize the findings of the interim analyses of the baseline data.

Report 2: Final Study Report will be submitted after follow-up data collection is complete and will describe the study methods, summarize the study findings, discuss dissemination plans, and highlight key areas for future research.

Report 3: Primary Analysis Report will be submitted after final study analyses are complete and will summarize the findings of the primary analysis.

Report 4: Secondary Analyses Report will be submitted after final study analyses are complete and will summarize the findings of the secondary analyses.

Expected date of project completion:

Fall 2013

EHC Priority Condition:

Open-Angle Glaucoma

References:

1. Tielsch JM SA, Katz J, et al. . Racial variations in the prevalence of primary open-angle glaucoma. JAMA 1991;266:369-74.
2. Friedman DS WR, O'Colmain BJ, et al. . Prevalence of open-angle glaucoma among adults in the United States. Arch Ophthalmol 2004;122:532-8.
3. Congdon N OCB, Klaver CC, et al. . Causes and prevalence of visual impairment among adults in the United States. . Arch Ophthalmol 2004;122:477-85.
4. Sommer A TJ, Katz J, et al. . Racial differences in the cause-specific prevalence of blindness in east Baltimore. N Engl J Med 1991;325:1412-7.
5. Leske MC, Connell AM, Wu SY, et al. Incidence of open-angle glaucoma: the Barbados Eye Studies. The Barbados Eye Studies Group. Arch Ophthalmol 2001;119:89-95.
6. Varma R Y-LM, Francis BA, et al. . Prevalence of open-angle glaucoma and ocular hypertension in Latinos: the Los Angeles Latino Eye Study. 2004;11:1439-48.
7. Quigley HA WS, Rodriguez J, et al. . The prevalence of glaucoma in a population-based study of Hispanic subjects: Proyecto VER. Arch Ophthalmol 2001;119:1819-26.
8. Rotchford AP, Johnson GJ. Glaucoma in Zulus: a population-based cross-sectional survey in a rural district in South Africa. Arch Ophthalmol 2002;120:471-8.
9. Rotchford AP KJ, Muller MA, et al. . Temba glaucoma study: a population-based cross-sectional survey in urban South Africa. . Ophthalmology 2003;110.