Variations in treatment among adult-onset open-angle glaucoma patients

Objective: To determine the predictors of treatment for glaucoma and suspect glaucoma in a nationally representative sample of diagnosed persons. Design: Retrospective cohort study of persons enrolled in a large managed care organization. Participants: Thirty-five thousand seven hundred fifty-four diagnosed suspects, 5265 diagnosed glaucoma persons, and 2633 individuals coded as having cupping of the optic disc. Methods: Linked pharmacy and patient care information were used to examine the predictors of initiating glaucoma treatment in this cohort of persons insured by a single managed care organization. Predictors entered into logistic regression models included diagnostic group (suspect vs. diagnosed), age group, gender, region of the country, provider type at the initial visit (optometrist or ophthalmologist), diagnosis index date divided into 2 periods (1995-1998 and 1999-2001), and health plan enrollment duration after the initial diagnosis. Main Outcome Measures: Occurrence of and factors associated with treatment for glaucoma (argon laser trabeculoplasty [ALT], surgery, or topical ocular hypotensives). Results: A logistic regression model adjusting for glaucoma status, age, region, clinician seen at initial visit, and index date found that women were less likely to undergo treatment (topical ocular hypotensives, ALT, or surgery) than men (odds ratio, 0.76; 95% confidence interval, 0.71-0.80). Factors other than gender that were associated with greater likelihood of treatment were glaucoma diagnosis, older age, region, and longer follow-up. Conclusions: We have documented wide variation in treatment among individuals diagnosed as having glaucoma or as glaucoma suspects. Women were 24% less likely to be treated than men, and younger individuals were far less likely to be treated than older ones. Furthermore, treatment varied by region of the country. Understanding the sources of these variations will help in determining how to arrive at better management strategies for individuals with glaucoma and suspect glaucoma.