Geographic Variation in the Use of Diagnostic Testing of Patients with Newly Diagnosed Open-Angle Glaucoma

Abstract

Purpose: To determine the extent of geographic variation in the proportion of patients with newly diagnosed open-angle glaucoma (OAG) undergoing visual field (VF) testing, fundus photography (FP), and other ocular imaging (OOI) among patients residing in different US communities.

Design: Retrospective, longitudinal cohort study.

Participants: All enrollees with newly diagnosed OAG enrolled in a managed care network between 2001 and 2014.

Methods: We identified all persons in the plan with incident OAG residing in 201 communities across the United States. All communities contributed ≥20 enrollees. The proportion of enrollees undergoing ≥1 VF test, FP, OOI, and no testing of any type in the 2 years after first OAG diagnosis was determined for each community, and comparisons were made to assess the extent of variation in use of diagnostic testing among patients residing in the different communities.

Main outcome measures: Receipt of VF testing, FP, OOI, or none of these tests in the 2 years after initial OAG diagnosis.

Results: Of the 56675 enrollees with newly diagnosed OAG, the mean proportion of patients undergoing VF testing within 2 years of initial diagnosis was 74%±7%, ranging from as low as 51% in Rochester, Minnesota, to as high as 95% in Lancaster, Pennsylvania. The mean proportion undergoing OOI was 63%±10% and varied from 34% in Palm Springs/Rancho Mira, California, to 85% in Charleston, South Carolina. The mean proportion receiving FP was 26%±10% and ranged from as low as 3% in Fresno, California, to as high as 57% in Harlingen, Texas. The proportion undergoing no glaucoma testing ranged from 0% in Binghamton, New York, to as high as 35% in 2 other communities.

Conclusions: In many US communities, a high proportion of patients are undergoing testing according to established practice guidelines. However, in several communities, less than 60% of patients with newly diagnosed OAG are undergoing VF testing in the 2 years after initial OAG diagnosis, and in a few communities >1 in 4 patients have no record of glaucoma diagnostic testing of any type. Additional research is needed to understand factors driving this variation in practice patterns and its impact on patient outcomes.

Figure 1:. Utilization of Visual Field Testing in the Two Years Following Incident Glaucoma Diagnosis Among Communities Throughout the United States

Map of the United States divided into 306 hospital referral regions. Communities with larger proportions of patients receiving visual field testing in the 2 years after initial open-angle glaucoma diagnosis are shaded dark colors relative to other communities with lower proportions of patients undergoing perimetry. Communities shaded white had fewer than 20 enrollees with newly-diagnosed open-angle glaucoma. HRR = hospital referral region

Figure 2:. Turnip Graph Showing the Proportion of Patients with Incident Open-Angle Glaucoma Who Underwent Visual Field Testing, Fundus Photography, Other Ocular Imaging, and None of These Tests in the Two Years After Initial Diagnosis for Communities Throughout the United States.

Each dot on the plot represents a specific hospital referral region. Plots that are short and wide depict little variation in utilization and few outlier communities. Plots that are long and narrow reflect lots of variation in utilization with many outlier communities. VF = Visual Field; FP = Fundus photography; OOI = Other ocular imaging

Figure 3:. Utilization of Fundus Photography in the Two Years Following Incident Glaucoma Diagnosis Among Communities Throughout the United States

Map of the United States divided into 306 hospital referral regions. Communities with larger proportions of patients receiving fundus photography in the 2 years after initial open-angle glaucoma diagnosis are shaded dark colors relative to other communities with lower proportions of patients undergoing fundus photography. Communities shaded white had fewer than 20 enrollees with newly-diagnosed open-angle glaucoma. HRR = hospital referral region

Figure 4:. Utilization of Other Ocular Imaging Testing in the Two Years Following Incident Glaucoma Diagnosis Among Communities Throughout the United States

Map of the United States divided into 306 hospital referral regions. Communities with larger proportions of patients receiving other ocular imaging in the 2 years after initial open-angle glaucoma diagnosis are shaded dark colors relative to other communities with lower proportions of patients undergoing other ocular imaging. Communities shaded white had fewer than 20 enrollees with newly-diagnosed open-angle glaucoma. HRR = hospital referral region