Geographic atrophy and factors associated with disease progression among Medicare Advantage enrollees.

Background: Geographic atrophy (GA) is a form of advanced age-related macular degeneration (AMD) that can cause irreversible vision impairment and is responsible for approximately 20% of legal blindness in the United States. There is limited real-world evidence assessing health outcomes and health care resource use (HCRU) among individuals with GA.

Objective: To examine the progression from GA without subfoveal involvement (SFI) to GA with SFI, progression to irreversible blindness, and HCRU among older individuals with GA enrolled in Medicare Advantage Prescription Drug (MAPD) plans.

Methods: This retrospective study used claims data for MAPD-plan enrollees aged at least 65 years with an AMD diagnosis between 2018 and 2021. To assess progression of GA, development of blindness, and HCRU, propensity score matched cohorts of individuals with GA and without GA were identified and compared. For GA progression analysis, at least 12 months of follow-up was required, and patients were followed until the end of either follow-up or study period.

Results: Total 9,511 individuals with GA were matched 1:1 to individuals without GA. Among individuals with GA, initial diagnosis was primarily by an ophthalmologist (58.6%) followed by an optometrist (30.9%). The most common diagnostic imaging procedure at index was optical coherence tomography (53.0%). Mean follow-up time was 2.3 years. At index, 4,781 (50.3%) individuals had GA without SFI and 4,697 (49.4%) had GA with SFI. Among individuals with GA without SFI at index, 479 (10.2%) progressed to GA with SFI during the 12-month follow-up. Among individuals with GA without SFI at index, 173 (3.6%) developed irreversible blindness, compared to 312 (6.6%) of those with SFI, and 51 (0.5%) individuals without GA. Kaplan-Meier analysis indicated fastest progression to irreversible blindness among individuals with GA with SFI, followed by those without SFI (log-rank test P < 0.001). Both diagnosis of GA without SFI (hazard ratio [HR] [CI] = 6.77 [4.98-9.35], P < 0.001) and diagnosis of GA with SFI (HR [CI] = 12.59 [9.43-17.16], P < 0.001) were strongly associated with increased risk of developing irreversible blindness. Significant predictors of progression to GA with SFI were wet AMD at baseline (HR [CI] = 5.70 [4.63-6.99], P < 0.001), Elixhauser comorbidity score of 4-5 (HR [CI] = 1.46 [1.12-1.91], P = 0.006), and more than 5 (HR [CI] = 1.40 [1.02-1.89], P = 0.035).

Conclusions: GA with or without SFI was associated with progression to irreversible blindness in an MAPD-plan population. Patients with GA with SFI progressed to irreversible blindness faster than patients with GA without SFI. With the recent approval of GA treatments, future research is needed to assess the impacts on disease progression, including blindness.