Social Vulnerability Not Necessarily A Risk Factor For Glaucoma

Glaucoma prevalence is low among patients with higher social vulnerability scores, according to a study of California Medicare beneficiaries published in Ophthalmology Glaucoma. However, some types of the disease actually have a higher prevalence among the most vulnerable patients, researchers explain.

The researchers conducted a retrospective, cross-sectional study to examine associations of Centers of Disease Control and Prevention/Agency for Toxic Substances and Disease Registry Social Vulnerability Index (SVI) scores with prevalence of glaucoma and incidence of glaucoma surgery in 2019 California Medicare beneficiaries.

The study included 5,725,245 California Medicare beneficiaries 65 years of age or older with Part A and Part B coverage. SVI score was assessed overall and according to 4 themes — socioeconomic status (SVI-SES), household composition and disability (SVI-HCD), minority status and language (SVI-MSL), and housing type and transportation (SVI-HTT). The researchers looked at the incidence of glaucoma and glaucoma surgery among these groups. Participants were categorized into quartiles based on the 25th, 50th, 75th, and 100th percentile values for zip codes of beneficiaries in the 2019 California Medicare population (with higher SVI scores and quartiles indicated a higher level of social vulnerability).

The researchers discovered 215,814 (3.8%) patients had some type of glaucoma, and of those with glaucoma, 10,135 (4.7%) underwent glaucoma surgery. The study found that there were decreased odds of any glaucoma (95% CI=0.82, 0.84 for higher (Q4) vs lower (Q1), primary open-angle glaucoma (POAG, 95% CI=0.84, 0.87 for Q4 vs Q1), and secondary open-angle glaucoma (SOAG, 95% CI=0.55, 0.63 for Q4 vs Q1) in adjusted analyses for overall SVI score, where higher levels of SVI refer to higher levels of social vulnerability. However, there were increased odds of any glaucoma surgery (95% CI=1.12, 1.26 for Q4 vs Q1), minimally invasive glaucoma surgery (MIGS, 95% CI=1.15, 1.33 for Q4 vs Q1), and cyclophotocoagulation (CPC, 95% CI=1.29, 1.76 for Q4 vs Q1) for higher vs lower SVI quartile.

The study also found increased odds of angle closure glaucoma for the 4th vs 1st quartile of overall SVI score (aOR=1.06; 95% CI=1.01, 1.12 for Q4 vs. Q1; P <.001), but this finding was not statistically significant.

The researchers explain that the variable associations identified between glaucoma and social vulnerability necessitate continued research to reduce disparities in care.

“These varying findings suggest that associations between area-level measures of [social determinants of health] SDOH and glaucoma diagnosis and treatment are not straightforward in the California Medicare population, with a need to further evaluate specific SDOH and their associations with glaucoma care on the individual and structural levels,” the researchers explain.

“A potential explanation for this discrepancy is the difference in study populations. Most existing studies were performed in countries with nationalized healthcare systems, which increases the likelihood that all individuals within the country were captured in the same database, and also creates the possibility that there is increased access to care for glaucoma screening and diagnosis,” the report adds. “Conversely, it is possible that there are individuals within California who did not get captured in our study due to undiagnosed glaucoma, or were diagnosed with glaucoma outside of the Medicare system and did not get captured in analyses.”

Study limitations include the possibility of misclassification of the glaucoma diagnosis and surgery outcomes as well as study covariates, due to the assessment of Medicare variables; and the possibility that the results will not generalize to the entire US population.