Socioeconomic Correlates of Keratoconus Severity and Progression

Abstract

Purpose: The purpose of this study was to investigate the social determinants of health for keratoconus.

Methods: In this retrospective cohort study of patients with keratoconus, the electronic health record was reviewed for keratometry, treatments received, clinical comorbidities, and social characteristics. Outcomes included severe keratoconus at presentation (steep keratometry ≥52 diopters), disease progression (≥0.75 diopters increase from the first to the most recent clinical visit), and corneal transplantation. Logistic regression was used to evaluate factors associated with severity at presentation and corneal transplantation. Cox proportional hazards modeling was used to evaluate progression.

Results: A total of 1038 patients with keratoconus were identified, 725 (70%) of whom had baseline imaging. Compared with commercially insured patients, Medicaid recipients were more likely to have severe keratoconus, independent of social and clinical confounders [odds ratio (OR) 1.94, 95% confidence interval (CI), 1.12-3.35, P = 0.017]. Male sex was independently associated with progression (hazard ratio = 1.38, 95% CI, 1.03-1.84, P = 0.030). Medicare and Medicaid recipients were more likely to require transplantation compared with commercially insured patients (OR 2.71, 95% CI, 1.65-4.46, P < 0.001 and OR 1.74, 95% CI, 1.08-2.80, P = 0.022, respectively). Other social determinants of health, including non-White race/ethnicity, limited English proficiency, and unemployment, were associated with the outcomes only in univariate analysis. Obstructive sleep apnea, atopy, body mass index, and tobacco use were not associated with any outcome.

Conclusions: Socioeconomic factors were more consistent predictors of keratoconus severity and corneal transplantation compared with clinical factors that have received relatively greater attention in the keratoconus literature.

FIGURE 1.

Derivation of the study sample. A total of 1,038 were initially identified using ICD codes, 877 of whom had clinical documentation consistent with keratoconus. The study sample was further narrowed for each outcome based on the number of patients with baseline imaging (725), final treatment information (716), and both baseline and follow-up imaging (475).