The effect of social determinants of health on severity of microbial keratitis presentation at a tertiary eye care hospital in Southern India

Abstract

Purpose: Understanding the association between social determinants of health (SDoHs) and microbial keratitis (MK) can inform underlying risk for patients and identify risk factors associated with worse disease, such as presenting visual acuity (VA) and time to initial presentation.

Methods: This was a cross-sectional study was conducted with patients presenting with MK to the cornea clinic at a tertiary care hospital in Madurai, India. Patient demographics, SDoH survey responses, geographic pollution, and clinical features at presentation were collected. Descriptive statistics, univariate analysis, multi-variable linear regression models, and Poisson regression models were utilized.

Results: There were 51 patients evaluated. The mean age was 51.2 years (SD = 13.3); 33.3% were female and 55% did not visit a vision center (VC) prior to presenting to the clinic. The median presenting logarithm of the minimum angle of resolution (logMAR) VA was 1.1 [Snellen 20/240, inter-quartile range (IQR) = 20/80 to 20/4000]. The median time to presentation was 7 days (IQR = 4.5 to 10). The average particulate matter 2.5 (PM2.5) concentration, a measure of air pollution, for the districts from which the patients traveled was 24.3 μg/m3 (SD = 1.6). Age- and sex-adjusted linear regression and Poisson regression results showed that higher levels of PM2.5 were associated with 0.28 worse presenting logMAR VA (Snellen 2.8 lines, P = 0.002). Patients who did not visit a VC had a 100% longer time to presentation compared to those who did (incidence rate ratio = 2.0, 95% confidence interval = 1.3-3.0, P = 0.001).

Conclusion: Patient SDoH and environmental exposures can impact MK presentation. Understanding SDoH is important for public health and policy implications to mitigate eye health disparities in India.

Keywords: Air pollution; South India; corneal ulcers; international eye care; microbial keratitis; social determinants of health.

Figure 1

Point map displaying locations of patient residences (approximated by village) and their relationship with presenting Snellen VA and PM2.5 concentration. VA was stratified into normal vision (better than or equal to 20/40), low vision (between 20/40 and 20/400), and blindness (worse than 20/400) for ease of display, guided by definitions provided by the World Health Organization[25]

Figure 2

Point map displaying locations of patient residences (approximated by village) and their relationship with time to initial presentation (days) and PM2.5 concentration. Time to presentation was categorized ≤7 days, 8 to 14 days, and >14 days for ease of display