Risk Factors Predicting Loss to Follow-Up, Medication Noncompliance, and Poor Visual Outcomes Among Patients With Infectious Keratitis at a Public County Hospital

Purpose: Infectious keratitis is a vision-threatening condition requiring close follow-up and disciplined eye drop administration to achieve resolution. Although patients presenting to county hospitals often have more severe presentations, there is a paucity of risk and outcomes data in this setting. This study investigates risk factors predicting loss to follow-up (LTFU), medication noncompliance, and poor outcomes for infectious keratitis in the county hospital setting.

Methods: This was a retrospective case-control study at Zuckerberg San Francisco General Hospital and Trauma Center. Inclusion criteria were patients who had corneal cultures for suspected infectious bacterial or fungal keratitis between 2010 and 2021. Exclusion criteria were patients with viral keratitis only. Multivariable logistic regression was used to analyze the relationship of social and medical risk factors with LTFU, medication noncompliance, worsened visual acuity (VA), and delayed resolution time.

Results: Of 174 patients with infectious keratitis in this analysis, 69 (40.0%) had LTFU. Unemployment was associated with increased risk of LTFU (odds ratio 2.58, P = 0.049) and worse final VA ( P = 0.001). Noncompliance trended toward an association with homelessness (odds ratio 3.48, P = 0.095). Increasing age correlated with longer resolution time, with each 1-year increase associated with delayed resolution by 0.549 days ( P = 0.042).

Conclusions: Patients experiencing unemployment, homelessness, or increased age demonstrate higher risk for treatment barriers including loss to follow-up and medication noncompliance, resulting in worse VA and delayed time to resolution. These risk factors should be considered when determining the need for more deliberate follow-up measures in patients with infectious keratitis.