Infectious Keratitis After Keratoplasty in the United States: Analysis of a National Medicare Claims Data Set

Purpose: The aim of this study was to assess the incidence, trends, and risk factors of infectious keratitis (IK) and subsequent repeat keratoplasty after penetrating keratoplasty (PK) and endothelial keratoplasty (EK). Methods: Using a retrospective cohort study design, IK cases within 6 months of keratoplasty were identified using billing codes among 100% Medicare beneficiaries aged 65 years and older who underwent either PK or EK between 2011 and 2020. Multivariable logistic regression models were used to evaluate factors associated with postkeratoplasty IK. Results: We identified 115, 588 keratoplasties, of which 20.0% (n = 23, 144) were PK and 80.0% (n = 92, 444) were EK. IK developed within 6 months with a rate of 3.32% (n = 769) post-PK and 0.72% (n = 666) post-EK. Overall rates of IK decreased from 16.05 to 9.61 per 1000 keratoplasties between 2011 and 2020 (P, 0.001). The median interval between keratoplasty and diagnosis of IK was 73 days (interquartile range: 29-114 days) for PK and 74 days (interquartile range: 38-116 days) for EK. After IK, 22.9% (n = 176) and 23.8% (n = 159) eyes underwent repeat keratoplasty within 1 year for PK and EK, respectively. The occurrence of IK after PK was associated with age 85 years and older [odds ratio (OR): 1.38; 95% confidence interval (CI): 1.13-1.68] relative to patients aged 65 to 74 years. The occurrence of IK after EK was also associated with age 85 years and older (OR: 1.44; 95% CI: 1.14-1.82) relative to patients aged 65 to 74 years. Conclusions: IK was 4 times more common after PK than EK and the complication was associated with older age. Our findings may help corneal surgeons in counseling patients at higher risk and guiding their postoperative care.