Predictors of Keratoplasty for KCN

Clinicians are often asked by their patients with keratoconus, “Will I need a corneal transplant?” Although we can reassure patients with keratoconus that many will not need a transplant, there are few current data to inform on who might need one. In keratoconus, the lifetime risk of needing a transplant in the United States has been estimated at 10% to 20%. Innovations in keratoconus management, including corneal cross-linking, intrastromal ring segments, and modern contact lenses, may have impacted corneal transplantation trends.

This large, retrospective cross-sectional study included 42,086 patients with keratoconus from January 2010 to December 2018, of whom 1282 (3.0%) had had a keratoplasty (≥1 PK and/or DALK). Administrative healthcare claims data from the IBM MarketScan Database were used, which came from over 150 employer-sponsored health insurance plans across 50 US states. The mean age was 41.3 ± 13.5 years. From 2010 to 2018, the number of keratoplasties per year decreased. In the fully adjusted analysis, female sex (OR, 0.87; 95% CI, 0.78–0.98) and living in a metropolitan area (OR, 0.75; 95% CI, 0.63–0.90) were associated with lower odds of keratoplasty. Patients aged 20 to 29 years (OR, 1.77; 95% CI, 1.31–2.41) and 30 to 39 years (OR, 1.61; 95% CI, 1.19–2.17) were more likely to have keratoplasty. Higher odds of receiving keratoplasty was associated with corneal hydrops (OR, 4.87; 95% CI, 4.07–5.82), Leber congenital amaurosis (OR, 2.41; 95% CI, 1.02–5.71), sleep apnea (OR, 1.46; 95% CI, 1.25–1.71), diabetes mellitus (OR, 1.32; 95% CI, 1.13–1.54), and depression (OR, 1.22; 95% CI, 1.03–1.44). Prior contact lens use (OR, 0.61; 95% CI, 0.50–0.74) and a history of glaucoma (OR, 0.60; 95% CI, 0.49–0.73) had lower odds. Atopic diseases and Down syndrome did not show a statistically significant association.

Prior studies have reported conflicting data in regard to some of the associations and other factors may have been influential. For instance, factors such as location, atopy, and Down’s syndrome may affect access to or the success of contact lens fitting. In Leber congenital amaurosis, patients rub their eyes, which may worsen keratoconus; however, the number of patients with Leber was low. The study also had limitations; it was based on insured patients and claims rather than clinical data and not all relevant information was collected (eg race, education level, income, and the chronicity of medical conditions).

Clinicians, though, may use these data to update their patients with keratoconus on recent trends. They can reply, “These days you may be less likely to need a transplant, particularly if you are female, young, and wear contact lenses unless you have had hydrops, Leber congenital amaurosis, sleep apnea, diabetes mellitus, and depression. Though research is needed to confirm these findings.” Nonetheless, these data highlight patient groups that may need closer surveillance and/or earlier crosslinking to prevent progression of the keratoconus.