Purpose: The aim of this study was to evaluate the association between diabetes mellitus (DM) and keratoconus.
Methods: We conducted 2 substudies: (1) Retrospective comparison of the prevalence of DM in patients with keratoconus with that of control patients without keratoconus and (2) Cross-sectional study of the severity of keratoconus in diabetic keratoconus-affected patients and nondiabetic keratoconus-affected patients. Patients seen at the Wills Eye Hospital Cornea Service from January 2008 to August 2012 were included. Study 1 included 1377 patients with keratoconus and 4131 controls without keratoconus. Study 2 involved 75 type 2 diabetic keratoconus-affected patients and 225 nondiabetic keratoconus-affected patient, excluding patients with bilateral keratoplasty. In patients with a history of a corneal transplant in 1 eye, the other eye was included. Keratoconus severity was based on the topographic mean keratometry in the more severely affected eye.
Results: Two of 1377 (0.15%) keratoconus-affected patients had type 1 DM, which was similar to that of 20 of the 4131 (0.49%) matched controls (P = 0.139). The prevalence of type 2 DM was higher in patients with keratoconus (93/1377, 6.75%) than in matched controls (200/4131, 4.84%) (P = 0.005). When categorized by age group, the prevalence of type 2 DM was higher in patients with keratoconus than in those without keratoconus in patients aged between 25 and 44 years (P = 0.036) and 45 and 64 years (P = 0.047). Using multinomial logistic regression analyses, the probability/risk of being in the severe keratoconus-affected group as opposed to the mild keratoconus-affected group was higher in patients with DM than in those without DM (P = 0.006; odds ratio = 2.691; 95% confidence interval, 1.330–5.445).
Conclusions: There may be a positive association between type 2 DM and the presence and severity of keratoconus.
Cornea Service, Wills Eye Hospital, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA.
Reprints: Christopher J. Rapuano, MD, Wills Eye Hospital, 840 Walnut Street, Suite 920, Philadelphia, PA 19107 (e-mail: email@example.com).
C. J. Rapuano is a consultant for Allergan, Bausch and Lomb, and Merck, and he is on the Speakers Bureau for Allergan, Alcon, Bausch and Lomb, and Merck. The remaining authors have no funding or conflicts of interest to disclose.
Received March 01, 2014
Accepted April 24, 2014