title: Trends in Corneal Transplantation in Keratoconus.
abstract: To determine recent trends in and sociodemographic/comorbid conditions associated with penetrating keratoplasty (PK) and lamellar keratoplasty (LK) for keratoconus (KCN).
  
  
  
  Patients with KCN and subsequent PK and LK procedures were identified using International Classification of Diseases, 9th revision (ICD-9) and Current Procedural Terminology (CPT) billing codes. The change in surgical rates was calculated over a decade, and multivariate analysis demonstrated factors associated with undergoing surgery.
  
  
  
  A total of 21,588 patients with KCN underwent 1306 PK procedures and 109 LK procedures during the study period. Individuals were significantly less likely to undergo PK from 2009 to 2012 compared with 2001 to 2008 [odds ratio (OR) 0.57, 95% confidence interval (CI) 0.47-0.68, P < 0.001]. Multivariate analysis revealed the factors that increased the likelihood of PK alone and included age 20 to 40 (OR 1.90, 95% CI, 1.19-3.04, P < 0.001), black race (OR 1.36, 95% CI, 1.06-1.74, P = 0.01), and education less than a bachelor's degree or only a high school diploma (OR 1.94-2.84, P < 0.001 for all comparisons). Female sex (OR 0.74, 95% CI, 0.63-0.88, P < 0.001) and household net worth either between 150 and 249k (OR 0.64, 95% CI, 0.48-0.84, P < 0.001) or more than $500,000 (OR 0.71, 95% CI, 0.51-0.99, P = 0.03) were traits associated with decreased odds of PK. No significant associations for LK were observed.
  
  
  
  The rate of PK in KCN is decreasing in the United States. The third or fourth decade of life, male sex, black race, lower education, and greater household net worth are associated with increased odds of PK.
authors.affiliation: *Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA; †Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA; ‡Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA; and §Leonard Davis Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sarezky
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Orlin
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.forename: Brian L
authors.initials: BL
authors.lastname: VanderBeek
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D016039:Corneal Transplantation / Q000639:trends*; D005006:Ethnicity; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007640:Keratoconus / Q000453:epidemiology / Q000601:surgery*; D015948:Keratoplasty, Penetrating / Q000639:trends*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology