January 2013
Volume 54, Issue 1
Free
Letters to the Editor  |   January 2013
Author Response: Prevalence of Corneal Dystrophies in the United States: Estimates from Claims Data
Author Affiliations & Notes
  • David C. Musch
    From the Department of Ophthalmology and Visual Sciences, Medical School; the
    Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan; and the
  • Leslie M. Niziol
    From the Department of Ophthalmology and Visual Sciences, Medical School; the
  • Joshua D. Stein
    From the Department of Ophthalmology and Visual Sciences, Medical School; the
  • Roheena M. Kamyar
    UPMC Eye Center, Eye & Ear Institute, University of Pittsburg, Pittsburg, Pennsylvania.
  • Alan Sugar
    From the Department of Ophthalmology and Visual Sciences, Medical School; the
Investigative Ophthalmology & Visual Science January 2013, Vol.54, 388. doi:10.1167/iovs.12-11519
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      David C. Musch, Leslie M. Niziol, Joshua D. Stein, Roheena M. Kamyar, Alan Sugar; Author Response: Prevalence of Corneal Dystrophies in the United States: Estimates from Claims Data. Invest. Ophthalmol. Vis. Sci. 2013;54(1):388. doi: 10.1167/iovs.12-11519.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Møller and colleagues 1 raise a cogent observation in noting that relying on claims data to reveal information on prevalence of corneal dystrophies has important limitations, especially regarding diagnostic accuracy. While we may not have discussed this limitation as fully as the letter's authors would have desired, we do identify the source of these diagnostic codes—“an eye care provider (ophthalmologist or optometrist)”—and we point out in our “Discussion” that coding, “particularly with endothelial dystrophy,” is subject to inaccuracies in claims data. 2 It goes without saying that a diagnostic code for a specific corneal dystrophy in claims data does not provide assurance that the diagnosis was verified by electron microscopy, histology, family history, or genetic tests. 
We contend that including information on dystrophies that were assigned an ICD-9-CM code of “endothelial dystrophy” should be included. Truly, they represent what the authors term “an etiologically heterogenous group of diseases of a degenerative nature” and we share the authors' anticipation of better delineation of corneal dystrophies that will come from applying the new IC3D coding. However, equally truly, a genetic basis for endothelial dystrophies has been vetted by Baratz et al., 3 and endothelial dystrophies represent a major cause of corneal transplantation in the United States. Such surgery is typically performed by highly trained corneal specialists whose diagnostic coding is based on a thorough evaluation of the cornea and is likely to be accurate. 
Indeed, the information we provided does estimate prevalence rather than frequency, as it fits the epidemiologic definition of prevalence (the number of cases in a given population at a designated time). Studies that rely on claims data surely are subject to limitations, and associations uncovered in such studies should be viewed as hypothesis-generating rather than causal in nature. They also provide important insights into the health care burden imposed by corneal dystrophies, as claims data reflect actual care provision for the specified condition, which can lead to better estimates of cost. 
We look forward to future reports that estimate the prevalence of corneal dystrophies in defined populations and rely on more accurate coding of corneal dystrophies, which—as Møller et al. note—is needed. 
References
Møller HU Sunde L. Prevalence of corneal dystrophies in the United States: estimates from claims data. Invest Ophthalmol Vis Sci . 2013; 54: 387. [CrossRef] [PubMed]
Musch DC Niziol LM Stein JD Prevalence of corneal dystrophies in the United States: estimates from claims data. Invest Ophthalmol Vis Sci . 2011; 52: 6959–6063. [CrossRef] [PubMed]
Baratz KH Tosakulwong N Ryu E E2-2 protein and Fuchs' corneal dystrophy. N Engl J Med . 2010; 363: 1016–1024. [CrossRef] [PubMed]
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×