title: Identification of persons with incident ocular diseases using health care claims databases.
abstract: OBJECTIVE
  To assess the extent to which incidence rates calculated for common ocular diseases by using claims data may be overestimated according to the length of the disease-free look-back period used in the analysis.
  
  
  METHODS
  Retrospective longitudinal cohort analysis.
  
  
  METHODS
  Billing records of 2457 persons continuously enrolled for 11 years in a managed-care network were searched for International Classification of Diseases (ICD-9-CM) diagnoses of cataract, open-angle glaucoma (OAG), nonexudative age-related macular degeneration (ARMD), and nonproliferative diabetic retinopathy (NPDR) at eye-care visits in the first half of 2001, the second half of 2010, and 2011. For each condition, incidence rates calculated by using "look-back" periods ranging from 0.5-9 years were compared with best estimates from a gold-standard period of 9.5 years.
  
  
  RESULTS
  With a 1-year disease-free look-back period, incidence was overestimated by 260% for cataract, 135% for OAG, 209% for ARMD, and 300% for NPDR. Expanding the disease-free look-back period to 3 years resulted in a reduction of incidence overestimation to 40% for cataract, 14% for OAG, 45% for ARMD, and 100% for NPDR. A 5-year look-back period yielded incidence rates that were overestimated by <30% for all 4 conditions.
  
  
  CONCLUSIONS
  In our claims-data analysis of 4 common ocular conditions, a disease-free interval ≤1 year insufficiently distinguished newly diagnosed from pre-existing disease, resulting in grossly overestimated incidence rates. Using look-back periods of 3-5 years, depending on the specific diagnosis, yielded considerably more accurate estimates of disease incidence.
authors: Department of Ophthalmology and Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan. Electronic address: jdstein@med.umich.edu.
authors: Joshua D
authors: JD
authors: Stein
authors: Taylor S
authors: TS
authors: Blachley
authors: David C
authors: DC
authors: Musch
mesh_terms: D002386:Cataract / Q000175:diagnosis / Q000453:epidemiology*; D016208:Databases, Factual; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007345:Insurance Claim Review / Q000706:statistics & numerical data*; D038801:International Classification of Diseases; D008137:Longitudinal Studies; D008268:Macular Degeneration / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008329:Managed Care Programs / Q000706:statistics & numerical data*; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies
references: JAMA Ophthalmol. 2013 Jan;131(1):119-20
references: 23307227
references: Ophthalmology. 2011 Jun;118(6):1031-7
references: 21310489
references: Ophthalmology. 2011 Jul;118(7):1318-26
references: 21481477
references: Health Serv Res. 2012 Apr;47(2):746-55
references: 21958217
references: J Cancer Epidemiol. 2012;2012:298369
references: 22792103
references: Surv Ophthalmol. 1997 Nov-Dec;42(3):271-8
references: 9406373
references: Arch Ophthalmol. 2003 Oct;121(10):1462-8
references: 14557184
references: Arch Ophthalmol. 2011 Aug;129(8):1053-60
references: 21825188
references: Arch Ophthalmol. 2009 Mar;127(3):320-7
references: 19273797
references: Invest Ophthalmol Vis Sci. 2007 Nov;48(11):5052-7
references: 17962457
references: Ophthalmology. 2012 Sep;119(9):1725-30
references: 22537615
references: Ophthalmology. 2003 Aug;110(8):1534-9
references: 12917168
references: Am J Ophthalmol. 2012 Sep;154(3):452-459.e2
references: 22789564