title: Modification of claims-based measures improves identification of comorbidities in non-elderly women undergoing mastectomy for breast cancer: a retrospective cohort study.
abstract: Accurate identification of underlying health conditions is important to fully adjust for confounders in studies using insurer claims data. Our objective was to evaluate the ability of four modifications to a standard claims-based measure to estimate the prevalence of select comorbid conditions compared with national prevalence estimates.
  
  
  
  In a cohort of 11,973 privately insured women aged 18-64 years with mastectomy from 1/04-12/11 in the HealthCore Integrated Research Database, we identified diabetes, hypertension, deficiency anemia, smoking, and obesity from inpatient and outpatient claims for the year prior to surgery using four different algorithms. The standard comorbidity measure was compared to revised algorithms which included outpatient medications for diabetes, hypertension and smoking; an expanded timeframe encompassing the mastectomy admission; and an adjusted time interval and number of required outpatient claims. A χ2 test of proportions was used to compare prevalence estimates for 5 conditions in the mastectomy population to national health survey datasets (Behavioral Risk Factor Surveillance System and the National Health and Nutrition Examination Survey). Medical record review was conducted for a sample of women to validate the identification of smoking and obesity.
  
  
  
  Compared to the standard claims algorithm, use of the modified algorithms increased prevalence from 4.79 to 6.79 % for diabetes, 14.75 to 24.87 % for hypertension, 4.23 to 6.65 % for deficiency anemia, 1.78 to 12.87 % for smoking, and 1.14 to 6.31 % for obesity. The revised estimates were more similar, but not statistically equivalent, to nationally reported prevalence estimates. Medical record review revealed low sensitivity (17.86 %) to capture obesity in the claims, moderate negative predictive value (NPV, 71.78 %) and high specificity (99.15 %) and positive predictive value (PPV, 90.91 %); the claims algorithm for current smoking had relatively low sensitivity (62.50 %) and PPV (50.00 %), but high specificity (92.19 %) and NPV (95.16 %).
  
  
  
  Modifications to a standard comorbidity measure resulted in prevalence estimates that were closer to expected estimates for non-elderly women than the standard measure. Adjustment of the standard claims algorithm to identify underlying comorbid conditions should be considered depending on the specific conditions and the patient population studied.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave. Campus Box 8051, St. Louis, MO, 63110, USA.
authors.forename: Katelin B
authors.initials: KB
authors.lastname: Nickel
authors.affiliation: HealthCore, Inc., 123 Justison St Suite 200, Wilmington, DE, 19801, USA.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Wallace
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave. Campus Box 8051, St. Louis, MO, 63110, USA.
authors.forename: David K
authors.initials: DK
authors.lastname: Warren
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave. Campus Box 8051, St. Louis, MO, 63110, USA.
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Ball
authors.affiliation: HealthCore, Inc., 123 Justison St Suite 200, Wilmington, DE, 19801, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mines
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave. Campus Box 8051, St. Louis, MO, 63110, USA.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Fraser
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave. Campus Box 8051, St. Louis, MO, 63110, USA. molsen@wustl.edu.|Division of Public Health Sciences, Department of Surgery, Washington University School of Medicine, 660 South Euclid Ave. Campus Box 8100, St. Louis, MO, 63110, USA. molsen@wustl.edu.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Olsen
mesh_terms: D000293:Adolescent; D000328:Adult; D001943:Breast Neoplasms / Q000601:surgery*; D015897:Comorbidity / Q000639:trends*; D016208:Databases, Factual; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D005544:Forecasting; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D007345:Insurance Claim Review; D008408:Mastectomy; D008485:Medical Audit; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies; D055815:Young Adult
keywords: Administrative health claims data; Breast cancer; Comorbidity; Diabetes; Hypertension; Mastectomy; Obesity