Accuracy of Administrative Coding for Type 2 Diabetes in Children, Adolescents, and Young Adults

  1. Erinn T. Rhodes, MD, MPH12,
  2. Lori M.B. Laffel, MD, MPH123,
  3. Tessa V. Gonzalez, AB1 and
  4. David S. Ludwig, MD, PHD12
  1. 1Division of Endocrinology, Children’s Hospital Boston, Boston, Massachusetts
  2. 2Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
  3. 3Pediatric, Adolescent, and Young Adult Section, Joslin Diabetes Center, Boston, Massachusetts
  1. Address correspondence and reprint requests to Erinn T. Rhodes, MD, MPH, Division of Endocrinology, Children’s Hospital Boston, 300 Longwood Ave., Boston, MA 02115. E-mail: erinn.rhodes{at}childrens.harvard.edu

Administrative data are used with increasing frequency in research. However, validity of such data, including International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) codes (1), varies across diseases and settings (2–12). The ICD-9-CM coding for diabetes in youth may be especially susceptible to errors. While most diagnoses of diabetes in American youth are type 1 diabetes (13), incidence of type 2 diabetes is increasing (14). Rising prevalence of pediatric obesity (15) makes distinguishing between type 1 and type 2 diabetes at diagnosis difficult, and type 2 diabetes ICD-9-CM codes (250.X0/X2) include “unspecified” diabetes (1). Our aim was to evaluate the positive predictive value (PPV) of type 2 diabetes ICD-9-CM codes in children, adolescents, and young adults.

RESEARCH DESIGN AND METHODS—

In a retrospective chart review, we evaluated 432 patients aged <26 years as of 31 January 2005 with at least one visit to the Endocrine/Diabetes or Obesity Programs at Children’s Hospital Boston in Boston, Massachusetts, from 1 July 2003 to 31 January 2005 and at least one type 2 diabetes ICD-9-CM code (250.X0/X2, X = 0–9) from inpatient/outpatient sites before 5 April 2005. We identified 455 patients utilizing scheduling and billing information, and excluded 23 patients without completed visits.

To contrast the accuracy of type 2 diabetes ICD-9-CM codes with type 1 diabetes ICD-9-CM codes, we reviewed charts of patients <26 years as of 31 January 2005 with at least one visit to the Endocrine/Diabetes Program from 1 July 2003 to 31 January …

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