Digestive Diseases and Sciences

, Volume 55, Issue 9, pp 2592–2598

Validation of ICD-9-CM Diagnostic Codes for Inflammatory Bowel Disease Among Veterans

  • Selvi Thirumurthi
  • Reezwana Chowdhury
  • Peter Richardson
  • Neena S. Abraham
Original Article

DOI: 10.1007/s10620-009-1074-z

Cite this article as:
Thirumurthi, S., Chowdhury, R., Richardson, P. et al. Dig Dis Sci (2010) 55: 2592. doi:10.1007/s10620-009-1074-z

Abstract

Background

Inflammatory bowel disease (IBD) is well described among young whites and less so among the elderly and non-whites. Population-level data is required to assess outcomes among minority groups.

Aim

To validate diagnostic codes for IBD from the Department of Veterans Affairs.

Methods

National databases were used to identify local patients with Crohn’s disease (CD) and ulcerative colitis (UC), the extra-intestinal manifestations and surgical procedures associated with IBD. Diagnosis was confirmed by manual chart abstraction. Multivariable logistic regression was used to derive diagnostic algorithms for CD and UC, which were then validated in an independent cohort.

Results

The test cohort of 3,827 patients (1,316 potential cases, 2,511 random controls) was predominantly male (94%), white (56%), and of age of 58 (standard deviation 15). The positive predictive value (PPV) of CD codes was superior (88–100%) to UC (50–93%). The accuracy of extra-intestinal manifestations and surgeries was poor (PPV 0–29%). ICD-9-CM code 555.x without 560.9 had a PPV of 91% for CD in the validation cohort. Code 556.x with age, gender, and race factors was highly predictive of UC (c-statistic 0.9, PPV of 81%).

Conclusion

VA administrative data can diagnose elderly and non-white patients with IBD.

Keywords

ICD-9-CM codeUlcerative colitisCrohn’s diseaseValidation studiesVeteransElderlyPositive predictive value

Abbreviations

VA

Department of Veterans Affairs

PTF

Patient treatment file

OPC

Outpatient care file

VA-PBM

Veterans Affairs Pharmacy Benefits Management

BIRLS

Beneficiary identification and records locator subsystem death file

MEDVAMC

Michael E. DeBakey VA Medical Center

IBD

Inflammatory bowel disease

UC

Ulcerative colitis

CD

Crohn’s disease

CPT

Current procedural terminology

ICD-9-CM

International classification of diseases, ninth revision, clinical modification

SD

Standard deviation

PPV

Positive predictive value

CI

Confidence interval

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Selvi Thirumurthi
    • 1
    • 4
  • Reezwana Chowdhury
    • 4
  • Peter Richardson
    • 1
    • 2
  • Neena S. Abraham
    • 1
    • 2
    • 3
    • 4
  1. 1.Section of Health Services ResearchHouston Center for Quality of Care & Utilization StudiesHoustonUSA
  2. 2.The Gastrointestinal Outcomes in Geriatrics (GO-GERI) UnitMichael E. DeBakey Veterans Affairs Medical CenterHoustonUSA
  3. 3.Section of Digestive DiseasesMichael E. DeBakey Veterans Affairs Medical CenterHoustonUSA
  4. 4.Department of Medicine, Gastroenterology and Hepatology DivisionBaylor College of MedicineHoustonUSA