Original Article

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 ThirumurthiAffiliated withSection of Health Services Research, Houston Center for Quality of Care & Utilization StudiesDepartment of Medicine, Gastroenterology and Hepatology Division, Baylor College of Medicine Email author 
  • , Reezwana ChowdhuryAffiliated withDepartment of Medicine, Gastroenterology and Hepatology Division, Baylor College of Medicine
  • , Peter RichardsonAffiliated withSection of Health Services Research, Houston Center for Quality of Care & Utilization StudiesThe Gastrointestinal Outcomes in Geriatrics (GO-GERI) Unit, Michael E. DeBakey Veterans Affairs Medical Center
  • , Neena S. AbrahamAffiliated withSection of Health Services Research, Houston Center for Quality of Care & Utilization StudiesThe Gastrointestinal Outcomes in Geriatrics (GO-GERI) Unit, Michael E. DeBakey Veterans Affairs Medical CenterSection of Digestive Diseases, Michael E. DeBakey Veterans Affairs Medical CenterDepartment of Medicine, Gastroenterology and Hepatology Division, Baylor College of Medicine

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

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 code Ulcerative colitis Crohn’s disease Validation studies Veterans Elderly Positive predictive value