Development of an ICD Coding Definition for Inflammatory Bowel ...

2-Manitoba: ( Population≈1,140,000)
Bernstein et al. [2] used Manitoba health insurance databases to identify IBD patients.
Physicians billing claims and hospital abstracts were searched for International
Classification of Diseases, 9 th revision (ICD-9) diagnostic codes for CD and UC between
1984 and 1998.
Those with ≥3 health care contacts from 1984-1993 and at least one contact from 1993-
1995 were included in the study. A questionnaire was sent to the patients (60% response
rate) and chart reviews were done on 16% of the respondents to establish and validate a
definition for the identify IBD patients. Considering equal sensitivity and specificity of
90%, the following criteria were developed:
• For individuals who had been a resident or registered with the insurance system
for at least 2 years, cases were those with at least 5 health care contacts (physician
claim or hospitalization) with diagnostic codes of IBD.
• For residents who had been insured for less than 2 years, 3 health care contacts
were required for the diagnosis of IBD.
• Those who fulfilled both CD and UC criteria were classified as CD or UC based
on the majority diagnosis of the 9 most recent coantacts.
The annual mid-year population for incidence and prevalence rates was obtained from
Manitoba Health registry. The date of the first medical contact was considered as the date
of diagnosis and the incidence rates were calculated for the cases with the first medical
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