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

demographic data such as age, gender and postal code for place of residence. The third
domain is disease, which includes most responsible diagnosis, co-morbidities and
complications. The fourth domain is the medical and surgical procedures.
Although administrative data offers practical advantages, investigators have no control
over the quality of the data collection; therefore, accuracy and completeness of these
datasets has always been a source of concern [22-25]. The best solution to overcome the
concern of validity is to link several independently collected databases [26].
Although administrative data may be accompanied by a trade-off in credibility, this is
often counterbalanced by the feasibility and comprehensiveness.
In Canada, administrative databases were implemented by provincial governments after
the introduction of universal medical insurance. The structure of the administrative
databases used in this study is described below:
2.2.1 Hospital Discharge Abstract Database (Inpatient database)
The Discharge Abstract Database is one of the key database holdings in the Calgary
Health Region. It is completed according to instructions outlined in the Canadian
Institute of Health Information (CIHI) Abstract Manual [27] after patients leave the
hospital (acute care, chronic care, and rehabilitation) to reflect diagnoses and procedures
performed during the period of hospitalization [28]. The database records up to sixteen
diagnostic (ICD-9-CM) and ten procedure codes (ICD-9-CM and Canadian Classification
of Diagnostic, Therapeutic, and Surgical Procedures), demographic data (e.g. age and
gender), health care number, and admission and discharge dates in the system. The most
responsible diagnosis in CIHI is defined as —the one diagnosis which describes the most
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