Adult Asthma Validation

Andrew Cave, Christina Davey, Rebecca Miyagishima, Irvin Mayers, Mohit Bhutani, Alan Kaplan, Tyler Williamson, Neil Drummond

Christina Davey (

Ethics approval granted



Asthma is a common chronic condition, affecting up to 10% of the adult population in Canada. However, estimates of prevalence and understandings of the characteristics of asthmatics are plagued by inaccuracies in definition and diagnosis. Billing diagnosis, for instance, is notoriously inaccurate for a variety of reasons, including avoidance of the diagnosis because of uncertainty on the part of the physician.

The purpose of the Adult Asthma Algorithm Validation Study is to develop and validate a case definition of adult asthma in patients who consult family physicians, in collaboration with the Canadian Primary Care Sentinel Surveillance Network (CPCSSN), to provide primary care estimates and characteristics of adult asthma as accurately as possible.


To develop a case definition which accurately identifies patients with asthma, following similar methodology to a previously developed and validated case definition for paediatric asthma.


The case definition will be developed based on a variety of data fields found in the SAPCReN-CPCSSN database, including ICD-9-CM diagnostic and procedures labels and codes, textual descriptors of asthma symptoms, and asthma related medications (e.g. inhaled cortico-steroids which are used to prevent and control asthma). The case definition will be validated by a gold standard case-by-case auditing of SAPCReN-CPCSSN patient records by two expert physicians and will be adjusted until it most closely approximates to the clinically defined cases. An algorithm based on the validated case definition will be used to retrieve patient records in the SAPCReN-CPCSSN database to identify characteristics of Canadian adults with asthma.