Ascertaining asthma status in epidemiologic studies: a comparison between administrative health data and self-report

Table 2 Asthma prevalence according to data source for defining asthma

Source for asthma definition	Subjects with asthma n	Subjects with valid answers n	Prevalence^a %	Corrected prevalence^b %
Administrative databases (asthma-related health services)^c
≥ 2 PC within 1 year or ≥ 1 H	801	1643	48.8	12.8
≥ 2 PC within 2 years or ≥ 1 H	836	1643	50.9	13.7
≥ 2 PC within 3 years or ≥ 1 H	853	1643	51.9	13.9
≥ 2 PC within 5 years or ≥ 1 H	875	1643	53.3	14.5
≥ 2 PC within 30 years or ≥ 1 H	897	1643	54.6	15.0
Self-report
Ever had asthma	807	1640	49.2	19.3
Ever had asthma diagnosed by a physician	762	1638	46.5	16.3

H, hospitalization; PC, physician claims
^a By design, the targeted prevalence of asthma among study participants was 50%
^b Corrected by applying weights corresponding to the inverse of the sampling probability from the Quebec Birth Cohort on Immunity and Health into the Survey on Childhood Environment and the Development of Allergic Diseases (stratified sampling among four strata, according to BCG vaccination status and asthma)
^c Lookback window from 1983 to 2012 (30 years)
Compilation based on data from the ©Government of Quebec, Institut de la statistique du Québec, Survey on Childhood Environment and the Development of Allergic Diseases, 2012 and Quebec Birth Cohort on Immunity and Health, 2017. Institut de la statistique du Québec is not responsible for compilations or interpretation of results

ISSN: 1471-2288