Reconcilable differences: a cross-sectional study of the relationship between socioeconomic status and the magnitude of short-acting beta-agonist use in asthma.
OBJECTIVE
To assess the association between socioeconomic status (SES) and short-acting (SA) beta-agonist use, controlling for asthma severity.


METHODS
Cross-sectional study.


METHODS
Vancouver, BC, Canada.


METHODS
Two hundred two asthmatics between 19 years and 50 years of age and residing in the greater Vancouver regional district.


METHODS
The quantity of SA beta-agonist used in the previous year was collected by self-report; pulmonary function and beta-receptor genotype were measured on each participant. SES was measured at both the individual and population levels. Five methods of adjustment for asthma severity were used, as follows: the Canadian Asthma Consensus Guidelines, three previously developed asthma-severity scores, and forward stepwise multiple regression modeling. Polychotomous logistic regression was used to assess all relationships.


RESULTS
Independent of the method used to measure SES or adjust for asthma severity, lower SES was consistently and significantly associated with the use of greater amounts of SA beta-agonist. Adjusting for severity using the multivariate model explained the most variance of SA beta-agonist use (R(2) adjusted, 0.35 to 0.37). In this model, social assistance recipients were more likely to use greater amounts of SA beta-agonist (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.7 to 6.5). An inverse relationship between SA beta-agonist use and both annual household income (> $50,000; OR, 0.28; 95% CI, 0.13 to 0.60; and $20,000 to $50,000; OR, 0.44; 95% CI, 0.21 to 0.96; relative to <$20,000) and education (completing a bachelor's degree vs no formal education; OR, 0.25; 95% CI, 0.14 to 0.71). Participants living in a neighborhood with higher median household income (OR, 0.91; 95% CI, 0.84 to 0.98 per $1,000 increase) or a higher prevalence of having attained a bachelor's degree (OR, 0.96; 95% CI, 0.84 to 0.98 per 1% increase) were also less likely use greater amounts of SA beta-agonist. Results were consistent for neighborhood unemployment rate.


CONCLUSIONS
The social gradient in asthma-related outcomes may be at least partially attributable to poorer asthma control in lower-SES asthmatics.
Lynd
Larry D
LD
Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.
Sandford
Andrew J
AJ
Kelly
Erin M
EM
Paré
Peter D
PD
Bai
Tony R
TR
Fitzgerald
J Mark
JM
Anis
Aslam H
AH
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000328:Adult; D001249:Asthma / Q000188:drug therapy* / Q000517:prevention & control; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D012923:Social Class
D000318:Adrenergic beta-Agonists