Sex differences in outcomes after discharge from Alberta emergency departments for asthma: A large population-based study

ABSTRACT

Objective: Asthma exacerbations frequently result in emergency department (ED) visits. While sex differences have been identified in some asthma studies, there is a paucity of literature on sex differences in the ED setting, especially population-based ones. This study examines sex differences in important outcomes of patients discharged from EDs for acute asthma in Alberta, Canada. Methods: Alberta residents aged from 2 to 55 years discharged from EDs with a primary diagnosis of asthma during 1999–2011 were identified from administrative databases from a single-payer health care system for the entire geographic region of Alberta. Multivariable Cox regression models analyzed time to first follow-up physician or specialist visit, and logistic regression models analyzed the binary outcome of ED return within 30 days for asthma. Results: There were 115,853 discharged patients analyzed (40.4% and 59.1% female in pediatric and adult groups, respectively). Approximately 26% of patients revisited the ED during 1999–2011 and 5.1% did so within 30 days. Women had higher odds of a 30-day ED return after ED discharge than men (unadjusted odds ratio [uOR] = 1.26; 95% confidence interval [CI] 1.17–1.36). Time to first non-ED physician follow-up was shorter for girls (unadjusted hazard ratio [uHR] = 1.05; 95%CI 1.03–1.07) and women (uHR = 1.62; 95%CI 1.59–1.64) than for boys and men, respectively. Significant interactions between sex and age, socio-economic status, area of residence, and comorbidities were identified and changed the effect of sex on outcomes. Conclusions: In conclusion, women return to EDs within 30 days of discharge for acute asthma more often than men. Time to first non-ED physician follow-up for children and adults differed by sex. Multiple factors likely contribute to these differences; however, identifying these differences is critical to understand the influence of sex on health behaviors and outcomes.

KEYWORDS:

• Administrative databases
• asthma
• epidemiology
• sex differences

Declaration of interest

In the past 3 years, Dr. Rowe has been involved in primary research funded by Merck and, CEMPRA, and GlaxoSmithKline (GSK). He is not a member of any speaker's bureau or a paid consultant for any of these partners. The other authors declare no conflicts of interest.

Acknowledgements

The authors thank Alberta Health and Alberta Vital Statistics for facilitating access to the data. This study is based in part on data provided by Alberta Health. The interpretation and conclusions are contained herein are those of the researchers and do not necessarily represent the views of the Government of Alberta. Neither the government nor Alberta Health expresses any opinion in relation to this study.

Funding

The study was funded by an Innovation Grant from the Women & Children's Health Research Institute (www.wchri.org; Edmonton, Canada). During this work, Dr Rosychuk was salary supported by Alberta Innovates-Health Solutions (AIHS; Edmonton, Canada) as a Health Scholar. Dr Rowe is supported by Tier I Canada Research Chair in Evidence-based Emergency Medicine from the Canadian Institutes of Health Research (CIHR; Ottawa, Canada).