Asthma presentations by adults to emergency departments in Alberta, Canada: a large population-based study

Abstract

Background: Asthma is a widespread disease with a prevalence of approximately 7 to 10% in adults. Exacerbations are common in the emergency department (ED) setting. The objective of this study was to describe the epidemiology of asthma presentations to EDs made by adults in the province of Alberta, Canada.

Methods: The Ambulatory Care Classification System of Alberta and provincial administrative databases were used to obtain all ED encounters for asthma during 6 fiscal years (April 1999 to March 2005). Information extracted included demographics, ED visit timing, and subsequent visits to non-ED settings. Data analysis included descriptive summaries and directly standardized visit rates.

Results: There were 105,813 ED visits for asthma made by 48,942 distinct adults, with an average of 2.2 visits per individual. Most patients (66%) had only one asthma-related ED visit. Female patients (61.2%) presented more commonly than male patients. The gender- and age-standardized visit rates declined from 9.7/1,000 in 1999/2000 to 6.8/1,000 in 2004/2005. The welfare and Aboriginal subsidy groups had larger age-specific ED visits rates than other populations. Important daily, weekly, and monthly trends were observed. Hospital admission occurred in 9.8% of the cases; 6.4% had a repeat ED visit within 7 days. Overall, 67.4% of individuals had yet to have a non-ED follow-up visit by 1 week. The estimated median time to the first follow-up visit was 19 days (95% confidence interval, 18 to 21).

Conclusions: Asthma is a common presenting problem in Alberta EDs, and further study of these trends is required to understand the factors associated with the variation in presentations. The important findings include an overall decrease in the rates of presentation over the study period, disparities based on age, gender, and socioeconomic/cultural status, and the low rate of early follow-up. Targeted interventions could be implemented to address specific groups and reduce asthma-related visits to Alberta EDs.