Developments in asthma incidence and prevalence in Alberta between 1995 and 2015

Abstract

Background: Asthma is a chronic respiratory disease characterized by reversible bronchoconstriction and airway inflammation. According to Statistics Canada in 2014, 8.1% of Canadians aged 12 and older reported having asthma diagnosed by a health care professional. Therefore, in 2014 there were an estimated 274,661 persons with asthma in Alberta. Most epidemiological studies estimate prevalence and incidence using survey-based data, which has limitations. The Ontario Asthma Surveillance Information System (OASIS) group has developed and validated an algorithm for epidemiologic asthma studies using provincial health databases. In Alberta, there are some studies using provincial databases, but most are restricted to Emergency Department visits and do not represent the entire asthma population. Using the validated asthma definition for epidemiologic studies, we performed an analysis of the Alberta Health administrative databases to investigate and report province-wide asthma prevalence, incidence and mortality in Alberta from 1995 to 2015. Methods: Data from administrative databases, provided by Alberta Health, was analyzed to determine age and sex specific prevalence, incidence and mortality of the asthma population. The population cohort was all individuals residing in the province of Alberta, ages 0 to 99 from 1995-2015. Kendall’s Tau coefficient test was used to ascertain whether the observed trends were statistically significant. Results: Between 1995 and 2015, the age-standardized incidence of asthma decreased by more than 50% in both males and females. Prevalence; however, increased 3-fold over the 20 years for both genders from 3.9% to 12.3% (Tau=1.00, p<0.0001) in females and from 3.5% to 11.6% (Tau=1.00, p<0.0001) in males. Thus, in 2015 there were 496,927 people with asthma in Alberta. All-cause mortality in the asthma population decreased over time, in both females (Tau=-0.71, p<0.0001) and males (Tau=-0.69, p=0.0001). For the last several years, all-cause mortality was higher in those with asthma. There were ~7 deaths/1000 in the population with asthma versus ~5 deaths/1000 in those without asthma. Conclusions: The incidence of asthma decreased in both females and males while prevalence continued to increase, but at a slower rate than previously. All-cause mortality in asthma patients was higher than in those without asthma, but both decreased over time.

An inverse relationship between asthma prevalence and medication dispensation trend: a 12-year spatial analysis of electronic health record data in Alberta, Canada

“…While there are standard recommendations and guidelines for the diagnosis and treatment of asthma, patients living with this disease often experience poor health-related quality of life [3] and continue to experience exacerbations [4]. Apart from the increasing air pollution, rapid urbanization, and a growing trend in marijuana and vaping, particularly among the adolescents [5][6][7][8], poor patient adherence to asthma medications is a major contributing factor to these outcomes [9][10][11][12]. Despite efforts to change this narrative through patient and physician education [13][14][15], it is well reported that adherence to treatment in asthma is varied, with rates of <50% in children [16] and 30-70% in adults [1,17].…”

A Preliminary Spatial Analysis of the Association of Asthma and Traffic-Related Air Pollution in the Metropolitan Area of Calgary, Canada

“…As of 2018, approximately 12% of Canadians (i.e., 3 million people) and 12% of Albertans have been diagnosed with asthma [3,4]. Asthma prevalence is increasing in Alberta [5], where the asthma incidence rate was highest in children aged 1 to 14 [6]. Children are more susceptible to asthma onset, likely a result of a less developed immune system, smaller lung passages, increased exposure to outdoor pollutants, and increased pollutant inhalation per body weight [7].…”