Asthma is a chronic inflammatory disorder of the airways in the lungs. In people with asthma, the airways become inflamed and obstructed, usually because they are hyperresponsive to internal and external factors, commonly called triggers (e.g., allergens, irritants). People with asthma typically experience difficulty breathing, shortness of breath, chest tightness, wheezing (a whistling sound produced in the airways during breathing), sputum (mucus) production, and/or cough. These symptoms can be episodic or persistent. As with many chronic conditions, the cause of asthma is not known with certainty, but it is thought to develop from interactions between genetic and environmental factors such as a family history of asthma and exposure to smoke, air pollution, or occupational vapours or particles. When asthma appears in adulthood, an estimated 10% to 25% of cases are work related.
Asthma is one of the most common chronic conditions in Canada. In Ontario, it is estimated that more than 2 million people were living with asthma in 2016/17. In recent years, the incidence of asthma in Ontario (the number of people newly diagnosed each year) has been decreasing across all age groups; it dropped from nearly 10 new cases per 1,000 people in 1996/97 to 2.45 per 1,000 in 2016/17. At the same time, because people are generally living longer, the prevalence of asthma in Ontario (the number of people living with the disease) continued to increase for all ages; it rose from around 90 per 1,000 people in 1996 to 155 per 1,000 in 2016/17. Both incidence and prevalence vary substantially across the province; in 2016/17, both were highest in the Central West region and lowest in the Waterloo Wellington region.
Although asthma has no cure, most people can control their asthma by using appropriate controller medications, such as inhaled corticosteroids, and reducing their exposure to triggers. The primary goal of asthma care is to help people achieve and maintain asthma control, which reduces their risk of having an exacerbation (a flare-up or asthma attack) and improves their overall health and quality of life. Current guidelines stress that, with appropriate management in primary care, most people with asthma should be able to live symptom free. Exacerbations requiring oral corticosteroids, an emergency department visit, or hospitalization should usually be considered a failure of asthma management. Every asthma death should be considered preventable.
However, it is estimated that 50% of people with asthma in Canada have uncontrolled disease, resulting in unnecessary reductions in quality of life and avoidable illness and deaths. In Ontario, about 85 people die from asthma each year (1,272 deaths from 2000 to 2015). The age- and sex-adjusted all-cause mortality rate for people living with asthma remains higher than for the population overall (in 2008, there were 852 deaths per 100,000 people with asthma vs. 640 per 100,000 in the general population).
Uncontrolled asthma also contributes to high health care use and costs. Overall use of health services for people with asthma has been shown to be much higher for people with uncontrolled asthma and particularly high in the year prior to asthma-related deaths. Among people aged 15 years and older in Ontario in 2016/17, there were 21,886 asthma-specific emergency department visits and 8,393 asthma-specific hospitalizations.
Asthma is also associated with substantial indirect costs to society, such as absenteeism from school and work. The economic burden of asthma in Ontario (direct health care costs plus indirect social costs) was estimated at $1.8 billion in 2011.
These data highlight opportunities for improving the management of asthma in primary care and community-based care settings. This standard focuses on helping clinicians diagnose asthma appropriately, recognize and address uncontrolled asthma, escalate and taper medication optimally, empower people with asthma to self-manage using an asthma action plan, and support safe, effective transitions in care. Improving the quality of asthma care can help people better control their disease, preventing acute exacerbations, emergency department visits, hospital admissions, and deaths.