Risk factors for death from asthma

Background: Asthma mortality rates have increased in Canada and worldwide. Within Canada, the highest rates were seen in the prairie provinces. Objective: The objective was to determine risk factors for fatal asthma by comparing those who died of an acute exacerbation with those who attended a n emergency department for treatment of asthma. Methods: The case-control study included all deaths from asthma among those aged 5 to 50 years in Alberta, Saskatchewan and Manitoba from November, 19 92 through October, 1995 (cases). The 35 fatalities were matched to 209 con trols by age, gender, time of the index event and residence. Results: Cases were more likely than controls to have had severe asthma, an unscheduled physician visit in the past year, a past hospitalization for a sthma, and to have been intubated. Both groups reported frequent; regular a sthma symptoms. Beta-agonist bronchodilator use was more common among cases , as was use in excess of prescribed amounts. Use of inhaled steroids did n ot differ between groups. Prior to the index event controls were more likel y to report a cold or flu (OR = 0.27; 95% CI: 0.10 to 0.72) and that medica tions were "'not working" (OR = 0.30; 95% CI: 0.12 to 0.71). Cases were mor e often sad and depressed (OR = 2.88; 95% CI: 1.03 to 8.05). Time between o nset/recognition of symptoms and the event was significantly shorter for ca ses than controls. Conclusions: Both groups tolerated high levels of regular symptoms, suggest ing poor management. Opportunities for intervention existed for both groups near the time of the event. The short time between recognition of symptoms and death suggests patients at increased risk should monitor their conditi on closely and take action in response to predetermined criteria.