A population-based study of emergency department presentations for asthma in regions of Alberta

Acuity of asthma exacerbations in Alberta, Canada is increasing: a population-based study

BACKGROUND

Asthma is a common respiratory illness affecting 2.8 million Canadians, including 9.7% of Albertans. Prior studies showed a substantial decrease in ED visits for asthma in the decade preceding 2010, followed by a stabilization. This was attributed to improvements in the pharmacologic and non-pharmacologic treatments for asthma during that period followed by a balance between epidemiologic drivers and protective factors in the population.

METHODS

We assessed whether this trend continued in Alberta from 2010 to 2022 using population level data for the volume of daily ED visits, acuity of asthma exacerbations in the ED, and hospitalization rate.

RESULTS

The mean number of ED visits decreased from 4.5 to 2.2 per million persons per day, but the acuity of exacerbations and the proportion requiring hospitalization increased. The number of patients presenting with the highest level of acuity increased by over 300%, and the percentage of patients requiring hospitalization increased from 6.8 to 11.3%.

CONCLUSION

Total ED visits for asthma exacerbations continues to decline in Alberta. The reasons for an increase in more severe exacerbations requires further attention.

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

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 threefold 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, although at a slower rate than previously. All-cause mortality in asthma patients was higher than in those without asthma, but both decreased over time.

Association between allergic rhinitis and asthma in a Northern Alberta cohort

Background

Many published epidemiologic studies confirm a marked increase in the prevalence of asthma and allergic rhinitis. The link between allergic rhinitis and asthma has been extensively studied and approximately 75% of patients with asthma have allergic rhinitis. The proportion of patients with asthma in populations of allergic rhinitis patients has not been well studied.

Objective

The purpose of this study is to estimate the prevalence of undiagnosed asthma in a specific population of patients presenting to an Otolaryngologist with symptoms of allergic rhinitis.

Study design

Prospective cohort study. Methods: Patients presenting with symptoms of allergic rhinitis to two tertiary care Rhinology practices in Northern Alberta were asked to undergo allergy skin testing, serum IgE quantification, and pulmonary functional testing. Patients with previous asthma screening or known history of reactive airway disease or asthma were excluded.

Results

107 patients with allergic rhinitis symptoms were recruited between September 2010 to January 2013. Patients predominantly had perennial or persistent rhinitis (64.5%) with moderate-severe symptoms (50.5%). While only 14.9% of patients had abnormal IgE levels, 68.8% had positive skin testing. Abnormal pulmonary function tests were obtained in 39.1% of patients and 26.1% of patients were diagnosed with asthma.

Conclusions

There is a high prevalence of undiagnosed asthma in patients presenting to tertiary Rhinology care with moderate to severe allergic rhinitis symptoms. Screening lung function testing should be considered in this patient population.

Respiratory distress syndrome at birth is a risk factor for hospitalization for lower respiratory tract infections in infancy

BACKGROUND

Respiratory distress syndrome (RDS) and hospitalization for lower respiratory tract infection (LRTI; specifically, respiratory syncytial virus) are important causes of morbidity in infancy. Whether RDS at birth is an independent risk factor for LRTI is unknown. This study estimated the risk of LRTI-related hospitalization among late preterm infants with a history of RDS.

METHODS

The population-based cohort from Québec included all late preterm infants (32-36 weeks gestational age) born in 1996 to 1997. RDS was identified by International Classification of Diseases, Ninth Revision code 769, and a comparison cohort generated from all without RDS. A multivariable model estimated the adjusted odds ratio of LRTI-related hospitalization among late preterm infants with a history of RDS; and the incidence and increased risk of childhood chronic respiratory morbidity was calculated.

RESULTS

Of the 7488 late preterms, 459 (6.1%) had a history of RDS; 525 late preterms (7.0%) were hospitalized for LRTI in infancy, including 57 (12.4%) with RDS. The adjusted odds ratio for LRTI-related hospitalization associated with RDS was 1.6 (1.2-2.2). Other significant risk factors included male sex, or diagnosis of other respiratory conditions, diaphragm anomalies, bacteremia, intraventricular hemorrhage, congenital heart disease or respiratory system anomalies. Late preterm infants with a history of RDS were also at a significantly increased risk of childhood chronic respiratory morbidity.

CONCLUSIONS

Late preterms with a history of RDS are at a 60% increased risk of LRTI-related hospitalization in infancy compared with late preterm infants without RDS. Such infants may benefit from interventions decreasing the risk of contracting respiratory viruses causing acute LRTI.