Bridging the gap in asthma management among adolescents and young adults

Abstract

Background: Asthma can develop at any age. During childhood, the prevalence of asthma is higher in boys, but after puberty it grows higher in girls. The goals of asthma treatment are to achieve and maintain asthma control and to reduce future risks of exacerbations. Most children with asthma have a mild or moderate disease. However, a small proportion have severe asthma. Patients with severe asthma have the largest disease burden and require more healthcare resources than those with mild-to-moderate asthma. In adolescence, asthma management involves a transition from pediatric to adult healthcare, meaning that changes in care and pharmacological treatment may occur.

Aim: The overall research aim of this thesis was to characterize asthma in adolescence and young adulthood, with a particular focus on sex and severity, and to identify factors of importance for improved asthma management during the transition from pediatric to adult healthcare.

Methods: All four studies in this thesis were based on the ongoing Swedish population-based birth cohort BAMSE (Barn/Child, Allergy, Milieu, Stockholm, Epidemiology). This birth cohort includes 4,089 participants, followed from infancy up to age 24 years. Information about symptoms and treatment related to asthma and other allergic diseases were assessed through repeated questionnaires. At ages 4, 8, 16 and 24 years, the participants were also invited to undergo a clinical examination including for example blood sampling and measurements of lung function, height, and weight. To address the specific aims in this thesis, BAMSE data were linked to data from national and regional registers for asthmarelated healthcare consumption and dispensed medications. In addition, qualitative data were obtained through individual interviews.

Results: In Study I, 14% fulfilled the study definition of asthma at 16 years of age (15% among females vs. 13% among males, p = 0.22). Almost half had uncontrolled asthma (46%). In total, 24% (n = 104) of the adolescents with asthma were dispensed high daily doses of inhaled corticosteroids (ICS) or fixed combinations of ICS and long-acting β2-agonists within the preceding 18 months. This was more common among males than females (29% vs. 19%, p = 0.02). Moreover, 7% (n = 24) had severe asthma (6% of females vs. 7% of males, p = 0.61). In Study II, four categories emerged based on the young adults’ experiences of their asthma healthcare: “I have to take responsibility,” “A need of being involved,” “Feeling left out of the system,” and “Lack of engagement.” The young adults felt they were given more responsibility, did not know where to turn, and had fewer follow-ups in adult healthcare. Further, the participants wanted healthcare providers to involve them in self-management already during adolescence, and felt that their asthma received insufficient attention from healthcare providers. In Study III, 8% (n = 147) had persistent asthma. Among those with persistent asthma, register data showed that 39% (58 of 147) had at least 1 healthcare consultation within the 4- year period preceding their 18th birthday and 37% (55 of 147) in the 4-year period following that date. The mean number of healthcare consultations in the 4-year period preceding age 18 years was 1.6, compared with 1.0 in the 4-year period after age 18 years (p = 0.02). At least 1 dispensation of any ICS before age 18 years was found for 73% (107 of 147), compared with 50% (74 of 147) after age 18 years. On average, the participants with persistent asthma were dispensed ICS 3.1 times in the 4-year period preceding age 18 years and 2.1 times in the 4- year period after age 18 years (p < 0.01). Only 3% of the persistent subjects (5 of 147) had a regular dispensation of any ICS once a year during the 8-year period. In Study IV, a latent class analysis was performed, and a 4-class solution of asthma trajectories was identified: never/infrequent (n = 3,291, 80%), early-onset transient (n = 307, 8%), adolescent-onset (n = 261, 6%), and persistent asthma (n = 230, 6%). Uncontrolled asthma was equally prevalent in the adolescent-onset and persistent asthma trajectory groups, at both 16 (42% vs. 42%, p = 0.90) and 24 years of age (54% vs. 52%, p = 0.81). The persistent asthma trajectory group had a higher proportion of eosinophil counts ≥ 0.3 (109 cells/L) at 24 years of age compared with the adolescent-onset trajectory group (31% vs. 19%, p < 0.01).

Conclusion: Based on the results from this thesis, it could be concluded that asthma was common in adolescence and young adulthood, and a shift from male to female dominance occurred during adolescence. Further, many adolescents and young adults had few asthmarelated healthcare consultations and dispensed asthma medications. Moreover, the adolescents and young adults with more recent onset of disease had equal burdens of respiratory markers as those who had persistent symptoms.