The Extra Cost Due to Non-Adherence to Inhaled Treatments in Adolescents with Mild-to-Moderate Persistent Asthma

Abstract

A 12-month estimation of the economic impact of non-adherence to inhalation treatments in adolescents with mild-to-moderate atopic asthma. Non-smoking adolescents aged 12-19 years, without any significant comorbidity, prescribed with inhaled cortico-steroids (ICS) or ICS/long-acting beta(2)-adrenergics (LABA) via dry powder inhalers (DPIs) on a regular basis were automatically selected from the institutional database. Spirometric lung function, clinical outcomes, and pharmacological information were collected. The adolescents' adherence to their prescribed regimen was calculated monthly. Adolescents were divided in two sub-groups based on their adherence to prescriptions: ≤70% (not adherent) or >70% (adherent), and statistically compared (Wilcoxon test, assuming p < 0.05). Overall, 155 adolescents fulfilled the inclusion criteria (males, 49.0%; mean age, 15.6 years ± 2.9 SD; mean BMI, 19.1 ± 1.3 SD). Mean values of lung function were: FEV1 = 84.9% pred. ± 14.8 SD, FEV1/FVC = 87.9 ± 12.5 SD; MMEF = 74.8% pred. ± 15.1 SD and V25 = 68.4% pred. ± 14.9 SD. ICS had been prescribed in 57.4% of subjects and ICS/LABA in 42.6%. Mean adherence to original prescriptions was 46.6% ± 9.2 SD in non-adherent and 80.3% ± 6.6 SD in adherent adolescents, respectively (p < 0.001). The mean rates of hospitalizations, exacerbations, and GP visits; the average duration of absenteeism; the frequency of systemic steroids and antibiotics courses needed over the study period were significantly and substantially lower in adolescents adherent to prescriptions (all p < 0.001). The mean total annual extra cost calculated in the two sub-groups was EUR 705.8 ± 420.9 SD in non-adherent adolescents and EUR 192.1 ± 68.1 SD in adherent adolescents, respectively (p < 0.001), which was 3.7 times higher than in non-adherent adolescents. In adolescents, the clinical control of mild-to-moderate atopic asthma is directly and strictly related to the degree of adherence to prescribed inhalation therapies. All clinical and economic outcomes prove dramatically poor when adherence is low, and treatable asthma can be frequently mistaken for refractory asthma in these cases. Adolescents' non-adherence impacts the burden of the disease quite substantially. Much more effective strategies centered specifically on adolescents' asthma are needed.