Medication beliefs, adherence, and outcomes in people with asthma: The importance of treatment beliefs in understanding inhaled corticosteroid nonadherence-a retrospective analysis of a real-world data set.

Background: Poor adherence to inhaled corticosteroids (ICSs) increases asthma morbidity and mortality and is influenced by patients' treatment beliefs. This study maps patients' beliefs about ICSs across 6 countries examining variations in beliefs, and their relationship with adherence and outcomes. Objective: We sought to explore the relationship between patient treatment beliefs, and adherence and outcomes in asthma across 6 countries. Methods: Patients 18 years or older with asthma, receiving ICS alone or in combination with a long-acting ß2-agonist, were included from a point-in-time paper survey of patients with asthma in Europe and the United States. Clinical characteristics, such as adherence and asthma control, were collected by self- and physician-report. Patients completed the Beliefs about Medicines Questionnaire, adapted for ICSs. Relationships between patient treatment beliefs, adherence, and outcomes were examined using regression analyses. Results: Data from 1312 patients were analyzed. Patients were from Germany (24%), the United States (21%), France (21%), Spain (16%), Italy (10%), and the United Kingdom (9%). Most had physician-reported mild-intermittent asthma (87%), and mean age was 40 ± 15.5 years. There was considerable variation in necessity beliefs between countries, with respondents in Italy having more doubts about treatment necessity and respondents in Spain showing higher concerns. Patients with doubts about ICS necessity and high concerns had lower self-reported (necessity: χ2(2) = 34.31, P < .001; concerns: χ2(2) = 20.98, P < .001) and physician-reported adherence (necessity: χ2(2) = 11.70, P = .003; concerns: χ2(2) = 34.45, P < .001). Patients with high necessity beliefs (F(2, 483) = 3.33; P = .037) and high concerns (F(2,483) = 23.46; P < .001) reported poorer control. Physician estimates of adherence did not correlate well with patient self-report (ρ = 0.178, P < .001). Conclusions: ICS necessity beliefs and concerns were associated with adherence and asthma control. This has implications for the design of adherence interventions.