The main aim of the study is to evaluate the adherence to controller inhalation medication in asthma and Chronic Obstructive Pulmonary Disease (COPD) in Universitair Ziekenhuis Brussel. Adherence will be assessed using the 12-question Test for the Adherence to Inhalers (TAI) yielding a score indicating level of adherence (high, intermediate or poor). The TAI also provides some indication about the possible mechanisms of non-adherence (sporadic, deliberate or unconscious). The aim of the study is also to compare the adherence between the 2 study subgroups (asthma and COPD patients). Several other factors which could influence the compliance of the patients will also be evaluated: age, sex, pack years, FEV1 (Forced Expiratory Volume 1), exacerbation history, symptom control, type of inhaler and number of inhalers. By identifying different patient and treatment characteristics that lead to non-adherence, future education efforts could be better targeted to these patients presenting the most important unmet need in terms of adherence.

Adherence to the controller inhalation medication is an important component of asthma and COPD care. Good adherence to the prescribed medication is asthma patients is associated with better symptom control and improved lung function. Also, lower exacerbation rate and mortality risk, less healthcare utilisation, lower healthcare-associated costs and a better quality of life are linked with better adherence in asthma and COPD patients.

However, studies have shown that the adherence to therapy in chronically ill patients averages around 50%. In asthma patients the level of adherence varies between 30-70%, while compliance rate in COPD patients is around 20-60% (though the numbers vary). Adherence in asthma and COPD patients is thus generally low.

Adherence in these patients is measured in studies in different ways: electronic device monitoring, dispensing data, drug levels or several self-administered questionnaires, among others. Each technique has its own benefits and drawbacks. However, the easiest to use are the self-administered questionnaires. Although many of these exist, a particularly interesting questionnaire is the TAI (Test for the Adherence to Inhalers). It exists in 2 versions: a 10-question and a longer 12-question test. The 12 question TAI has 2 added questions, in which a healthcare professional evaluates the use of the inhaler by the patient. All 12 questions can then be used to identify different non-compliance behavioural patterns. The advantages of this questionnaire are therefore that it can be used for both asthma and COPD patients, that it is designed specifically for inhalation medication and that it not only measures adherence but also the type of non-compliance .

The main aim of the study is thus to evaluate the adherence to controller inhalation medication in asthma and COPD in Universitair Ziekenhuis Brussel. Adherence will be assessed using the 12-question TAI (Test for the Adherence to Inhalers). The aim of the study is also to compare the adherence between the 2 study subgroups (asthma and COPD patients). Several other factors which could influence the compliance of the patients will also be evaluated: age, sex, pack years, FEV1, exacerbation history, symptom control, type of inhaler and number of inhalers. By identifying different patient and treatment characteristics that lead to non-adherence, future education efforts could be better targeted to these patients presenting the most important unmet need in terms of adherence.

Patient recruitment will take place at the Universitair Ziekenhuis Brussel respiratory outpatient clinic. Before their scheduled appointment, patients they will be screened to participate in the study. Recruitment will start January 2019 until March 2019, or until the target number of patients is reached. On the day of their appointment, the participants will receive all necessary information about the study and the informed consent process from the principal investigator.

Patients will have sufficient time to reflect on their participation in this study and to ask questions. After obtaining the written informed consent from the patients, the necessary interventions (filling in questionnaires and gathering information from the patients files) will take place.

It will be allowed for the patients to provide informed consent and to participate in the study on a later date.

Statistical analysis:

The statistical analysis will be conducted in 3 steps :

1. Preliminary one-way ANOVA to evaluate the dependent variable (TAI level of adherence) for each independent variable.
2. A multi-way ANOVA model will be constructed to include the relevant independent variables and potential two-way interactions, by maximization of adjusted R2 obtained through a backward elimination in order to correct for multicollinearity.
3. In a final step, the model residuals will be checked to satisfy the normality condition through application of the Kolmogorov-Smirnov and Shapiro-Wilk tests, also exploring the influence of potential heteroscedasticity.

Inclusion Criteria:

• Asthmatics with treatment ≥ GINA step 2.
• COPD-patients , GOLD stage II-IV.

Exclusion Criteria:

• No spirometry results available.
• COPD patients not on long-acting bronchodilators.

Choice made with regards to the current General Data Protection Regulation in Europe.