EPI-ASTHMA study protocol: a population-based multicentre stepwise study on the prevalence and characterisation of patients with asthma according to disease severity in Portugal

Prevalence and Characterisation of Patients with Asthma According to Disease Severity in Portugal: Findings from the EPI-ASTHMA Pilot Study

Objective

To assess the feasibility of the procedures of EPI-ASTHMA. EPI-ASTHMA is a population-based multicentre stepwise study about the prevalence and characterisation of patients with asthma based on disease severity in Portugal.

Methods

A pilot study of EPI-ASTHMA was conducted with adults from three primary care centres. We followed a stepwise approach comprising 4 stages: stage 0-invitation phone call (n ~1316); stage 1-telephone interview (n ~658); stage 2-clinical assessment with physical examination, diagnostic tests, and patient-reported outcome measures, to confirm the diagnosis of those with possible asthma at stage 1 (n ~160); stage 3-characterization of a subgroup of asthma patients by collecting data through a telephone interview, patient file review and CARATm app (n ~40), after 3-months. The frequency of asthma was calculated in relation to the entire study population (stage 1) and the frequency of difficult-to-treat/severe asthma in relation to the number of asthma patients (stage 3).

Results

From 1305 adults invited, 892 (68%) accepted to participate (stage 0) and 574 (64%; 53[42-67] y; 43% male) were interviewed (stage 1). From those, 148 (26%; 60[46-68] y; 43% male) were assessed at stage 2, and 46 (31%; 51[39-67] y; 44% male) were diagnosed with asthma. Half of these patients (n = 23) accepted to install the app. Stage 3 was completed by 41 (93%) patients, of whom 31 (83%) had asthma confirmed by their file review. A total of 8% of participants had asthma, of those 17% had difficult-to-treat and 5% severe asthma.

Conclusion

Attained recruitment rates and the quality of the results confirmed the feasibility of the EPI-ASTHMA stepwise approach. This pilot study provided insight into the improvement of the procedures to be generalized across the country.