Table 2 Intervention by the doctor – instruction manual (summary)

This will consist of a maximum 3 minutes of advice in which the health professional explains clearly to the smoker that the most effective step they could take to improve their health would be to stop smoking and provides them background information in writing. The same material will be provided to all patients and consists of two leaflets on the benefits of stopping smoking (the leaflets being those provided by the Department of Health of the Basque Government and routinely used in primary care consultations for brief anti-smoking interventions).

In the event of spirometry detecting airway obstruction (post-bronchodilator FEV1/FVC < 70%), the patient will be told that they have chronic obstructive pulmonary disease secondary to smoking and that it is very important that they stop their habit.

In the event of spirometry values being within the normal range, the patient will be told that their respiratory function is not yet impaired and that it would be a good moment to give up smoking.

In the event of a restrictive spirometry pattern, the patient will be told that they have impaired pulmonary function and they will be provided usual care.

In all cases, the doctor should address any concerns or queries of the patient concerning the spirometry or any other issues that arise during the consultation.