Treatment compliance, passive smoking, and asthma control: a three year cohort study.

AIMS To study the role of treatment compliance and parents' smoking on asthma control in children with recently diagnosed mild or moderate persistent asthma who were prescribed inhaled anti-inflammatory treatment. METHODS Prospective cohort study of 167 children aged 6-12 years (64% boys). Patients were examined at inclusion and followed up for three years with a visit every four months. Peak expiratory flow (PEF) was measured twice a day during the week before each visit. Two control criteria were monitored: (1) symptom control = having diurnal or nocturnal exacerbations less than once a week and no symptoms between exacerbations, at all visits; and (2) PEF control = daily PEF variability <20% on each of the seven days before each visit. RESULTS Symptom control was achieved by 25.1% of children and PEF control by 53.3%. Symptom control was positively related to having understood the way in which the medication worked and taking the prescribed doses (odds ratios (OR) = 3.38 and 4.82 respectively). It was inversely related to smoking within the home (OR = 0.34). PEF control was positively related to taking the prescribed doses (OR = 3.58). It was less frequently achieved if the mother smoked within the home (OR = 0.34). CONCLUSIONS Results suggest that, to maximise the benefits of available asthma medication and to improve health outcomes, further efforts should be made to convince the parents of asthmatic children not to smoke in the house, and to improve compliance by increasing the patients' understanding of the disease and its treatment.