Severe asthma and adherence to peak flow monitoring: longitudinal assessment of psychological aspects.

Background: Adherence in severe asthma is a difficult health problem. Although psychosocial factors may be responsible for non-adherence, few longitudinal studies have investigated their link with adherence, with most studies having focused on pharmacology.

Methods: Sixty patients with severe asthma were recruited. Adherence was electronically monitored using peak flow measurements at entry and after 1 year of follow-up. Eysenck's Personality Inventory, Rotter's Locus of Control (LOC), and health control beliefs were all studied. Multiple logistic regression (MLR) was used for risk calculations.

Results: Initially, subjects with poor adherence had an external LOC (P=.001) and a high extraversion score (P=.003) compared to those with good adherence. The lie score was high in all patients. Nocturnal awakenings were highly significantly correlated with poor adherence (P=.006). After 1 year, patient adherence, extraversion, and neuroticism remained unchanged. The LOC changed in subjects with poor adherence, showing a less "external" orientation (P=.007). The health parameters were better at the end of the study. By MLR analysis, externality, extraversion, and low social desirability were associated with poor adherence. Patients with poor adherence had a greater probability of nocturnal symptoms.

Conclusion: No specific personality type was associated with lack of adherence in the present study, but a high extraversion score, a low social desirability score, and a high level of externality were all predictors of poor adherence.