Effects of allergen and trigger factor avoidance advice in primary care on asthma control: a randomized-controlled trial.

Background: Allergy contributes significantly to asthma exacerbation, yet avoidance of triggers, in particular allergens, is rarely addressed in detail in regular asthma review in primary care.

Objective: To determine whether structured, individually tailored allergen and trigger avoidance advice, given as part of a primary care asthma review, improves lung function and asthma control.

Methods: In a randomized-controlled trial 214 adults with asthma in six general practices were either offered usual care during a primary care asthma review or usual care with additional allergen and trigger identification (by skin prick testing and structured allergy assessment) and avoidance advice according to a standardized protocol by trained practice nurses. Main outcome measures were lung function, asthma control, asthma self-efficacy.

Results: Both intervention groups were equivalent in demographic and asthma-related variables at baseline. At 3-6-month follow-up, patients receiving the allergen and trigger avoidance review showed significant improvements in lung function (assessed by blinded research nurses) compared with those receiving usual care. Significantly more patients in the intervention group than in the control group showed improvements in forced expiratory volume in 1 s > or =15%. No significant differences were found in self-report measures of asthma control. Asthma-specific self-efficacy improved in both groups but did not differ between groups.

Conclusions: Allergen and trigger identification and avoidance advice, given as part of a structured asthma review delivered in primary care by nurses results in clinically important improvements in lung function but not self-report of asthma control.

Trial Registration: ISRCTN45684820.