- Design
- Individual participant data meta-analysis of trials and cohort studies
- Population
- 7,161 people with asthma across five datasets
- Primary outcome
- Future severe asthma attacks and response to anti-inflammatory therapy
- Effect
- ACQ-5 per 0.5 points: aRR 1.09 (95% CI 1.06–1.12)
This individual-patient meta-analysis combined control-group data from 22 randomised trials (6,513 people) with four further datasets, totalling 7,161 people with asthma of varying severity. It asked whether symptom burden on the five-item Asthma Control Questionnaire (ACQ-5) predicts severe attacks or response to anti-inflammatory treatment.
ACQ-5 scores did not consistently align with lung function or inflammation. Each 0.5-point rise was associated with only a 9% increase in attack rate (aRR 1.09), adding little to a model without it. ACQ-5 did not change the benefit of mepolizumab. In contrast, patients with both high blood eosinophils and high FeNO had the largest reduction in attacks (aRR 0.38).
Symptoms matter to patients, but they are a weak guide to future risk. Using biomarkers alongside symptoms gives a better basis for escalating anti-inflammatory treatment.
- Do not judge future attack risk from symptom scores alone.
- Check a blood eosinophil count in patients with uncontrolled or attack-prone asthma.
- Use FeNO where available to identify type 2 inflammation.
- Consider biologic referral for frequent attacks with raised eosinophils and FeNO.
Why it matters
Escalating treatment on symptoms alone can both miss high-risk patients and over-treat low-risk ones.
Don't overread it
Symptoms still matter for quality of life; this is about predicting attacks.
The statistics, in plain English
A rate ratio of 1.09 per half-point means symptoms carry only slight prognostic weight. The R² change of 0.02 means adding ACQ-5 to other predictors barely improved the model. Biomarker findings came from a smaller set of datasets.
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