ASTHMA CONTROL QUESTIONNAIRE (ACQ)
International guidelines for the treatment of asthma have identified that the primary clinical goal of asthma management is to optimise asthma control (minimisation of symptoms, activity limitation, bronchoconstriction and rescue β2 -agonist use) and thus reduce the risk of life-threatening exacerbations and long-term morbidity. The Asthma Control Questionnaire (ACQ) was developed to meet these criteria. It measures both the adequacy of asthma control and change in asthma control, which occurs either spontaneously or as a result of treatment.
Initially, all questions that might be important for the assessment of asthma control were identified. They included day and nighttime symptoms, activity limitations, airway calibre and rescue bronchodilator use. Ninety-one asthma clinicians in 18 countries, who were currently on international asthma guideline committees or who were experts on asthma measurement, selected the most important questions for the assessment of asthma control. The top 5 symptoms were: woken at night by symptoms, wake in the mornings with symptoms, limitation of daily activities, shortness of breath and wheeze. The clinicians indicated that the optimum measure of airway calibre was FEV1% predicted pre-bronchodilator and that daily rescue bronchodilator use should be included.
The ACQ has 7 questions (the top scoring 5 symptoms, FEV1% pred. and daily rescue bronchodilator use). Patients are asked to recall how their asthma has been during the previous week and to respond to the symptom and bronchodilator use questions on a 7-point scale (0=no impairment, 6= maximum impairment). Clinic staff score the FEV1% predicted on a 7-point scale. The questions are equally weighted and the ACQ score is the mean of the 7 questions and therefore between 0 (totally controlled) and 6 (severely uncontrolled).
The ACQ has strong measurement properties and has been fully validated for use in both clinical practice and clinical trials. For clinical practice, clinical trials and epidemiological studies, the ACQ has strong discriminative and evaluative properties which means that it can detect small differences between patients with different levels of asthma control and it is very sensitive to within-patient change in asthma control over time.
The ACQ is able to identify the adequacy of asthma control in individual patients. In general, patients with a score below 1.0 will have adequately controlled asthma and above 1.0 their asthma will not be well controlled. However, there is a very grey area between 0.75 and 1.25 where patients are on the borderline of adequate control. On the 7-point scale of the ACQ, a change or difference in score of 0.5 is the smallest that can be considered clinically important. This means that changes of 0.5 or greater would justify a change in the patient’s treatment (in the absence of undue side effects or excessive costs). This may vary a little between individual patients.
The original ACQ validation studies were all conducted in adults 17 years or older.
When the original ACQ was developed, twenty asthma paediatricians were among the clinicians who participated in the selection of questions for the ACQ and the items they chose were almost the same as those chosen by clinicians looking after adult patients. Therefore, it was considered that the questions in the adult ACQ would have content validity for assessing asthma control in children. Initial cognitive debriefing studies provided evidence that children 11 years and older could understand the instructions, questions and response options of the self-administered version of the adult ACQ accurately and unaided. Children 10 years and younger needed help. Therefore we have developed an interviewer-administered version of the adult ACQ for children 6-10 years. The children respond to the questions themselves (not the parent or caregiver) and it must be administered by a trained interviewer. Full instructions for administering the questionnaire to children are provided with the questionnaire. The ACQ has been fully validated for all children 6-17 years when the self-administered adult version is used by children 11 years and older and the interviewer-administered version is used for children 6-10 years. The ACQ has not been validated in children less than 6 years of age.
The full 7-question ACQ should be used whenever possible. Extensive research has shown that the components of asthma control (daytime symptoms, nighttime symptoms and airway calibre) are not closely correlated with each other. If one or more of the questions in the ACQ are omitted, there is a risk of estimating asthma control inaccurately in individual patients. For instance, a patient with inadequate control may be missed if they have poor perception of airway narrowing and the FEV1 question is omitted.
It is not always possible to measure FEV1. We have a version of the ACQ with peak expiratory flow instead of
FEV1 but this version is not quite so accurate as the original. However, it is better to use PEF than no measure of airway calibre at all. The ACQ with PEF is supplied on specific request only.
Long-acting beta agonists may sometimes be used as both regular and rescue medication making the estimate of rescue use difficult and inaccurate. Rescue bronchodilator use correlates quite closely with symptoms and so omitting this question is not as serious as omitting the airway calibre question.
If either the airway calibre or rescue bronchodilator questions cannot be answered, it is better to use one of the shortened versions of the ACQ than no measurement at all. (Symptoms alone, symptoms + bronchodilator, symptoms + FEV1). For large clinical trials and epidemiological surveys, shortened versions of the ACQ have shown good measurement properties but not quite so good as those of the complete 7 question version.
- Juniper EF, O’Byrne PM, Guyatt GH, Ferrie PJ, King DR. Development and validation of a questionnaire to measure asthma control. Eur Respir J 1999; 14: 902-7.
- Juniper EF, Svensson K, Mörk AC, Ståhl E. Measurement properties and interpretation of three shortened versions of the asthma control questionnaire. Respir Med 2005; 99: 553-8.
- Juniper EF, Bousquet J, Abetz L, Bateman ED. Identifying ‘well-controlled’ and ‘not well-controlled’ asthma using the Asthma Control Questionnaire. Respir Med 2006; 100: 616- 621.
- Juniper EF, Gruffydd-Jones K, Ward S, Svensson K. Validation, measurement properties and interpretation of the Asthma Control Questionnaire in children. Eur Respir J 2010: 36: 1410-1416.
English for North America (adult versions).
English for the United Kingdom (children's interviewer-versions)
Paper: Self-administered (Interviewer - children only)
Various electronic devices
OBTAINING THE ACQ
Asthma Control Questionnaire (ACQ) | Asthma Control Diary (ACD)