Magnitude of effect of asthma treatments on Asthma Quality of Life Questionnaire and Asthma Control Questionnaire scores: Systematic review and network meta-analysis.
BACKGROUND
The Asthma Quality of Life Questionnaire (AQLQ) and the Asthma Control Questionnaire (ACQ) are widely used in asthma research; however, in studies of newer asthma treatments, mean improvements in these measures compared with placebo arms do not exceed the minimal important difference (MID), particularly when a new treatment is added to current treatment.


OBJECTIVE
We performed a systematic review and network meta-analysis to examine the magnitude of AQLQ and ACQ responses achieved with commonly used asthma drugs and factors influencing these end points in clinical trials.


METHODS
A systematic literature search was conducted to identify blinded randomized controlled trials reporting AQLQ or ACQ results. Mixed treatment comparisons, combined with meta-regression, were then performed.


RESULTS
Of the 64 randomized controlled trials (42,527 patients) identified, 54 included the AQLQ and 11 included the ACQ as end points. The presence of a run-in period, the nature of treatment during the run-in period, concurrent treatment during the treatment period, and instrument version significantly influenced the change in AQLQ score from baseline and whether it exceeded the MID. When compared with placebo, only inhaled corticosteroids (ICSs), with or without a long-acting β-agonist, achieved the MID. The ACQ results were comparable with those of the AQLQ: no differences from placebo exceeded the MID, and ICS-based treatments provided the greatest improvements.


CONCLUSIONS
The established within-patient MID for the ACQ and AQLQ is not achievable as a group-wise efficacy threshold between treatment arms in clinical studies in which controllers are added to ICS treatment. Thus in addition to reporting mean changes of the instruments, other measurement criteria should be considered, including responder analyses.
Department of Medicine, University of Cape Town, Cape Town, South Africa. Electronic address: Eric.Bateman@uct.ac.za.
Eric D
ED
Bateman
Global Health Economics and Outcomes Research, Boehringer Ingelheim GmbH, Ingelheim am Rhein, Germany.
Dirk
D
Esser
RTI Health Solutions, Research Triangle Park, NC.
Costel
C
Chirila
RTI Health Solutions, Research Triangle Park, NC.
Maria
M
Fernandez
Clinical Research, Boehringer Ingelheim Ltd, Bracknell, United Kingdom.
Andy
A
Fowler
TA Respiratory Diseases, Boehringer Ingelheim GmbH, Ingelheim am Rhein, Germany.
Petra
P
Moroni-Zentgraf
Lung Centre, Gordon and Leslie Diamond Health Care Centre, Vancouver, British Columbia, Canada.
J Mark
JM
FitzGerald
D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000328:Adult; D000818:Animals; D001249:Asthma / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
D000305:Adrenal Cortex Hormones
Asthma; asthma control; network meta-analysis; quality of life; questionnaire