Correlation between perceived asthma control and thoraco-abdominal asynchrony in primary care patients diagnosed with asthma.

Objective: Thoraco-abdominal asynchrony (TAA), the discordant movement of the abdomen and thorax, may impact upon health-related variables. Here, we investigated the extent to which TAA is associated with health-related variables, particularly perceived asthma control and quality of life.

Methods: Ambulatory respiratory data from 43 patients diagnosed with asthma and 43 healthy age and sex-matched controls were recorded over 4 hours. Phase relation (Ph Rel Total), the percentage of time that the effects of rib cage (RC) and diaphragmatic movement result in opposite effects on intra-thoracic volume, quantified TAA. Subjects completed the Mini Asthma Quality of Life Questionnaire (AQLQ), Asthma Control Questionnaire (ACQ), Nijmegen questionnaire (NQ), Hospital Anxiety and Depression Scale (HADS), Spielberger State-Trait Anxiety Inventory (STAI), and General Health Perception (GHP) subscale of the short form 36 questionnaire'. Capnography profiling, breath-hold time (BHT), and standard spirometry were performed.

Results: The time in asynchrony was significantly greater in the asthma than in the healthy control group (Ph Rel Total = 14% (interquartile range (IQR) 8.5-20.7%) versus 10.4% (IQR 7.1-14.5%), p = .012). In patients with asthma, Ph Rel Total was weakly associated with poorer ACQ scores (r = 0.33, p = .03), and in the healthy control group with GHP (r = 0.319, p = .037). Post-hoc exploratory analysis revealed a moderate relationship in the female asthma subgroup between Ph Rel Total and AQLQ (r = -0.56, p = .003).

Conclusions: TAA may be associated with decreased perceived asthma control. In healthy individuals, asynchrony may be associated with low perception of general health. Further studies are required to investigate if the reduction of TAA improves these health-related variables.