Perceived barriers to exercise in patients
We assessed the perceived barriers to exercise in patients with difficult asthma under the care of a tertiary clinical service to create a better real-life understanding of relevant limiting factors. To the best of our knowledge, this is the first study to explore this in patients with difficult asthma. Although differences were seen in OCS and rates of hospitalisation, our patient group was generally comparable to the WATCH Cohort as a whole, and representative of a typical group of patients with difficult asthma. Patient perceptions of barriers to exercise in difficult asthma were high. The median score within our cohort were comparable to those found in patients with cardiovascular disease and much higher than those seen in patients with cancer . The distribution of scores was wide throughout the cohort, suggesting that perceived barriers to exercise are patient specific, possibly reflecting the heterogeneity of difficult asthma. Identification of values of low, medium and high scores for the ETBQ have not been identified, but may be useful to identify in the future.
There did not appear to be significant differences between sex of the patient and perceived barriers to exercise. This contrasts with a previous study which investigated perceived barriers to exercise in a cohort of university students with disabilities. This study demonstrated that the most significant barriers to exercise were interpersonal in nature and that females were more likely to experience higher interpersonal barriers . It may be that within our difficult asthma patient group, the disease related barriers to exercise were great enough to balance out any sex specific barriers.
The lack of correlation with frequency of hospitalisations is interesting, suggesting that exacerbations on a background of reasonable day to day control may impact less on perceptions of barriers to exercise than a constant level of poor control with few exacerbations. This may be of relevance to prescribing criteria for biological treatments, which, at present focus on exacerbation frequency .
BMI impacts perceived barriers to exercise
There was a significant difference for Q1 score in BMI categories, as identified by the overall Kruskall Wallis test. The post-hoc pairwise comparisons were not significant. However, this was probably due to a lack of statistical power due to small group sizes. This effect of BMI on perceived barriers to exercise is noteworthy, but not a wholly unexpected finding as differences between BMI and barriers to physical activity have previously been demonstrated in young Australian males . Patients with asthma who are obese have a greater symptom burden and lose more days to illness than non-obese asthma patients . This population are more likely to benefit from exercise interventions to address both obesity and asthma driven inflammation [33, 34]. It is therefore important to adapt current exercise interventions to make them more accessible to this group of patients, potentially with classes available for this group of patients specifically to help alleviate concerns around others’ perceptions, and psychological and dietician support alongside this. Understanding that perceived barriers to exercise differ for obese patients with asthma is the essential first step in doing this. Further work investigating the specific causes of pain in these patients is now important. The lack of correlation between BMI and overall perceived barriers to exercise is interesting. It may be that the majority of the perceived barriers to exercise in obese patients is related to pain, but overall the perception of barriers to exercise was not increased by a BMI. BMI is a gross measure of obesity, and noted to be overestimated in those with high muscle mass. This may add further ambiguity to results, and investigation of bioimpedence data would perhaps give further clarification.
Differentially perceived barriers to exercise dependent on age of diagnosis
In this present study, significantly different perceptions on the effect of asthma to barriers to exercise were demonstrated between groups based on age of diagnosis. Those whose disease started between the ages of 6–11 were more likely to see their disease as a barrier to exercise than those diagnosed under 5 years old. This appears to be a key stage for engagement in sport in later life, with a report from The Women in Sport Research group showing that if children start to drop out of sporting activities at this age then they tend not to re-engage as adults . Comparatively, exercise levels in children at age 7 are not reduced in those with a diagnosis of asthma . It may be that diagnosis at this age compounds the effects of this transition point. Diagnosis at this age may result in a higher dropout rate from physical activity which continues into adulthood. This could partly explain some of the lower levels of activity seen in patients with asthma compared to the general population. Targeted interventions in this age group may go some way to ameliorating this effect .
Perceived symptom burden impacts perceived barriers to exercise
A high perceived symptom burden as assessed through the symptom scores (ACQ6) and number of rescue courses of OCS were found to significantly correlate with an increased perceived barrier to exercise. Correlations between a perceived high barrier to exercise therapy and disease specific assessments are reflective of the literature. Those with more severe disease have previously been shown to view exercise as more likely to be detrimental . Both these measures of symptom burden are partially subjective. ACQ scores reflect patient interpretation of their symptoms over the preceding week. Furthermore, rescue courses of OCS are often started by patients as part of a rescue pack on the basis of deteriorating symptoms. However, in this present research, objective asthma specific markers of severity such as lung function and markers of Type 2 high disease did not correlate with perceived barriers to exercise. Similarly, a cross-sectional analysis of physical activity in the UK millennium cohort demonstrated that activity levels in children with asthma were not affected by the severity of their disease . This is a clinically relevant finding which suggests that severity of disease is not necessarily a barrier to exercise. This has been supported by our pilot work , and that of others , investigating exercise intervention in asthma patients. This suggests that high levels of biological disease are not necessarily a barrier to adoption of exercise for some patients. This data is of use for reassuring both patients and clinicians that exercise intervention is safe in asthma regardless of disease severity.
Psychological co-morbidity in the form of a high HADS Anxiety, depression and total scores also correlated significantly with a higher perceived barriers to exercise score. A meta-analysis has previously identified low mood and stress as two of the most significant barriers to exercise in mental illness . However, exercise has also been demonstrated to improve mood associated with reduction in depression-associated inflammation in COPD  and in health . A similar pattern has been seen with QoL where exercise specific self-efficacy has been shown to correlate with health related QoL in COPD . Therefore, our results which show that a higher barrier to exercise correlates with a lower QoL score are not unexpected. Exercise is, however, known to improve health related QoL in asthma [4, 23] and therefore interventions to address this paradox need investigating.
Challenges and considerations
There are limitations to this study. Firstly, the strength of correlations throughout were low-moderate; this was likely a result of the numbers who completed the questionnaire. Secondly, a questionnaire format will not provide as detailed or accurate information as a qualitative interview format. However, there are advantages to a questionnaire format, in that participants may be more honest with regards to barriers to exercise than they would be with a face-face interviewer. Furthermore, a questionnaire format reduces time demands on patients and clinical staff both in a research and clinical context, whilst still providing noteworthy findings, which could then potentially be expanded on in a qualitative way. The ETBQ was the most specific questionnaire available at the time of conception of this study to address the question of perceived barriers to exercise within the context of a chronic disease, thus this questionnaire was chosen to be used.
With regards to other limitations, asthma symptoms can fluctuate and the clinical data was not necessarily collected at the same time as the ETBQ. However, the clinical data which most closely aligned temporally with the ETBQ data was extracted from the database to reduce any inaccuracies. Also, questionnaires were completed at different stages of enrolment in the WATCH study; some at baseline, and others at follow up visits. Similarly, perceived patient barriers to exercise may change depending on the day of the exercise, and this may not be captured by a single time point questionnaire. There were a few significant differences between the WATCH cohort and the ETBQ sub-cohort, including number of rescue courses of OCS in the last 12 months, which was higher in the WATCH cohort as a whole. This may partly explain the only borderline significance of the correlation between ETBQ total score and OCS rescue courses. Besides this, the ETBQ cohort was representative of the wider WATCH population and there was no difference between those who completed the questionnaire compared to those who did not, suggesting this was not a bias to taking part in the ETBQ study. The ETBQ focuses on a prescribed activity and yet some patients within the cohort were not prescribed any activity. If this were the case, then they were asked to complete the questionnaire from the perspective of what prevents them from exercising rather than the burden of any prescribed exercise. However, misunderstanding of this may explain why only 62 of the 90 participants invited to complete the ETBQ fully completed the questionnaire. With any self-reported questionnaire-based research, there is always the concern of responder bias. However, patients were asked to complete the questionnaire regardless of whether they undertook regular exercise. This removed any expectation that they should be taking part in exercise.