Accelerometer-derived sleep metrics in mild and difficult-to-treat asthma

INTRODUCTION

Poor sleep health is associated with increased asthma morbidity and mortality. Accelerometers have been validated to assess sleep parameters though studies using this method in patients with asthma are sparse and none have compared mild to difficult-to-treat asthma populations.

METHODS

We performed a retrospective analysis from two recent in-house trials comparing sleep metrics between patients with mild and difficult-to-treat asthma. Participants wore accelerometers for 24-hours/day for seven days.

RESULTS

Of 124 participants (44 mild, 80 difficult-to-treat), no between-group differences were observed in sleep-window, sleep-time, sleep efficiency or wake time. Sleep-onset time was ~ 40 min later in the difficult-to-treat group (p = 0.019).

DISCUSSION

Broadly, we observed no difference in accelerometer-derived sleep-metrics between mild and difficult-to-treat asthma. This is the largest analysis of accelerometer-derived sleep parameters in asthma and the first comparing groups by asthma severity. Sleep-onset initiation may be delayed in difficult-to-treat asthma but a dedicated study is needed to confirm.

A Total Diet Replacement Weight Management Program for Difficult-to-Treat Asthma Associated With Obesity: A Randomized Controlled Feasibility Trial

BACKGROUND

Obesity is often associated with uncontrolled, difficult-to-treat asthma and increased morbidity and mortality. Previous studies suggest that weight loss may improve asthma outcomes, but with heterogenous asthma populations studied and unclear consensus on the optimal method of weight management. The Counterweight-Plus Programme (CWP) for weight management is an evidence-based, dietitian-led total diet replacement (TDR) program.

RESEARCH QUESTION

Can use of the CWP compared with usual care (UC) improve asthma control and quality of life in patients with difficult-to-treat asthma and obesity?

STUDY DESIGN AND METHODS

We conducted a 1:1 (CWP to UC) randomized, controlled single-center trial in adults with difficult-to-treat asthma and BMI of ≥ 30 kg/m2. The CWP was a 12-week TDR phase (800 kcal/d low-energy formula) followed by stepwise food reintroduction and weight loss maintenance for up to 1 year. The primary outcome was the change in Asthma Control Questionnaire 6 (ACQ6) score over 16 weeks. The secondary outcome was change in Asthma Quality of Life Questionnaire (AQLQ) score.

RESULTS

Thirty-five participants were randomized (36 screened) and 33 attended the 16-week follow-up (n = 17 in the CWP group, n = 16 in the UC group). Overall, mean ACQ6 score at baseline was 2.8 (95% CI, 2.4-3.1). Weight loss was greater in the CWP than UC group (mean difference, -12.1 kg; 95% CI, -16.9 to -7.4; P < .001). ACQ6 score improved more in the CWP than UC group (mean difference, -0.69; 95% CI, -1.37 to -0.01; P = .048). A larger proportion of participants achieved the minimal clinically important difference in ACQ6 score with CWP than with UC (53% vs 19%; P = .041; Number needed to treat, 3 [95% CI, 1.5-26.9]). AQLQ score improvement was greater in the CWP than UC group (mean difference, 0.76; 95% CI, 0.18-1.34; P = .013).

INTERPRETATION

Using a structured weight management program results in clinically important improvements in asthma control and quality of life over 16 weeks compared with UC in adults with difficult-to-treat asthma and obesity. This generalizable program is easy to deliver for this challenging phenotype. Longer-term outcomes continue to be studied.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03858608; URL: www.

CLINICALTRIALS

gov.

Physical activity levels in asthma: relationship with disease severity, body mass index and novel accelerometer-derived metrics

OBJECTIVES

Patients with asthma may feel limited in physical activity (PA). Reduced PA has been demonstrated in asthmatics versus healthy controls, and increasing PA associated with improved asthma outcomes. Obesity is commonly found with difficult-to-control asthma and worsens outcomes. We compared PA levels in participants with difficult-to-control asthma and elevated body mass index (BMI) (DOW group) and two mild-moderate asthma groups: one with BMI <25 kg/m² (MHW) and one with BMI ≥25 (MOW).

METHODS

This cross-sectional study used 7-day recordings from wrist-worn accelerometers to compare PA between groups. Inactive time, light (LPA), moderate-vigorous PA (MVPA) were measured, along with two novel metrics: intensity gradient (IG) reflecting PA intensity, and average acceleration (AA) reflecting PA volume. PA parameters were compared using ANOVA or Kruskall-Wallis testing. Correlation and linear regression analyses explored associations between PA parameters and asthma outcomes. As AA was the PA parameter correlated most closely with asthma-related outcomes, an exploratory analysis compared outcomes in highest and lowest AA quartiles.

RESULTS

75 participants were recruited; 57 accelerometer readings were valid and included in analysis. Inactive time was significantly higher (p < 0.001), and LPA (p < 0.007), MVPA (p < 0.001), IG (p < 0.001) and AA (p < 0.001) all significantly lower in DOW versus MHW and MOW groups, even after adjusting for age and BMI. Quartiles based on AA had significantly different asthma profiles.

CONCLUSIONS

Overweight/obese participants with difficult-to-control asthma performed less PA, and activity of reduced intensity and volume. Increased AA is associated with improvement in several asthma-related outcomes. Increased PA should be recommended to relevant patients.

Obesity affects type 2 biomarker levels in asthma

OBJECTIVE

Type 2 (T2) inflammation offers a therapeutic target for biologics. Previous trials suggest obesity influences T2-biomarker levels in asthma, though have not accounted for key variables, e.g. inhaled (ICS)/oral corticosteroid (OCS) use. We hypothesized that body mass index (BMI) would affect T2-biomarker levels, after adjusting for covariates.

METHODS

A retrospective analysis of data from two recent local trials of 153 participants with asthma (102 difficult-to-treat, 51 mild). Measurements included BMI, fractional exhaled nitric oxide (FeNO) and eosinophils. Correlation and regression analysis were performed for each biomarker to describe their relationship with BMI. Data was analyzed overall, and by asthma severity, T2-status and BMI tertile.

RESULTS

Increasing BMI was associated with reduction in FeNO when stratified by BMI tertile (25 ppb lowest tertile, 18 ppb highest tertile; p = 0.014). Spearmans rank showed a negative correlation between BMI and FeNO in difficult-to-treat asthma (ρ= -0.309, p = 0.002). Linear regression adjusting for sex, age, smoking, atopy, allergic/perennial rhinitis, ICS and OCS confirmed BMI as a predictor of FeNO overall (β= -2.848, p = 0.019). Eosinophils were reduced in the highest BMI tertile versus lowest in difficult-to-treat asthma (0.2x10⁹/L, 0.3x10⁹/L respectively; p = 0.02).

CONCLUSIONS

Increasing BMI is associated with lower FeNO in asthma when adjusted for relevant covariates, including steroid use. There also appears to be an effect on eosinophil levels. Obesity, therefore, affects T2 biomarker levels with implications for disease endotyping and determination of eligibility for biologic therapy. Whether this is due to masking of underlying T2-high status or development of a truly T2-low endotype requires further research.

A pragmatic randomised controlled trial of tailored pulmonary rehabilitation in participants with difficult-to-control asthma and elevated body mass index

Background

Difficult-to-control asthma associated with elevated body mass index (BMI) is challenging with limited treatment options. The effects of pulmonary rehabilitation (PR) in this population are uncertain.

Methods

This is a randomised controlled trial of an eight-week asthma-tailored PR programme versus usual care (UC) in participants with difficult-to-control asthma and BMI ≥ 25 kg/m2. PR comprised two hours of education and supervised exercise per week, with encouragement for two individual exercise sessions. Primary outcome was difference in change in Asthma Quality of Life Questionnaire (AQLQ) in PR versus UC groups between visits. Secondary outcomes included difference in change in Asthma Control Questionnaire-6 (ACQ6), and a responder analysis comparing proportion reaching minimum clinically important difference for AQLQ and ACQ6.

Results

95 participants were randomised 1:1 to PR or UC. Median age was 54 years, 60% were female and median BMI was 33.8 kg/m2. Mean  (SD) AQLQ was 3.9 (+/-1.2) and median (IQR) ACQ6 2.8(1.8–3.6). 77 participants attended a second visit and had results analysed. Median (IQR) change in AQLQ was not significantly different: 0.3 (− 0.2 to 0.6) in PR and − 0.1 (− 0.5 to 0.4) in UC, p = 0.139. Mean change in ACQ6 was significantly different: − 0.4 (95% CI − 0.6 to − 0.2) in PR and 0 (− 0.3 to + 0.3) in UC, p = 0.015, but below minimum clinically important difference. In ACQ6 responder analysis, minimum clinically important difference was reached by 18 PR participants (54.5%) versus 10 UC (22.7%), p = 0.009. Dropout rate was 31% between visits in PR group, and time to completion was significantly prolonged in PR group at 94 (70–107) days versus 63 (56–73) in UC, p < 0.001.

Conclusions

PR improved asthma control and reduced perceived breathlessness in participants with difficult-to-control asthma and elevated BMI. However, this format appears to be suboptimal for this population with high drop-out rates and prolonged time to completion.

Trial registration Clinicaltrials.gov. ID NCT03630432. Retrospectively registered, submitted May 26th 2017, posted August 14th 2018.

Bronchial reactivity to cigarette smoke; relation to lung function, respiratory symptoms, serum-immunoglobulin E and blood eosinophil and leukocyte counts

STUDY OBJECTIVES

The aim of the study was to investigate the relationship between the immediate bronchial response to inhaled cigarette smoke [cigarette smoke bronchial reactivity (CBR)] and lung function, respiratory symptoms and markers of allergy and inflammation.

DESIGN, PARTICIPANTS AND MEASUREMENTS

This cross-sectional study included 98 smokers. Their lung function and reversibility to inhaled terbutaline was measured. Their clinical history was obtained, an allergological examination was done, and bronchial reactivity to methacholine and inhaled cigarette smoke was measured. Questionnaires about respiratory symptoms, smoking history and drug usage were completed and a blood sample was obtained. Participants were divided into three groups: with asthma, chronic bronchitis and persons without asthma or chronic bronchitis (the respiratory healthy).

RESULTS

Forced expiratory volume in 1sec (FEV1) residuals were independently related to the % fall in FEV1 after 12 cigarette smoke inhalations (DFEV%) in all participants (P<001), in asthmatic smokers (P<0.01) and in smokers with chronic bronchitis (P<0.05). In smokers with asthma and chronic bronchitis FEV1 residuals explained 51% and 13% of the variation in DFEV%, respectively, but only 8% (P<0.05) and 1% (N.S.) of the variation in the methacholine bronchial reactivity. In the total population the presence of wheeze (P<0.01), attacks of breathlessness (P<0.05) and daily expectoration (P<0.001) were related to higher DFEV% readings. Serum immunonoglobulin (ES-IgE) was independently related to DFEV% in all participants (P<0.01), in smokers with chronic bronchitis (P<0.01) and in the respiratory healthy (0.05

CONCLUSION

Cigarette smoke bronchial reactivity was strongly associated to actual FEV1 in smokers with asthma and bronchitis, overall to most respiratory symptoms and in smokers without asthma to S-IgE. Cigarette smoke bronchial reactivity might be suitable to test further how cigarette smoke influences the pathophysiology of the bronchial wall, especially in smokers with asthma.

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MESH Headings

• Adult
• Aged
• Bronchial Hyperreactivity/etiology
• Bronchial Hyperreactivity/immunology
• Bronchial Hyperreactivity/physiopathology
• Cross-Sectional Studies
• Eosinophils/immunology
• Female
• Forced Expiratory Volume/physiology
• Humans
• Immunoglobulin E/blood
• Inflammation/immunology
• Leukocyte Count
• Leukocytes/immunology
• Male
• Methacholine Chloride
• Middle Aged
• Plants, Toxic
• Regression Analysis
• Smoke/adverse effects
• Smoking/adverse effects
• Smoking/immunology
• Nicotiana
• Vital Capacity/physiology

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Affiliation(s)

E J Jensen Department of Respiratory Diseases, University Hospital of Aarhus, Denmark
R Dahl
F Steffensen

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Bronchial reactivity to cigarette smoke in smokers: repeatability, relationship to methacholine reactivity, smoking and atopy

Bronchial reactivity to cigarette smoke (CBR) in a cross-section of 98 smokers has been investigated. All participants were subjects to skin-prick tests to common allergens, lung function measurements and bronchial challenges with methacholine and cigarette smoke. In 38 participants a rechallenge with cigarettes was performed 1 h after the first cigarette challenge. Lung function indices analysed were: forced expiratory volume in one second (FEV1); maximal expiratory flow at 75% of the forced vital capacity (MEF75%); and forced mid-expiratory flow between 25 and 75% of the forced vital capacity (FEF(25-75%)). All participants were tested for asthma and allergy, and were required to provide information regarding respiratory symptoms, first degree relatives with asthma and allergy and smoking habits. A substantial decrease was seen in all lung function indices after 12 cigarette-smoke inhalations, but only FEV1 was related to other variables. The maximal mean percentage fall in FEV1 was 10%, which was directly related to the number of inhalations (p<0.05). In multiple regression analyses the percentage fall in FEV1 was directly related to: FEV1/vital capacity (VC) (p<0.01); to the asthmatic/bronchitic status (p<0.05); and to the accumulated and standardized cigarette consumption (p<0.05). The percentage fall in FEV1 bore no relationship to methacholine bronchial reactivity, sex or age and had a continuous distribution. The repeat challenge showed a smaller fall in FEV1 compared to the first challenge after 12 cigarette smoke inhalations (p<0.05). The percentage fall in FEV1 correlated after the first and the repeat challenge (p<0.05). Repeatability of the challenge could not be determined in this study because of tachyphylaxis. Bronchial reactivity to cigarette smoke is a tobacco smoke-specific bronchial response. All participants responded and the response showed a continuous distribution. Bronchial reactivity to cigarette smoke may be of importance for symptoms and prognosis in chronic bronchitis and chronic obstructive pulmonary disease and should be studied in relation to the degree of accelerated lung function loss in smokers and other cigarette induced lung abnormalities.

Bronchial reactivity to cigarette smoke in smokers: repeatability, relationship to methacholine reactivity, smoking and atopy

Bronchial reactivity to cigarette smoke (CBR) in a cross-section of 98 smokers has been investigated. All participants were subjects to skin-prick tests to common allergens, lung function measurements and bronchial challenges with methacholine and cigarette smoke. In 38 participants a rechallenge with cigarettes was performed 1 h after the first cigarette challenge. Lung function indices analysed were: forced expiratory volume in one second (FEV1); maximal expiratory flow at 75% of the forced vital capacity (MEF75%); and forced mid-expiratory flow between 25 and 75% of the forced vital capacity (FEF(25-75%)). All participants were tested for asthma and allergy, and were required to provide information regarding respiratory symptoms, first degree relatives with asthma and allergy and smoking habits. A substantial decrease was seen in all lung function indices after 12 cigarette-smoke inhalations, but only FEV1 was related to other variables. The maximal mean percentage fall in FEV1 was 10%, which was directly related to the number of inhalations (p<0.05). In multiple regression analyses the percentage fall in FEV1 was directly related to: FEV1/vital capacity (VC) (p<0.01); to the asthmatic/bronchitic status (p<0.05); and to the accumulated and standardized cigarette consumption (p<0.05). The percentage fall in FEV1 bore no relationship to methacholine bronchial reactivity, sex or age and had a continuous distribution. The repeat challenge showed a smaller fall in FEV1 compared to the first challenge after 12 cigarette smoke inhalations (p<0.05). The percentage fall in FEV1 correlated after the first and the repeat challenge (p<0.05). Repeatability of the challenge could not be determined in this study because of tachyphylaxis. Bronchial reactivity to cigarette smoke is a tobacco smoke-specific bronchial response. All participants responded and the response showed a continuous distribution. Bronchial reactivity to cigarette smoke may be of importance for symptoms and prognosis in chronic bronchitis and chronic obstructive pulmonary disease and should be studied in relation to the degree of accelerated lung function loss in smokers and other cigarette induced lung abnormalities.