Applicable predictive factors extracted from peak flow trajectory for the prediction of asthma exacerbation

BACKGROUND

Real-time asthma exacerbation prediction and acute asthma attack detection are essential for patients with severe asthma. Peak expiratory flow (PEF) exhibits a potential for use in long-term asthma self-monitoring. However, the method for processing PEF calculations remains to be clarified.

OBJECTIVE

To develop clinically applicable novel exacerbation predictors calculated using PEF records.

METHODS

Previously proposed exacerbation predictors, including the slope of PEF, percentage predicted PEF, percentage best PEF, the highest PEF over the lowest PEF within specific periods, and PEF coefficient of variation, in addition to a novel indicator delta PEF moving average (ΔMA), defined as the difference between 14-day and 3-day average PEF values, along with moving average (MA) adjusted for PEF reference (%ΔMA), were verified using the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma data of 127 patients with severe asthma from whom 73,503 PEF observations were obtained. Receiver operating characteristic curves for all predictors were drawn, and the corresponding areas under the curve (AUCs) were computed. Regression analysis for MA and percentage MA were conducted.

RESULTS

The most outstanding performance was shown by ΔMA and %ΔMA, with AUC values of 0.659 and 0.665 in the univariate model, respectively. When multivariate models were incorporated with random intercepts for individual participants, the AUC for ΔMA and %ΔMA increased to 0.907 and 0.919, respectively.

CONCLUSION

The MA and percentage MA are valuable indicators that should be considered when deriving predictors from the PEF trajectory for monitoring exacerbations in patients with severe asthma.

TRIAL REGISTRATION

The Hokkaido-based Investigative Cohort Analysis for Refractory Asthma was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN ID: 000003254). https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000003917.

Relationships of computed tomography-based small vessel indices of the lungs with ventilation heterogeneity and high transfer coefficients in non-smokers with asthma

Background: The mechanism of high transfer coefficients of the lungs for carbon monoxide (Kco) in non-smokers with asthma is explained by the redistribution of blood flow to the area with preserved ventilation, to match the ventilation perfusion. Objectives: To examine whether ventilation heterogeneity, assessed by pulmonary function tests, is associated with computed tomography (CT)-based vascular indices and Kco in patients with asthma. Methods: Participants were enrolled from the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) study that included a prospective asthmatic cohort. Pulmonary function tests including Kco, using single breath methods; total lung capacity (TLC), using multiple breath methods; and CT, were performed on the same day. The ratio of the lung volume assessed using single breath methods (alveolar volume; V_A) to that using multiple breath methods (TLC) was calculated as an index of ventilation heterogeneity. The volume of the pulmonary small vessels <5 mm² in the whole lung (BV5 volume), and number of BV5 at a theoretical surface area of the lungs from the plural surface (BV5 number) were evaluated using chest CT images. Results: The low V_A/TLC group (the lowest quartile) had significantly lower BV5 number, BV5 volume, higher BV5 volume/BV5 number, and higher Kco compared to the high V_A/TLC group (the highest quartile) in 117 non-smokers, but not in 67 smokers. Multivariable analysis showed that low V_A/TLC was associated with low BV5 number, after adjusting for age, sex, weight, lung volume on CT, and CT emphysema index in non-smokers (not in smokers). Conclusion: Ventilation heterogeneity may be associated with low BV5 number and high Kco in non-smokers (not in smokers). Future studies need to determine the dynamic regional system in ventilation, perfusion, and diffusion in asthma.

Blood eosinophil count variability in chronic obstructive pulmonary disease and severe asthma

BACKGROUND

Blood eosinophils are essential biomarkers that vary substantially over time in patients with COPD and asthma. However, no study has identified the changes and effects in the changes of the blood eosinophil counts over time in both diseases. This study aimed to demonstrate blood eosinophil variability in patients with COPD and severe asthma based on these backgrounds.

METHODS

A total of 172 patients with COPD from the Hokkaido COPD cohort study and 96 patients with severe asthma from the Hokkaido Severe Asthma Cohort Study, whose blood eosinophil counts were measured annually over a 3-year period, were analyzed. The factors contributing to consistently high or low blood eosinophil counts were examined in each cohort. The stability of the eosinophil classification (<150, 150-299, ≥300 cells/μL) was compared based on the number of asthma-like features in patients with COPD and the smoking status in patients with severe asthma.

RESULTS

Among all the patients, the most stable range of baseline blood eosinophil counts differed between the two diseases, with <150 cells/μL in COPD and ≥300 cells/μL in severe asthma. In COPD, the number of asthma-like features (bronchodilator reversibility, blood eosinophilia, and atopy) affects the blood eosinophil count variation patterns. In severe asthma, smoking status did not affect the blood eosinophil count variation patterns.

CONCLUSIONS

We identified variations in the blood eosinophil counts and their contributing factors in patients with COPD and severe asthma.

Differential role of mucus plugs in asthma: Effects of smoking and association with airway inflammation

BACKGROUND

The physiological importance of mucus plugs in computed tomography (CT) imaging is being increasingly recognized. However, whether airway inflammation and smoking affect the association between mucus plugs and clinical-physiological outcomes in asthma remains to be elucidated. The objective of this study is to examine how airway inflammation and/or smoking affect the correlation of CT-based mucus plug scores with exacerbation frequency and airflow limitation indices in asthma.

METHODS

A total of 168 patients with asthma who underwent chest CT and sputum evaluation were enrolled and classified in eosinophilic asthma (EA; n = 103) and non-eosinophilic asthma (NEA; n = 65) groups based on sputum eosinophil percentage (cut-off: 3%). The mucus plug score was defined as the number of lung segments with mucus plugs seen on CT.

RESULTS

More mucus plugs were detected on CT scans in the EA group than in the NEA group, regardless of smoking status. Mucus plug score and exacerbation frequency during one year after enrollment were significantly associated in the EA group but not in the NEA group after adjusting for demographics, blood eosinophil count, and fractional exhaled nitric oxide. Mucus plug score was associated with percentage of predicted forced expiratory volume in 1 s in non-smoking individuals in the EA and NEA group and in smoking individuals in the EA group but not in the NEA group after adjusting for demographics.

CONCLUSIONS

The association of mucus plug score with exacerbation frequency and reduced lung function may vary due to airway inflammatory profile and smoking status in asthma.

Association of longitudinal changes in quality of life with comorbidities and exacerbations in patients with severe asthma

BACKGROUND

Quality of life (QoL) assessment is important in the management of severe asthma, and comorbidities and/or exacerbations may affect longitudinal QoL. However, there are few reports on the longitudinal assessment of QoL in patients with asthma over multiple years and its related factors. This study aimed to clarify the relationship of longitudinal changes in QoL with comorbidities and/or exacerbations during a prolonged observation period in patients with severe asthma.

METHODS

A total of 105 subjects who participated in the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) with a six-year follow-up were analyzed. QoL was assessed annually, using the Standardized Asthma Quality of Life Questionnaire, and the subjects were divided into three groups: (1) persistently good QoL, (2) persistently poor QoL, and (3) fluctuating QoL. Assessed comorbidities comprised depression, gastroesophageal reflux disease, and excessive daytime sleepiness (EDS), a key symptom of obstructive sleep apnea.

RESULTS

Of 105 subjects with severe asthma, 53 (50%) were classified in the persistently good QoL group, 10 (10%) in the persistently poor QoL group, and 42 (40%) in the fluctuating QoL group. The persistently poor QoL group was associated with shorter time to hospitalization due to exacerbation and the presence of multiple comorbidities. In addition, the presence of EDS was an independent contributor to the fluctuating QoL group compared to the persistently good QoL group.

CONCLUSIONS

The presence of multiple comorbidities and hospitalization due to exacerbation contribute to longitudinal changes in QoL in patients with severe asthma.

Further evidence for association of YKL-40 with severe asthma airway remodeling

BACKGROUND

The chitinase-like protein YKL-40 is associated with airflow limitation on spirometry and airway remodeling in patients with asthma. It remains unclear whether YKL-40 is associated with morphologic changes in the airways and parenchyma or with future progression of airflow limitation in severe asthma.

OBJECTIVE

To evaluate the association of circulating YKL-40 levels with morphologic changes in the airways and parenchyma and with longitudinal progression of airflow limitation.

METHODS

The patients were participants in the Hokkaido Severe Asthma Cohort Study (n = 127), including smokers. This study consisted of 2 parts. In analysis 1, we analyzed associations between circulating YKL-40 levels and several asthma-related indices, including computed tomography-derived indices of proximal wall area percentage, the complexity of the airways (airway fractal dimension), and the parenchyma (exponent D) cross-sectionally (n = 97). In analysis 2, we evaluated the impact of circulating YKL-40 levels on forced expiratory volume in 1 second (FEV₁) decline longitudinally for a 5-year follow-up (n = 103).

RESULTS

Circulating YKL-40 levels were significantly associated with proximal wall area percentage and airway fractal dimension (r = 0.25, P = .01; r = -0.22, P = .04, respectively), but not with exponent D. The mean annual change in FEV₁ was -33.7 (± 23.3) mL/y, and the circulating YKL-40 level was a significant independent factor associated with annual FEV₁ decline (β = -0.24, P = .02), even after controlling for exponent D (β = -0.26, P = .01).

CONCLUSION

These results provide further evidence for the association of YKL-40 with the pathogenesis of airway remodeling in severe asthma.

Case Report: Hereditary Fibrosing Poikiloderma With Tendon Contractures, Myopathy, and Pulmonary Fibrosis (POIKTMP) Presenting With Liver Cirrhosis and Steroid-Responsive Interstitial Pneumonia

Background: Hereditary fibrosing poikiloderma with tendon contractures, myopathy, and pulmonary fibrosis (POIKTMP) is an extremely rare disease caused by mutations in FAM111B, and only approximately 30 cases have been reported worldwide. Some patients develop interstitial pneumonia, which may lead to progressive pulmonary fibrosis and poor prognosis. However, no effective treatment for interstitial pneumonia associated with POIKTMP has been reported. Here, we report an autopsy case of POIKTMP, wherein interstitial pneumonia was improved by corticosteroids.

Case Presentation: A 44-year-old Japanese man was referred to our hospital due to poikiloderma, hypotrichosis, and interstitial pneumonia. He developed progressive poikiloderma and muscle weakness since infancy. He also had tendon contractures, short stature, liver cirrhosis, and interstitial pneumonia. Mutation analysis of FAM111B revealed a novel and de novo heterozygous missense mutation, c.1886T > G (p(Phe629Cys)), through which we were able to diagnose the patient with POIKTMP. 3 years after the POIKTMP diagnosis, interstitial pneumonia had worsened. After 2 weeks of administrating 40 mg/day of prednisolone, his symptoms and lung shadows improved. However, he subsequently developed severe hepatic encephalopathy and eventually died of respiratory failure due to bacterial pneumonia and pulmonary edema. Autopsy revealed an unclassifiable pattern of interstitial pneumonia, as well as the presence of fibrosis and fatty degeneration in several organs, including the liver, kidney, skeletal muscle, heart, pancreas, and thyroid.

Conclusions: We report a case of POIKTMP in which interstitial pneumonia was improved by corticosteroids, suggesting that corticosteroids could be an option for the treatment of interstitial pneumonia associated with this disease.

Clinical Characteristics of Patients and Factors Associated with Switching Biologics in Asthma

Purpose

Biologics have been used increasingly for the treatment of severe asthma. However, established guidelines for the selection, switching, or discontinuation of biologics do not exist. We aimed to identify the clinical characteristics of patients with asthma who required switching biologics and the factors associated with switching biologics.

Patients and Methods

This was a retrospective study of 42 patients with severe asthma treated with biologics at the Hokkaido University Hospital between 23^rd June 2016 and 30^th April 2021, when two biologics were available in Japan. We compared the characteristics of subjects who continued and switched biologics. The time to switch the biologics was assessed by type 2 inflammatory biomarkers, pulmonary function indices, and the presence of comorbidities, including the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) score and aspirin exacerbated respiratory diseases (AERD), using the Kaplan–Meier method and a multivariate Cox proportional hazards model.

Results

Eight and five patients were treated by mepolizumab and benralizumab at baseline, respectively among the 31% (13/42) who switched the biologics. Subjects who required switching biologics were characterized by high blood eosinophil counts, younger age, JESREC scores of 11 points or higher, and AERD. The time taken to switch biologics was significantly shorter in the subgroups with high JESREC scores (≥11) or AERD, compared with their counterparts with low JESREC scores or without AERD (both, P < 0.05). JESREC scores of ≥11, but not the presence of AERD, were associated with time to switch biologics.

Conclusion

The presence of eosinophilic chronic rhinosinusitis based on JESREC scores of ≥11 and younger age were factors associated with switching biologics in asthma.

[A CASE OF SEVERE ASTHMA RESULTING IN DISEASE EXACERBATION AFTER PROLONGATION OF THE DOSING INTERVAL AFTER LONG-TERM OMALIZUMAB ADMINISTRATION]

At the time of writing of this manuscript, four biologics were clinically available for the treatment of severe asthma, and there were no established recommendations for the period of administration or timing of discontinuation of each biologic. We present a case of severe asthma that was well controlled with long-term omalizumab treatment; however, prolongation of the dosing intervals resulted in disease exacerbation that was refractory to omalizumab treatment despite the restoration of the recommended interval of administration. We suspect that the prolonged dosing intervals might have reduced the efficacy of omalizumab. We report this case because dosing intervals should be considered in clinical practice in cases of long-term omalizumab treatment.

[A CASE OF SEVERE ASTHMA SWITCHED TO MEPOLIZUMAB DUE TO LATE-OCCURRING UNRESPONSIVENESS TO BENRALIZUMAB]

We report the case of a 66-year-old patient with severe asthma complicated by eosinophilic chronic rhinosinusitis (ECRS). The patient was initially treated with benralizumab, which resulted in marked improvement of asthma symptoms and reduced the peripheral blood eosinophil count to 0/μL. Additionally, oral steroids were discontinued. After 7 months of benralizumab administration, the asthma symptoms worsened and peripheral blood eosinophil count increased to 813/μL. The neutralizing antibodies to benralizumab may have resulted in the recurrence of symptoms due to eosinophilic inflammation. The nasal symptoms, on which benralizumab had an unremarkable effect, improved when treatment was switched to mepolizumab. However, the difference in effects of biologics on ECRS has not been elucidated and warrants further investigation. To the best of our knowledge, this is the first report of a case of severe asthma in which mepolizumab administration reversed the clinical deterioration of asthma, which was possibly caused by neutralizing antibodies to benralizumab.