Nationwide survey of refractory asthma with bronchiectasis by inflammatory subtypes

• Research
• Open Access
• 
  

• Natsuko Nomura, 
• Hisako Matsumoto, 
• Akihito Yokoyama, 
• Yoshihiro Nishimura, 
• Koichiro Asano, 
• Akio Niimi, 
• Yuji Tohda, 
• Norihiro Harada, 
• Hiroyuki Nagase, 
• Makoto Nagata, 
• Hiromasa Inoue, 
• Mitsuko Kondo, 
• Takahiko Horiguchi, 
• Nobuaki Miyahara, 
• Nobuyuki Hizawa, 
• Masayuki Hojo, 
• Noboru Hattori, 
• Naozumi Hashimoto, 
• Akira Yamasaki, 
• Toru Kadowaki, 
• Tomoki Kimura, 
• Mari Miki, 
• Hirokazu Taniguchi, 
• Mikio Toyoshima, 
• Tetsuji Kawamura, 
• Osamu Matsuno, 
• Yoko Sato, 
• Hironobu Sunadome, 
• Tadao Nagasaki, 
• Tsuyoshi Oguma, 
• Toyohiro Hirai on behalf of 
• the BEXAS study

Respiratory Research volume 23, Article number: 365 (2022) 

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Abstract

Rationale

Bronchiectasis and bronchiolitis are differential diagnoses of asthma; moreover, they are factors associated with worse asthma control.

Objective

We determined clinical courses of bronchiectasis/bronchiolitis-complicated asthma by inflammatory subtypes as well as factors affecting them.

Methods

We conducted a survey of refractory asthma with non-cystic fibrosis bronchiectasis/bronchiolitis in Japan. Cases were classified into three groups, based on the latest fractional exhaled NO (FeNO) level (32 ppb for the threshold) and blood eosinophil counts (320/µL for the threshold): high (type 2-high) or low (type 2-low) FeNO and eosinophil and high FeNO or eosinophil (type 2-intermediate). Clinical courses in groups and factors affecting them were analysed.

Results

In total, 216 cases from 81 facilities were reported, and 142 were stratified: 34, 40 and 68 into the type 2-high, -intermediate and -low groups, respectively. The frequency of bronchopneumonia and exacerbations requiring antibiotics and gram-negative bacteria detection rates were highest in the type 2-low group. Eighty-seven cases had paired latest and oldest available data of FeNO and eosinophil counts; they were analysed for inflammatory transition patterns. Among former type 2-high and -intermediate groups, 32% had recently transitioned to the -low group, to which relatively low FeNO in the past and oral corticosteroid use contributed. Lastly, in cases treated with moderate to high doses of inhaled corticosteroids, the frequencies of exacerbations requiring antibiotics were found to be higher in cases with more severe airway lesions and lower FeNO.

Conclusions

Bronchiectasis/bronchiolitis-complicated refractory asthma is heterogeneous. In patients with sputum symptoms and low FeNO, airway colonisation of pathogenic bacteria and infectious episodes are common; thus, corticosteroids should be carefully used.

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