Type 2-High Severe Asthma with and without Bronchiectasis: A Prospective Observational Multicentre Study

Abstract

Introduction: Type 2-high severe asthma (T2-SA) is often associated with several comorbidities. To this extent, the coexistence of T2-SA and bronchiectasis (BE) is considered an emerging phenotype.

Methods: We performed a prospective observational multicentre study, including T2-SA patients. Chest HRCT confirmed the presence of BE. Data on exacerbations, pulmonary function, Asthma Control Test (ACT), chronic mucus hypersecretion (CMH), chronic rhinosinusitis (CRS), oral corticosteroid (OCS) dosage, eosinophils in peripheral blood and FeNO were recorded. The Bhalla score was used for radiological assessment of T2-SA+BE patients and the Bronchiectasis Severity Index (BSI) was calculated.

Results: A total of 113 patients (mean age 55 ± 11 years, 59.3% female) were enrolled. Co-presence of BE was confirmed in 50/113 (44.2%) patients who identified the T2-SA+BE group. CRS and CRSwNP were more prevalent in T2-SA+BE vs T2-SA [respectively, 42/50 (84%) vs 37/63 (58.7%), p = 0.004 and 27/50 (54%) vs 27/63 (42.9%), p = 0.0165]. Furthermore, T2-SA+BE patients reported more CMH compared to T2-SA [29/50 (58%) vs 15/63 (23.8%), p = 0.0004], were more frequently on chronic OCSs intake [28/50 (56%) vs 22/63 (34.9%), p = 0.0357] and experienced more exacerbations/year [10 (4-12) vs 6 (4-12), p = 0.0487]. In a multivariate logistic regression model, the presence of CRS, CMH and daily OCS intake were associated with BE presence with a 78% (95% CI: 69-88) accuracy. Median Bhalla score was 18.3 (16-20) (Mild radiological severity). Median BSI was 6 (4-8) and only 6/50 (12%) had a BSI score ≥9. Significant inverse linear relationship between BSI and ACT (r = -0.6095, p < 0.0001), FEV₁% (r = -0.3297, p = 0.0353) and FEV₁ mL (r = -0.4339, p = 0.0046) were found.

Conclusion: Type 2 inflammation could have a causative role in BE development. Chest HRCT is mandatory when a diagnosis of T2-SA is made, especially in presence of CRS, CMH and chronic OCS intake. Early BE detection may be crucial to improve T2-SA patients' outcomes.

Keywords: bronchiectasis; chest-CT scan; phenotype; severe asthma; type 2 inflammation.

Figure 1

Study flow chart.

Figure 2

Differences between Type-2 High Severe Asthma patients with and without Bronchiectasis with regard to chronic rhinosinusitis (A), chronic rhinosinusitis with nasal polyps (B), chronic sputum production (C), chronic oral corticosteroids intake (D) and asthma exacerbations in the previous year (E). Receiver operating characteristics (ROC) of the optimal regression model of variables (presence of chronic rhinosinusitis, chronic mucus hypersecretion and daily OCS intake) strongly associated with comorbid BE in T2-SA (F).

Figure 3

Bronchiectasis lobes involvement (A) and distribution pattern (B).

Figure 4

Distribution of patients in relation to Bhalla score items. Data as presented as percentage (%). 1. Severity of bronchiectasis: 0 = None; 1 = luminal diameter slightly larger than the adjacent vessel; 2 = bronchial diameter between 2 and 3 times the diameter of the adjacent vessel; 3 = bronchus is more than 3 times the diameter of the adjacent vessel. 2. Peribronchial thickening: 0 = None; 1 = wall thickness is similar to that of the surrounding vessel; 2 = wall thickness greater, but less than twice, the diameter of the adjacent vessel; 3 = more than twice the thickness of the adjacent vessel. 3. Extent of bronchiectasis: 0 = None; 1 = 1–5 segments; 2 = 6–9; 3 = >9. 4. Mucus plugs: 0 = None; 1 = 1–5 segments; 2 = 6–9; 3 = >9. 5. Sacculation/abscesses: 0 = None; 1 = 1–5 segments; 2 = 6–9; 3 = >9. 6. Generations of bronchial division involved: 0 = None; 1 = >4^a generations; 2 = >5^a; 3 = >6^a. 7. Bullae: 0 = None; 1 = unilateral; 2 = bilateral; 3 = >4. 8. Emphysema: 0 = None; 1 = 1–5 segments; 2 = >5. 9. Collapse/consolidation: 0 = None; 1 = subsegmental; 2 = segmental/lobar.

Figure 5

Correlations between BSI, ACT (A), FEV₁% (B) and FEV₁ mL (C).