[Characteristics of type 2 inflammation in nocturnal asthma and evaluation of the effectiveness of inhaled corticosteroids combination therapy].

Objective: To investigate the characteristics of type 2 inflammation in patients with nocturnal asthma, and analyze the improvement of asthma symptoms after the use of inhaled corticosteroids (ICS) combined with different long-acting bronchodilators. Methods: Data of 231 asthma patients who first visited the Respiratory and Critical Care Medical Clinic of Nanfang Hospital of Southern Medical University from January 2020 to June 2023 and had positive bronchodilator tests (BDT), were retrospectively analyzed. These patients were divided into nocturnal asthma group and non-nocturnal asthma group based on the presence or absence of nocturnal symptoms. According to fractional exhaled nitric oxide (FeNO) levels, patients were divided into type 2 inflammatory group [FeNO≥20 ppb (×10^-12)] and non-type 2 inflammatory group (FeNO<20 ppb). Patients were further divided into ICS+long-actingβ2 agonist (LABA) group and ICS+LABA+long-acting anticholinergic agent (LAMA) group based on medication regimens. Patients were followed-up at the 3rd, 6th, and 12th months after enrollment to evaluate the patient's asthma control test (ACT) questionnaire, actual medication status and number of acute attacks. The clinical characteristics, treatment and prognosis of different groups were compared. Results: A total of 231 asthma patients were included, including 152 males and 79 females, with a age[M (Q₁, Q₃)] of 52 (42, 60) years. There were 144 cases (62.3%) in the nocturnal asthma group and 87 cases (37.7%) in the non-nocturnal asthma group. Among the 144 patients with nocturnal asthma, 133 patients completed FeNO testing, of which 95 were classified into the type 2 inflammation group and 38 to the non-type 2 inflammation group. The eosinophil (EOS) count and FeNO level in the nocturnal asthma group were both higher than those in the non-nocturnal asthma group [(0.45±0.40) ×10⁹/L vs (0.25±0.20)×10⁹/L, 38 (18, 82) vs 29 (15, 48) ppb, both P<0.05]. Baseline ACT score was lower in nocturnal asthma group than in non-nocturnal asthma group [16 (14, 18) vs 21 (19, 23) scores, P<0.001]. There was no significant difference in the forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and peak expiratory flow (PEF) in the two groups (both P>0.05). During the follow-up at the 3rd, 6th, and 12th months, the improvement values of ACT scores (ΔACT) in the nocturnal asthma group were higher than the non-nocturnal asthma group [5 (3, 7) vs 2 (1, 3), 7 (4, 9) vs 3 (1, 4) and 7 (6, 9) vs 3 (1, 5) scores, all P<0.05]. The EOS count [0.40 (0.29, 0.80)×10⁹/L vs 0.20 (0.12, 0.29)×10⁹/L] and percentage [5.10% (3.55%, 9.10%) vs 2.20% (1.65%, 3.85%)] of the type 2 inflammation group were both higher than the non-type 2 inflammation group (both P<0.05). In the nocturnal asthma group, there was no significant difference in ΔACT between ICS+LABA and ICS+LABA+LAMA groups (both P>0.05). Conclusions: Patients with nocturnal asthma have more pronounced type 2 inflammation and the symptoms are often not well controlled or even worse. After one year of combined therapy with ICS, significant improvements in asthma symptoms can be observed. But there is no significant difference in symptom improvement among different medication regimens in the nocturnal asthma group.