Oral prednisolone for acute lower respiratory tract infection in clinically unrecognised asthma: an exploratory analysis of the Oral Steroids for Acute Cough (OSAC) randomised controlled trial

BACKGROUND: Acute lower respiratory tract infection (ALRTI) is often treated in primary care with antibiotics. The recent Oral Steroids for Acute Cough (OSAC) randomised controlled trial (RCT) showed corticosteroids were not an effective alternative in adults without a diagnosis of asthma with ALRTI. AIM: To investigate if corticosteroids are beneficial for ALRTI in patients with unrecognised asthma. DESIGN & SETTING: An exploratory analysis was undertaken of the primary care OSAC trial. METHOD: A subgroup analysis was performed in patients who responded ‘yes’ to the following International Primary Care Airways Group (IPCAG) question: did you have wheeze and/or at least two of nocturnal cough or chest tightness or dyspnoea in the past year. Sensitivity analyses were carried out on those who answered ‘yes’ to wheeze and at least two of the nocturnal symptoms. The primary outcomes were as follows: duration of cough (0–28 days, minimum clinically important difference [MCID] of 3.79 days) and mean symptom severity score (range 0–6; MCID 1.66 units). RESULTS: In total, 40 (10%) patients were included in the main analysis: mean age 49 years (standard deviation [SD] = 17.9), 52% male. Median cough duration was 3 days in both prednisolone (interquartile range [IQR] = 2–6 days) and placebo (IQR = 1–6 days) groups (adjusted hazard ratio [HR] = 1.10; 95% confidence interval [CI] = 0.47 to 2.54; P = 0.83), equating to 0.24 days longer in the prednisolone group (95% CI = 1.23 days shorter to 2.88 days longer). Mean symptom severity difference was –0.14 (95% CI = –0.78 to 0.49; P=0.65) comparing prednisolone with placebo. Similar findings were found in the sensitivity analysis. CONCLUSION: No evidence was found to support the use of corticosteroids for ALRTI in patients with clinically unrecognised asthma. Clinicians should not use the IPCAG questions to target oral corticosteroid treatment in patients with ALRTI.