Oral corticosteroid dosing strategies for post-COVID-19 organising pneumonia: NORCOVID clinical trial.

BACKGROUND: Organising pneumonia is an interstitial lung disease linked to infections and other conditions. Cryptogenic organising pneumonia is a rarer, idiopathic form. Organising pneumonia has become one of the most frequent respiratory complications following severe acute respiratory syndrome coronavirus 2 pneumonia. Standard treatment involves the use of glucocorticoids. The objective of the study is to determine the optimal dosage of oral corticosteroids for the treatment of this disease. METHODS: Randomised, open-label, assessor-blinded, parallel-group, single-centre, noninferiority clinical trial with an active control group comparing two oral prednisone regimens. The control group received prednisone 0.75 mg·kg-1·day-1 for 4 weeks; 0.5 mg·kg-1·day-1 for 4 weeks; 20 mg·day-1 for 4 weeks; 10 mg·day-1 for 6 weeks; or 5 mg·day-1 for 6 weeks (total treatment duration 6 months) and the experimental group prednisone 0.5 mg·kg-1·day-1 for 3 weeks; 20 mg·day-1 for 3 weeks; 15 mg·day-1 for 2 weeks; 10 mg·day-1 for 2 weeks; and 5 mg·day-1 for 2 weeks (total treatment duration 3 months). Visits were carried out at baseline and at 3, 6 and 12 months, recording clinical history, physical examination, pulmonary function tests and chest computed tomography. The primary outcome was noninferiority with a margin of 10% in diffusing capacity of the lung for carbon monoxide (D LCO) at 6 months. RESULTS: 79 patients were randomised according to intention-to-treat group, 40 to the experimental group and 39 to the control group. Mean±sd baseline D LCO was 59.3±16.7% in the experimental group and 55.5±16.5% in the control group, with mean improvements at 6 months of 11.7% (95% CI 7.18-16.17%) and 12.8% (95% CI 8.57-17.11%) respectively. The difference between groups at 6 months was 1.23% (95% CI -5.13-7.59%), the experimental regimen being noninferior to the control group with the margin of 10%. Patients in the experimental group had fewer than half as many adverse effects as controls: nine (23%) versus 22 (56%) (p=0.0027). CONCLUSIONS: Treatment with oral corticosteroids lasting 3 months (initial dose of prednisone 0.5 mg·kg-1·day-1) may be recommended in patients with post-COVID organising pneumonia.