Oral corticosteroids for post-infectious cough in adults: study protocol for a double-blind randomized placebo-controlled trial in Swiss family practices (OSPIC trial)

BACKGROUND: Cough is a common reason for patients to visit general practices. So-called post-infectious cough is defined as lasting 3 to 8 weeks after an upper respiratory tract infection. It can be disabling in daily activities, with substantial impact on physical and psychosocial health, leading to impaired quality of life and increased health care costs. Recommendations for the management of post-infectious cough in primary care are scarce and incoherent. A systematic review and meta-analysis of randomized clinical trials (RCT) assessing patient-relevant benefits and potential harms of available treatments identified six eligible RCTs assessing different treatment regimens (i.e. inhaled fluticasone propionate, inhaled budesonide, salbutamol plus ipratropium-bromide, montelukast, nociception-opioid-1-receptor agonist, codeine, gelatine). No RCT found clear patient-relevant benefits and most had an unclear or high risk of bias. Post-infectious cough is thought to be mediated by inflammatory processes that are also present in exacerbations of asthma or chronic obstructive pulmonary diseases for which there is strong evidence that oral corticosteroids provide patient-relevant benefit without relevant harm. We therefore plan to conduct the first RCT evaluating the effectiveness of oral corticosteroids for post-infectious cough. METHODS: We are conducting a triple-blinded randomized-controlled and multicentred superiority trial in primary health care practices in Switzerland. We will include 204 adult patients who consult their general practitioner (GP) for a cough lasting 3 to 8 weeks following an upper respiratory tract infection. Participants will be randomly allocated to either the 5-day treatment with oral corticosteroids or placebo. The primary outcome is cough-related quality of life assessed by the Leicester Cough Questionnaire score 14 days after randomization. Secondary outcomes include cough-related quality of life at several time points, overall cessation of cough and adverse events. DISCUSSION: This RCT will provide evidence on whether oral corticosteroids are beneficial and safe in patients with post-infectious cough. Results can have a substantial impact on the well-being and management of these patients in Switzerland and beyond. An evidence-based treatment for this condition may reduce re-consultations with GPs and spending for antitussive drugs, thus possibly having an impact on health care spending. TRIAL REGISTRATION: ClinicalTrials.gov NCT04232449. Prospectively registered on 18 January 2020.