Clinical efficacy of bronchodilators in equine asthma: Looking for minimal important difference

Summary Background Airway obstruction is the main trait of severe equine asthma that affects respiratory function and elicits detrimental effects on clinical presentation. Only few and underpowered clinical studies have investigated the impact of improvement in lung function induced by bronchodilators on the clinical signs of asthma‐affected horses. Objectives To identify the minimal important difference (MID) in lung function elicited by bronchodilator leading to a meaningful improvement in clinical signs. Study design Pairwise meta‐analysis and meta‐regression analysis. Methods Literature searches were performed for studies that investigated the effect of bronchodilator therapy on lung function and clinical condition of asthmatic horses. The relationship between the change in lung function variables and clinical score was analysed via random‐effect meta‐regression. One‐point change of the Improved clinically Detectable Equine Asthma Scoring System (IDEASS) score was used to identify the MID. Results A significant (P