Clinical efficacy of inhaled corticosteroids in equine asthma: A meta-analysis and number needed to treat

Equine asthma, a prevalent chronic inflammatory condition affecting the equine population, significantly compromises the performance and quality of life in affected horses. Inhaled corticosteroids (ICS) are often the first-line pharmacological intervention due to their potent anti-inflammatory properties. This meta-analysis investigates the clinical efficacy of ICS in treating equine asthma, emphasizing the number needed to treat (NNT) and the likelihood of achieving a clinical response. A comprehensive literature search identified relevant studies comparing ICS with placebo (PCB) controlled treatments. Data were synthesized from four clinical trials involving 252 asthmatic horses. Results indicate an overall NNT of 3.2 (95 % CI 2.3-4.7), meaning that approximately three horses must be treated with ICS for one to achieve a significant clinical response. Additionally, the relative risk of achieving clinical improvement with ICS versus PCB was 1.73 (95 % CI 1.47-2.02), demonstrating a marked increase in therapeutic effectiveness. Subgroup analysis revealed an NNT of 3.0 for severe cases, underscoring the efficacy of ICS across different severity levels. Despite potential biases noted in some studies, sensitivity analyses confirmed the robustness of these findings. The GRADE assessment rated the quality of evidence as high. These results highlight the therapeutic value of ICS in managing equine asthma, providing evidence-based recommendations for their clinical use. Future research should explore long-term outcomes and potential synergistic effects of ICS combined with other treatments to enhance clinical efficacy in managing equine asthma.