Current Evidence on the Usefulness of Potential Therapies in the Prevention of COPD Exacerbations: Beyond the Use of Bronchodilator Therapy and Inhaled Corticosteroids Juan Marco Figueira-Gonçalves; Francisco Javier Callejas-González; Rafael Golpe; Luis Máiz-Carro; Marta Marín-Oto; Javier de Miguel-Díez; Guillermo Samuel Loscertales-Vacas; José María Tordera-Mora; Álvaro Hurtado-Fuentes;