Multinational cohort study of mortality in patients with asthma and severe asthma by Engelkes, M, de Ridder, M, Svensson, E, Berencsi, E, Prieto-Alhambra, D, Lapi, F, Giaquinto, C, Picelli, G, Boudiaf, N, Albers, F, Cockle, S, Bradford, E, Suruki, R, Brusselle, GG, Rijnbeek, P, Sturkenboom, M, Verhamme, K