title: Frequent exacerbations of chronic obstructive pulmonary disease--a distinct phenotype?
authors.forename: Donald P
authors.initials: DP
authors.lastname: Tashkin
mesh_terms: D004198:Disease Susceptibility; D006801:Humans; D010641:Phenotype; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012008:Recurrence; D012720:Severity of Illness Index