title: Cluster Analysis on Longitudinal Data of Patients with Adult-Onset Asthma.
abstract: BACKGROUND
  Previous cluster analyses on asthma are based on cross-sectional data.
  
  
  OBJECTIVE
  To identify phenotypes of adult-onset asthma by using data from baseline (diagnostic) and 12-year follow-up visits.
  
  
  METHODS
  The Seinäjoki Adult Asthma Study is a 12-year follow-up study of patients with new-onset adult asthma. K-means cluster analysis was performed by using variables from baseline and follow-up visits on 171 patients to identify phenotypes.
  
  
  RESULTS
  Five clusters were identified. Patients in cluster 1 (n = 38) were predominantly nonatopic males with moderate smoking history at baseline. At follow-up, 40% of these patients had developed persistent obstruction but the number of patients with uncontrolled asthma (5%) and rhinitis (10%) was the lowest. Cluster 2 (n = 19) was characterized by older men with heavy smoking history, poor lung function, and persistent obstruction at baseline. At follow-up, these patients were mostly uncontrolled (84%) despite daily use of inhaled corticosteroid (ICS) with add-on therapy. Cluster 3 (n = 50) consisted mostly of nonsmoking females with good lung function at diagnosis/follow-up and well-controlled/partially controlled asthma at follow-up. Cluster 4 (n = 25) had obese and symptomatic patients at baseline/follow-up. At follow-up, these patients had several comorbidities (40% psychiatric disease) and were treated daily with ICS and add-on therapy. Patients in cluster 5 (n = 39) were mostly atopic and had the earliest onset of asthma, the highest blood eosinophils, and FEV1reversibility at diagnosis. At follow-up, these patients used the lowest ICS dose but 56% were well controlled.
  
  
  CONCLUSIONS
  Results can be used to predict outcomes of patients with adult-onset asthma and to aid in development of personalized therapy (NCT02733016 at ClinicalTrials.gov).
authors.affiliation: Department of Respiratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland. Electronic address: pinja.ilmarinen@epshp.fi.
authors.forename: Pinja
authors.initials: P
authors.lastname: Ilmarinen
authors.affiliation: Department of Respiratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland.
authors.forename: Leena E
authors.initials: LE
authors.lastname: Tuomisto
authors.affiliation: Department of Laboratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland; University of Tampere, Tampere, Finland.
authors.forename: Onni
authors.initials: O
authors.lastname: Niemelä
authors.affiliation: Department of Respiratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Tommola
authors.affiliation: Department of Clinical Physiology, Seinäjoki Central Hospital, Seinäjoki, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Haanpää
authors.affiliation: Department of Respiratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland; Department of Respiratory Medicine, University of Tampere, Tampere, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Kankaanranta
mesh_terms: D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D017668:Age of Onset; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D016000:Cluster Analysis; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D010641:Phenotype; D012907:Smoking / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D018927:Anti-Asthmatic Agents
keywords: Adult-onset; Asthma; Cluster analysis; Early-onset; Follow-up; Late-onset; Longitudinal; Obesity; Phenotypes; Smoking