Cluster Analysis on Longitudinal Data of Patients with Adult-Onset Asthma

J Allergy Clin Immunol Pract. Jul-Aug 2017;5(4):967-978.e3. doi: 10.1016/j.jaip.2017.01.027. Epub 2017 Apr 25.

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 FEV1 reversibility 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).

Keywords: Adult-onset; Asthma; Cluster analysis; Early-onset; Follow-up; Late-onset; Longitudinal; Obesity; Phenotypes; Smoking.

MeSH terms

  • Adolescent
  • Adrenal Cortex Hormones / therapeutic use
  • Adult
  • Age of Onset
  • Aged
  • Anti-Asthmatic Agents / therapeutic use
  • Asthma / diagnosis*
  • Asthma / drug therapy
  • Asthma / epidemiology
  • Cluster Analysis
  • Comorbidity
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Mental Disorders / epidemiology
  • Middle Aged
  • Obesity / epidemiology
  • Phenotype
  • Smoking / epidemiology
  • Young Adult

Substances

  • Adrenal Cortex Hormones
  • Anti-Asthmatic Agents

Associated data

  • ClinicalTrials.gov/NCT02733016