Abstract
Background
Clinical phenotypes of asthma are well predicted by latent class analysis (LCA) of wheezing patterns during the first 6 years of age (Depner et al., AJRCCM 2014;189:129-138). Unremitting wheeze (symptoms between episodes) emerged as a sensitive phenotype, whereas recurrent unremitting wheeze was highly specific.
Objective
To test whether clinical asthma phenotypes determined by age 6 can already be predicted from LCA at earlier time points.
Methods
LCA based on yearly questions about wheeze until the respective time point was performed at age 3, 4, 5, and 6 years in the PASTURE (Protection against Allergy–Study in Rural Environments) birth cohort (n=1133). Quality of prediction was compared by area under the curve (AUC).
Results
At any age, the four class solutions of LCA resulted in similar patterns, which followed the known trajectories of infrequent, transient, late-onset, and persistent wheeze. The figure illustrates receiver operating characteristics curves for unremitting (left panel) and recurrent unremitting wheeze (right panel) with respect to LCA in the respective years. Despite an improvement in prediction for later solutions, already at 4 years of age an LCA predicted sensitive and specific asthma phenotypes well with an AUC of 82% and 91%, respectively.
Conclusion
LCA might be a useful tool for the definition of asthma surrogate markers in epidemiologic studies in young children.
- © 2014 ERS