Asthma is a heterogeneous disease where
patient severity can be classified according to various models based on
numerous variables. Large collections of well-phenotyped subjects are needed to
find distinct clusters of patients for personalized medicine and future genetic
studies.
Accurate description of asthma phenotypes is an ongoing challenge.
Cluster analysis aggregating phenotypes without a priori assumptions has become an optimal choice to define asthma.
And cluster analysis can offer clinicians and researchers a better insight on
the multiple phenotypes present in asthma patients for targeted therapies and
future genetic studies in more homogenous subgroups of patients.
The objective of this study was to describe
the collection of the Quebec City Case-Control Asthma Cohort and to identify
homogeneous subgroups of asthma patients based on clinical characteristics.
This cohort was part of an ongoing project
initiated in 2007 to elucidate the genetic basis of asthma. All subjects were
randomly recruited at the same site following advertisements. Subjects were
unrelated French Canadian white adults 18 years of age or older. Each
participant underwent a spirometry, methacholine challenge, and allergy
skin-prick tests. Blood was collected for DNA, cell counts and total serum IgE
measurements. And 982 subjects had been recruited and classified as cases (n = 566)
or controls (n = 416). The authors also performed factor and cluster
analyses on collected phenotypes from this set to identify subgroups of
phenotypically similar asthmatic patients.
The results
demonstrated that factor analysis with 13 variables led to the
selection of five factors: lung function, numbers of allergens, blood
eosinophil percentage, smoking status and age. K-means cluster analysis on the
reduced dataset produced four significantly different groups with the following
characteristics: smoking history, low atopy and low lung function, high atopy,
and young non-smoking with average atopy.
In conclusion,
the Quebec City Case-Control Asthma Cohort is a new resource for
local and collaborative clinical and genetic research on asthma. This new
collection reveals distinct multivariate phenotypes of adult asthma that are
likely to be important for future genetic studies and targeted therapies.
Article
by Émilie Lavoie-Charland, et al, from Canada.
Full
access: http://mrw.so/2OT4Zs
Image
by Hector Aiza Ramirez, from Flickr-cc.
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