TY - JOUR
T1 - Classification of hypersensitivity pneumonitis
T2 - A hypothesis
AU - Lacasse, Yves
AU - Selman, Moises
AU - Costabel, Ulrich
AU - Dalphin, Jean Charles
AU - Morell, Ferran
AU - Erkinjuntti-Pekkanen, Riitta
AU - Mueller, Nestor L.
AU - Colby, Thomas V.
AU - Schuyler, Mark
AU - Jomphe, Valérie
AU - Cormier, Yvon
PY - 2009/5
Y1 - 2009/5
N2 - Background: Regardless of the causative antigen, hypersensitivity pneumonitis (HP) is usually classified as 'acute', 'subacute' or 'chronic'. Considerable confusion still surrounds this classification because there are no widely accepted criteria to distinguish the various stages. The objective of this study wasto determine whether the current classification of HP truly reflects categories of patients with distinct clinical features. Methods: Data obtained from a large prospective multicenter cohort study (the HP Study) were used to divide a cohort of patients with HP into a limited number of categories (clusters) with maximally differing clinical patterns, without prejudgment. The results of this cluster analysis were compared with the current classification of HP (acute, subacute or chronic). Results: 168 patients were included in the analysis. A 2-cluster solution best fitted the data. Patients in cluster 1 (41 patients) had more recurrent systemic symptoms (chills and body aches) and normal chest radiographs than those in cluster 2 (127 patients) who showed significantly more clubbing, hypoxemia, restrictive patterns on pulmonary function tests and fibrosis on high-resolution computed tomography (HRCT). All p values were <0.0001, using Fisher's exact test. Nodular opacities were seen on HRCT as often in cluster 1 as in cluster 2. There was considerable disagreement between the current classification of HP and the results of our analysis. Conclusion: The current classification of acute, subacute and chronic HP is not supported by our analysis. Subacute HP is particularly difficult to define.
AB - Background: Regardless of the causative antigen, hypersensitivity pneumonitis (HP) is usually classified as 'acute', 'subacute' or 'chronic'. Considerable confusion still surrounds this classification because there are no widely accepted criteria to distinguish the various stages. The objective of this study wasto determine whether the current classification of HP truly reflects categories of patients with distinct clinical features. Methods: Data obtained from a large prospective multicenter cohort study (the HP Study) were used to divide a cohort of patients with HP into a limited number of categories (clusters) with maximally differing clinical patterns, without prejudgment. The results of this cluster analysis were compared with the current classification of HP (acute, subacute or chronic). Results: 168 patients were included in the analysis. A 2-cluster solution best fitted the data. Patients in cluster 1 (41 patients) had more recurrent systemic symptoms (chills and body aches) and normal chest radiographs than those in cluster 2 (127 patients) who showed significantly more clubbing, hypoxemia, restrictive patterns on pulmonary function tests and fibrosis on high-resolution computed tomography (HRCT). All p values were <0.0001, using Fisher's exact test. Nodular opacities were seen on HRCT as often in cluster 1 as in cluster 2. There was considerable disagreement between the current classification of HP and the results of our analysis. Conclusion: The current classification of acute, subacute and chronic HP is not supported by our analysis. Subacute HP is particularly difficult to define.
KW - Cluster analysis
KW - Extrinsic allergic alveolitis
KW - Hypersensitivity
KW - Pneumonitis, classification
UR - http://www.scopus.com/inward/record.url?scp=58149155992&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=58149155992&partnerID=8YFLogxK
U2 - 10.1159/000189200
DO - 10.1159/000189200
M3 - Article
C2 - 19127074
AN - SCOPUS:58149155992
SN - 1018-2438
VL - 149
SP - 161
EP - 166
JO - International archives of allergy and immunology
JF - International archives of allergy and immunology
IS - 2
ER -