HLA B27 and respiratory involvement in axial spondylarthropathies. A retrospective study in 107 male patients.
OBJECTIVE: To conduct a retrospective study of respiratory involvement in axial spondylarthropathies according to HLA B27 status. METHOD: Schöber's index, chest expansion and lung function parameters were measured in 107 male inpatients with spondylarthropathies, including 78 with and 29 without the HLA B27 antigen (groups I and II, respectively). Active or severe spondylarthropathy was defined based on widely used clinical and laboratory test parameters. RESULTS: The two groups were similar regarding age, body mass index, disease duration, proportion of smokers and proportion of patients requiring nonsteroidal antiinflammatory drug therapy. Overall, 30 patients had pure active disease, 11 had pure severe disease, 26 had active severe disease and 40 had nonactive nonsevere disease. Group I patients were significantly more likely to have active severe disease than group II patients, whereas the opposite was true for nonactive nonsevere disease. Mean erythrocyte sedimentation rate was higher in group I (22.6 +/- 21.6) than in group II (13.3 +/- 12.5) (P = 0.039). Group I patients had lower values for chest expansion (5.4 +/- 2.2 cm versus 6.37 +/- 1.9 cm; P = 0.045), vital capacity (91.9% +/- 13.9% versus 99.5% +/- 17.6%; P = 0.021), and total capacity (91.8 +/- 12.3 versus 98.1 +/- 13.9; P = 0.025). A restrictive defect was found in 12 group I patients versus one group II patient (nonsignificant difference). All patients with restrictive defects had active and/or severe disease. Two-way analysis of variance and Fisher's PSLD post-test suggested that lung function was influenced by disease severity but not by disease activity. CONCLUSION: Lung function impairment may be more common and more severe in HLA B27-positive than in HLA B27-negative spondylarthropathy patients. This difference may be entirely ascribable to increased disease severity in HLA B27-positive patients.