Abstract
Severity of dyspnea in COPD patients with comparable FEV1 is highly variable.
Aim: To compare clinical and functional parameters in COPD patients with varying dyspnea degree.
Methods: 88 COPD outpatients (GOLD II) aged 42-80 years were studied. COPD symptoms, spirometry and body plethysmography parameters, bronchial hyperresponsiveness (BHR) to methacholine challenge and concentration of serum biomarkers were analyzed. Depending on a dyspnea level all patients were divided two groups: 1-group (MRC 0-2) - 48 patients, 2-group (MRC 3) - 40 patients. Determinants of differences of degree of dyspnea were identified by means discriminant analysis.
Results: FEV1 values were similar in both groups (p = 0,58). Among clinical characteristics were defined a contribution to the difference of level dyspnea: COPD duration (F=22,8; p<0,001), exacerbations frequency (F=13,1; p<0,001) and age of patients (F=5,2; p=0,023). More severe dyspnea was associated also with residual volume – RV (F=8,0; p=0,006) and BHR (F=11,7; p<0,001). The use of these variables resulted in correct classification rates of 92% in general.
Patients of the 2-nd group (MRC 3) were older (p = 0,042) and their COPD duration was 2,2 times longer (p<0,001) compared with patients of the 1-st group. COPD exacerbations were more frequent in patients with severe dyspnea: 2,1 vs 1,2 per year (p<0,001). The post bronchodilator RV in the 2-nd group on average was on 14% higher than in the 1-st group (p<0,001). In severe dyspnea BHR was present in 95% of patients compared with 52% of cases in the 1-st group (p<0,001).
Conclusion: Significant dyspnea-related differences in COPD II patients is based mainly on COPD duration, exacerbations frequency, BHR, RV and age of patients.
- © 2013 ERS