Effects Of 6-minute Walk Test In Patients With COPD

AIM:This study was designed to evaluate the value of 6MWT in patients with chronic obstructive pulmonary disease(COPD).METHODS:1.Seventy patients diagnosed with COPD were enrolled from Department of Respiratory Medicine in the second affiliated hospital of Kunming Medical College from September 2007 to October 2008,including 61 males and 9 females,with a mean age of(70.39±0.99)years;and 30 patients with other diseases admitted in Department of Respiratory Medicine were taken as controls,including 22 males and 8 females,with a mean age of(68.07±2.82) years.2.All patients were tested with 6MWT,lung function,BMI,spO₂ change fraction and heart rate change fraction,beside that,COPD patients were tested MMRC dyspnea scale,lung function scale and 6MWD scale.The results were conducted for t test,Kruskal-Wallis related samples test,ROC curve analysis,linear correlation analysis and multiple stepwise regression analysis.Pearson correlation coefficient and coincidence rate were also calculated.RESULTS:1.Compared with control group,the spO₂ change fraction and heart rate change fraction were significantly higher and 6MWD was significantly shorter in the COPD patients(P < 0.05).2.ROC curve analysis showed that the spO₂ change fraction and heart rate change fraction had middling diagnosis value for COPD,the best diagnosis points were 3.26%and 7.70%,But 6MWD had low diagnosis value for COPD.3.1 Linear correlation analysis indicate that,FEV₁%pred,FEV₁,FVC had a positive relationship with 6MWD.Multiple stepwise regression analysis revealed that,FEV₁% pred(β=-0.555,P<0.05 ).FEV₁(β=0.547,P<0.05 ),spO₂ change fraction(β=-0.265, P<0.05 ) were the meaningful predictor of 6MWD.3.2Linear correlation analysis indicate that,FEV₁%pred,FVC,BMI had a negative relationship and heart rate change fraction had a positive relationship with spO₂ change fraction.Multiple stepwise regression analysis revealed that,BMI(β=-0.364, P<0.05),heart rate change(β=0.346,P<0.05),6MWD(β=-0.267,P<0.05 ) were the meaningful predictor of spO₂ change fraction.3.3 Linear correlation analysis indicate that,FVC,FEV₁/FVC,FEV₁%predhad a negative relationship and spO₂ change fraction had a positive relationship with heart rate change fraction.Multiple stepwise regression analysis revealed that,FVC (β=-0.489,P<0.05 ),FEV₁/FVC(β=-0.369,P<0.05 ),spO₂(c)(β=-0.267,P<0.05 ) were the meaningful predictor of heart rate change fraction.3.4 Linear correlation analysis indicate that,spO₂ change fraction had a negative relationship and FEV₁/FVC,FEV₁%pred had a positive relationship with BMI. Multiple stepwise regression analysis revealed that,spO₂(c)(β=-0.354,P<0.05 ),FEV₁/FVC(β=0.274,P<0.05) were the meaningful predictor of BMI.4.1Middle and serious patients with COPD had high coincidence rate between lung function scale and 6MWD scale.6MWD had a positive relationship with FEV₁%pred (R=0.261 p<0.05 ).4.2 Middle,serious and more serious patients with COPD had high coincidence rate between 6MWD scale and MMRC dyspnea scale.6MWD had a negative relationship with MMRC dyspnea scale(R=-0.610,p<0.05 ).CONCLUSION:1.spO₂ change fraction in 6MWT had some diagnosis value for COPD.2.6MWT had a relationship with lung function.6MWT was an effective method for detecting COPD patients' condition.3.BMI was an important factor in progress of COPD.4.6MWD scale and MMRC dyspnea scale were used to evaluate middle and serious patients with COPD.