Validity of multidimensional body mass index [B], airflow obstruction [O], dyspnea [D] and exercise capacity [E], BODE index as predictor of hospitalization for COPD

ABSTRACT

Patients with COPD have systemic manifestations that are not reflected by the FEV[1]. These systemic manifestations often correlate with increased risk of mortality and may be considered surrogates of disease severity. We hypothesized that the BODE [body mass index, airflow obstruction, dyspnea, and exercise capacity] index would better predict hospitalization for COPD than FEV1 alone. The purpose of this study was to test in a cohort of patients with COPD, how well a multidimensional grading system that assessed the respiratory and systemic expressions of COPD would better categorize and predict outcome in these patients. A total of 150 patients with COPD [ages 45-83 yr; 89% male] recruited from the outpatient clinic of Suez Canal University Hospital were enrolled in 30 months, prospective study and followed-up for a mean period of 12 months from January 2004-June 2006. The BODE index was calculated for each patient using variables obtained within 4 weeks of enrollment. The main outcome measure was the number of hospital admissions for COPD during follow-up. The following variables were assessed for each patient Age, sex, pack years of smoking, FVC%, FEV[1]%, the best of two 6 minute walk tests done 30 minutes apart, degree of dyspnea, body mass index [BMI]. We evaluated the relationship between FEV[1]%, the level of dyspnea, BMI, the best of two 6 minute walk tests done 30 minutes apart and BODE scores with the number of hospital admissions. After 30 months, 126 patients were available for the follow-up examination [follow-up rate, 84%]. During the follow-up period, 85 [67%] of patients required at least one hospital admission and 6 [4.8%] died. In multivariate analysis a significant effect of BODE score on the number of hospital admissions was found [95% confidence interval [CI], 0.36 to 0.61; p<0.000]. In comparison, there was a significant but smaller effect of the pack years of smoking, BMI and BMI score on the number of hospital admissions [[95% confidence interval [CI], 0. 03 to 0.05; p<0.000], [95% CI, -0.32 to -0.09; p<0.01] and [95% CI, -1.6 to -0.12; p<0.05] respectively]. FEV[1]%, the level of dyspnea, and 6 minute walk test were significant predictors of hospitalization in univariate analysis [p<0.000] but were excluded in multivariate analysis. The BODE staging system, which includes in addition to FEV[1] other physiologic and clinical variables, is a better predictor of hospital admissions than FEV[1] in COPD