Body mass index, airflow obstruction and dyspnea and body mass index, airflow obstruction, dyspnea scores, age and pack years-predictive properties of new multidimensional prognostic indices of chronic obstructive pulmonary disease in primary care

BACKGROUND The assessment of the severity of chronic obstructive pulmonary disease (COPD) should involve a multidimensional approach that is now clearly shown to be better than using spirometric impairment alone. The aim of this study is to validate and compare novel tools without an exercise test and to extend prognostic value to patients with less severe impairment of Forced expiratory volume 1 s. METHODS A prospective, observational, primary care cohort study identified 458 eligible patients recruited from the primary care clinics in the northeast of England in 1999-2002. A new prognostic indicator - body mass index, airflow obstruction and dyspnea (BOD) together with the conventional prognostic indices age, dyspnea and airflow obstruction (ADO), global initiative for chronic obstructive lung disease (GOLD) and new GOLD matrix were studied. We also sought to improve prognostication of BOD by adding age (A) and smoking history as pack years (S) to validate BODS (BOD with smoking history) and BODAS (BOD with smoking history and age) as prognostic tools and the predictive power of each was analyzed. RESULTS The survival of the 458 patients was assessed after a median of 10 years when the mortality was found to be 33.6%. The novel indices BOD, BODS, and BODAS were significantly predictive for all-cause mortality in our cohort. Furthermore with ROC analysis the C statistics for BOD, BODS, and BODAS were 0.62, 0.66, and 0.72, respectively (P < 0.001 for each), whereas ADO and GOLD stages had a C statistic of 0.70 (P < 0.001) and 0.56 (P < 0.02), respectively. GOLD Matrix was not significant in this cohort. CONCLUSION BOD, BODS, and BODAS scores are validated predictors of all-cause mortality in a primary care cohort with COPD.