Validation of the i-BODE index as a predictor of hospitalization and mortality in patients with COPD participating in pulmonary rehabilitation

Abstract

Abstract The aim of this study was to examine the value of the i-BODE index to predict hospital admission and to confirm its usefulness to predict mortality in a Danish population. The incremental shuttle walking test (ISWT) is widely used in the UK and Europe and previous work has examined the replacement of the 6MWT with the ISWT within the BODE index for predicting the prognosis of COPD (i-BODE). The 674 patients included in the analysis participated in a 7-week pulmonary rehabilitation program from 2002 to 2011. The National Health Services Central Register ascertained vital status and provided information on all hospital admissions. The mean follow-up period was 66 months (range 11-118 months). Cox proportional hazards model was used to identify factors that significantly predicted mortality and time to first hospital admission. The i-BODE index as well as body mass index, MRC dyspnea grade, and exercise capacity (ISWT) were significantly associated with all-cause mortality. The adjusted hazard ratio for death per one point increase in the i-BODE score was 1.28 (95% confidence interval 1.20 to 1.37). The i-BODE index was also a significant predictor of hospitalization, both for all causes and COPD exacerbation. Patients in the highest i-BODE quartile had a median time to first hospitalization of 17 months compared to 51 months for patients in the lowest quartile. The i-BODE index is a significant predictor of hospital admission and thus health care utilization, and also mortality.

Keywords: BODE Index; Incremental Shuttle Walking Test; exercise test; survival.