A longitudinal study of serial BODE indices in predicting mortality and readmissions for COPD.

INTRODUCTION: BODE index comprises Body mass index, Obstruction of the airway [FEV(1)], Dyspnoea score [modified Medical Research Council questionnaire] and Exercise capacity [6 min walk test]. This study assessed the role of serial changes in BODE index in predicting mortality and readmissions of COPD patients.

METHODS: A prospective cohort study involving 243(208 males) COPD patients hospitalized for acute exacerbations of COPD [AECOPD]. BODE index was assessed at 6 weeks(baseline), 6, 12, 18 and 24 months post hospital discharge. Mortality and readmissions in the subsequent 3 years were recorded. All the patients were managed by usual care without additional intervention.

RESULTS: The mean (SD) age and FEV(1)% predicted were 74.2(7.8) yrs and 51.7(21.6)% respectively. Over the 3 years, 25.1% died whereas 76.5% had at least 1 readmission for AECOPD. Baseline BODE index was predictive of both the survival and readmissions to hospital for AECOPD by Cox regression analysis (p < 0.001 for both survival and readmissions). Over 24 months, 71(40.1%), 94(53.1%), 12(6.8%) patients had increased (>1 point), no change, and decreased in BODE (>1 point) index respectively. Serial changes in BODE index at 6 month was marginally associated with mortality, but not at 12-, 18- and 24-month. The 6-, 12- and 24-month BODE indices were predictive of the readmissions for AECOPD when compared to baseline.

CONCLUSION: Baseline BODE index could predict both survival and readmissions for AECOPD, whereas serial BODE indices were not predictive of survival at 3 years. Single rather than serial measurements of BODE index is sufficient for prediction of survival and readmissions for patients treated with usual care.