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

Summary 

Introduction

BODE index comprises Body mass index, Obstruction of the airway [FEV₁], 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(208males) 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 FEV₁% 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 (>1point), no change, and decreased in BODE (>1point) 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.

Keywords: COPD, Serial BODE index, Mortality, Readmissions

Abbreviations: 6-MWT, 6-min walk test, AECOPD, acute exacerbations of COPD, COPD, chronic obstructive pulmonary disease, FEV₁, forced expiratory volume in 1 s, FVC, forced vital capacity, ICS, inhaled steroid, LABA, long acting beta-agonist, mMRC, modified Medical Research Council