Validation of the modified BODE index using the activity domain of St George’s Respiratory Questionnaire

Objective The traditional BODE (Body-mass Index, Obstruction, Dyspnoea and Exercise) index can be challenging in routine practice. This study introduced the modified BODE (mBODE) index that replaces the exercise component with the activity domain of the St. George’s Respiratory Questionnaire (SGRQ). Our study aimed to evaluate its relationship with baseline clinical characteristics and its predictive performance for exacerbations and mortality compared to the original index. Methods Data were extracted from the Korean COPD Subgroup Study cohort. The activity domain of the SGRQ was divided into quartiles, replacing the exercise component of the BODE index to define the mBODE index. Clinical outcomes were compared between quartiles of the BODE and mBODE indices. We analysed the associations of both scores with 1-year exacerbations and all-cause mortality. Results This study enrolled 1765 individuals, and both scores were associated with moderate-to-severe and severe exacerbations. In the analysis of future exacerbation frequency, the Akaike information criterion (AIC) and log-likelihood values indicated that the mBODE index had better predictive performance than the BODE index in both models. In the analysis of the presence of future exacerbation, the AIC showed that the mBODE index had superior predictive performance compared to the BODE index. Furthermore, both indices predicted all-cause mortality in individuals with COPD (BODE: adjusted hazard ratio (aHR=2.53, p<0.001; mBODE: aHR=2.00, p<0.01). Conclusions The mBODE index reflected the clinical characteristics and showed association with exacerbations and mortality comparable to those of the traditional BODE index.