Association between Frailty Index and BODE index with lung function and mortality in COPD

Abstract

<b>Background:</b> Frailty is a clinical condition characterized by high vulnerability to internal and external stressors and represents a strong predictor of adverse outcomes. Only one study has investigated frailty in COPD, however participants did not perform a throughout pulmonary assessment and no comparison was performed with a disease specific prognostic index, like the BODE index (BI). <b>Aim:</b> to test the correlation between indexes of lung function with a 36-item frailty index (FI) and BI and to verify the association between FI and mortality. <b>Methods:</b> Stable COPD patients were consecutively enrolled in the outpatient clinic of Campus Bio-Medico Teaching Hospital and followed-up for 4 years. At baseline, participants performed a geriatric multidimensional assessment, spirometry, arterial gas analysis, 6-minute walking test and bioimpedance analysis. BI and FI, ranging from 0 (the best) to 1 (the worse) and not including respiratory parameters, were calculated. Survival was ascertained by phone calls. Spearman’s ρ was used to assess correlation between lung volume and expiratory flows with FI and BI. Patient survival was assessed using Kaplan Meier curves. <b>Results:</b> 150 COPD patients, mean age 73 years, median FI 0.15 (IQR:0.11-0.19), were enrolled and followed up for a median of 39 months. FI was higher in frequent exacerbators (≥2/year) [mean: 0.18 vs 0.14, p:0.01] and dyspnoeic patients (mMRC≥2) [mean 0.21 vs 0.14, p:&lt;0.01] and correlated with lung volume and expiratory flows, even slightly worse than BODE. No difference in survival was observed in patients with FI above the median (p:0.14). <b>Conclusion:</b> FI associates with lung function in COPD patients, but does not associate with mortality.