Performance of the BODE index in patients with α₁-antitrypsin deficiency-related COPD

Abstract

The BODE (body mass index, airflow obstruction, dyspnoea and exercise capacity) index is used to decide on referral and transplantation of patients with chronic obstructive pulmonary disease (COPD). The BODE index has not been validated in patients with α1-antitrypsin deficiency, who account for 15% of COPD patients undergoing lung transplantation. We sought to validate the BODE index in α1-antitrypsin deficiency-related COPD. We assessed the prognostic value of the BODE index in 191 patients followed from 2006 to 2012 in a French prospective cohort of patients with α1-antitrypsin deficiency. 20 patients died during follow-up and 22 underwent lung transplantation. Survival (95% CI) was 93.0% (91.7-94.3%) at 3 years and 76.0% (72.9-79.1%) at 5 years. The 3-year survival was 97.4% (96.6-98.2%), 98.0% (96.7-99.3%), 87.7% (84.5-90.9%) and 75.3% (66.0-84.6%) for patients with BODE index 0-2, 3-4, 5-6 and 7-10, respectively. Survival discrimination of the BODE index was better than with both forced expiratory volume in 1 s and Global Initiative for Chronic Obstructive Lung Disease classification. Regarding calibration, expected survival by BODE index was noticeably lower than observed survival. The BODE index showed very good survival discrimination in patients with α1-antitrypsin deficiency-related COPD. Larger studies are needed to support its use to drive patient referral for lung transplantation.