Stable State Proadrenomedullin Level in COPD Patients: A Validation Study

Abstract

ABSTRACTIn patients with stable COPD, proadrenomedullin (MR-proADM) has been shown to be a good predictor for mortality. This study aims to provide an external validation of earlier observed cut-off values used by Zuur-Telgen et al. and Stolz.et al. in COPD patients in stable state and at hospitalization for an acute exacerbation of COPD (AECOPD). From the COMIC cohort study we included 545 COPD patients with a blood sample obtained in stable state (n = 490) and/or at hospitalization for an AECOPD (n = 101). Time to death was compared between patients with MR-proADM cut-off scores 0.71 and 0.75 nmol/L for stable state or 0.79 and 0.84 nmol/l for AECOPD. The predictive value of MR-proADM for survival was represented by the C statistic. Risk ratios were corrected for sex, age, BMI, presence of heart failure, and GOLD stage. Patients above the cut-off of 0.75 nmol/l had a 2-fold higher risk of dying than patient below this cut-off (95% CI: 1.20–3.41). The cut-off of 0.71 nmol/l showed only a borderline significantly higher risk of 1.67 (95% CI: 0.98–2.85). The corrected odds ratios for one-year mortality were 3.15 (95% CI 1.15–8.64) and 3.70 (95% CI 1.18–11.6) in patients with MR-proADM levels above versus below the cut-off of respectively 0.75 and 0.71 nmol/l measured in stable state. MR-proADM levels in samples at hospitalization for an AECOPD were not predictive for mortality in this validation cohort. MR-proADM in stable state is a powerful predictor for mortality.