The CODEX index was developed and validated in patients hospitalized for
COPD exacerbation to predict the risk of death and readmission within one year
after discharge. Our study aimed to validate the CODEX index in a large
external population of COPD patients with variable durations of follow-up.
Additionally, we aimed to recalculate the thresholds of the CODEX index using
the cut-offs of variables previously suggested in the 3CIA study (mCODEX).
Individual data on 2,755 patients included in the COPD Cohorts Collaborative
International Assessment Plus (3CIA+) were explored. A further two cohorts
(ESMI AND EGARPOC-2) were added. To validate the CODEX index, the
relationship between mortality and the CODEX index was assessed using
cumulative/dynamic ROC curves at different follow-up periods, ranging from 3
months up to 10 years. Calibration was performed using univariate and
multivariate Cox proportional hazard models and Hosmer-Lemeshow test.
A total of 3,321 (87.8% males) patients were included with a mean ± SD age of
66.9±10.5 years, and a median follow-up of 1,064 days (IQR 25%-75% 426-
1643), totalling 11,190 person-years. The CODEX index was statistically
associated with mortality in the short- (≤3 months), medium- (≤1 year) and longterm (10 years), with an area under the curve of 0.72, 0.70 and 0.76
respectively. The mCODEX index performed better in the medium-term (<1
year) than the original CODEX, and similarly in the long-term.
In conclusion, CODEX and mCODEX index are good predictors of mortality in
patients with COPD, regardless of disease severity or duration of follow-up.
- CODEX index