Both the CODEX (Comorbidity, Obstructive Dyspnea, Exacerbations) and mCODEX (modified CODEX) indices are good predictors of short-, medium-, and long-term mortality in patients with chronic obstructive pulmonary disease (COPD), according to study results published in the Journal of Chronic Obstructive Pulmonary Disease.

Pooled data from 26 cohort studies and the COPD Cohorts Collaborative International Assessment (3CIA) consortium database were used to calculate the CODEX and mCODEX indices for each participant. The CODEX index is composed of the combination of forced expiratory volume in 1 second percent predicted (FEV1%), dyspnea, and number of severe COPD exacerbations in the previous year, stratified according to the BODE (Body mass index, Obstructive, Dyspnea, Exercise) and BODEX (Body mass index, Obstructive, Dyspnea, Exacerbations) thresholds. mCODEX replaces the original CODEX thresholds for FEV1% and dyspnea (modified scale of the Medical Research Council) with the previously suggested cutoffs based on survival prediction analysis in 3CIA. Univariate Cox proportional hazard models were used to study the crude effect of the CODEX and mCODEX categories on survival.

Of the 3142 patients initially included in the study, 363 were excluded due to a lack of individual data to calculate CODEX index and 24 were excluded due to lack of follow-up. A total of 1175 (35.4%) patients were included after a hospitalization for exacerbation of COPD, while 2146 (64.6%) were selected in ambulatory settings. The overall observed mortality ranged from 6.3% at 1 year to 20% at 3 years and 58% at 10 years. The area under the curve for CODEX and mortality ranged from 0.72 at 3 months to 0.76 at 10 years. The mCODEX performed slightly better than CODEX, although without statistically significant differences, in the short (3 months) and medium term (1 year).

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“Our study confirms the utility of the CODEX index to predict mortality in a large set of COPD patients,” the researchers wrote. “Its reliability was demonstrated across diverse COPD populations, in all subgroups analyzed and in different periods of follow-up.”

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Almagro P, Martínez-Camblor P, Miravitlles M, et al; for the 3CIA Collaboration. External validation and recalculation of the CODEX Index in COPD patients. A 3CIAplus Cohort Study [published March 14, 2019]. COPD. doi:10.1080/15412555.2018.1484440