Chest
Volume 145, Issue 5, May 2014, Pages 972-980
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Original Research
Short- and Medium-term Prognosis in Patients Hospitalized for COPD Exacerbation: The CODEX Index

https://doi.org/10.1378/chest.13-1328Get rights and content

Background

No valid tools exist for evaluating the prognosis in the short and medium term after hospital discharge of patients with COPD. Our hypothesis was that a new index based on the CODEX (comorbidity, obstruction, dyspnea, and previous severe exacerbations) index can accurately predict mortality, hospital readmission, and their combination for the period from 3 months to 1 year after discharge in patients hospitalized for COPD.

Methods

A multicenter study of patients hospitalized for COPD exacerbations was used to develop the CODEX index, and a different patient cohort was used for validation. Comorbidity was measured using the age-adjusted Charlson index, whereas dyspnea, obstruction, and severe exacerbations were calculated according to BODEX (BMI, airflow obstruction, dyspnea, and previous severe exacerbations) thresholds. Information about mortality and readmissions for COPD or other causes was collected at 3 and 12 months after hospital discharge.

Results

Two sets of 606 and 377 patients were included in the development and validation cohorts, respectively. The CODEX index was associated with mortality at 3 months (P < .0001; hazard ratio [HR], 1.5; 95% CI, 1.2-1.8) and 1 year (P < .0001; HR, 1.3; 95% CI, 1.2-1.5), hospital readmissions in the same periods, and their combination (all P < .0001). All CODEX C statistics were superior to those of the BODEX, DOSE (dyspnea, airflow obstruction, smoking status, and exacerbation frequency), and updated ADO (age, dyspnea, and airflow obstruction) indexes.

Conclusions

The CODEX index was a useful predictor of survival and readmission at both 3 months and 1 year after hospital discharge for a COPD exacerbation, with a prognostic capacity superior to other previously published indexes.

Section snippets

Materials and Methods

Data from the EPOC en los Servicios de Medicina Interna (ESMI) study were used for the development of the CODEX (comorbidity, obstruction, dyspnea, and previous severe exacerbations) index. The ESMI study is a longitudinal, observational, multicenter study conducted in 70 EDs and internal medicine services in Spain. Investigators included the first 10 consecutive patients seen for a severe COPD exacerbation during a 1-year period (October 2009-October 2010). Full methodology is available

Development Cohort

Overall, 679 patients were screened, and 606 were included in the initial ESMI study. Fifteen patients were excluded for having an incomplete minimum dataset, and in another 58 cases, spirometry was unable to be performed or did not fulfill the spirometric criteria for COPD (Fig 1). No differences existed between included and excluded patients with respect to age, sex, smoking history, or dyspnea measured by the mMRC scale (data not shown). Our study included patients hospitalized for

Discussion

Our study, performed in patients hospitalized for AECOPD, has three main findings. First, we demonstrated that a simple index can be useful in predicting survival in both the short and medium term after hospital discharge in these patients. Second, we reported the usefulness of this CODEX index in evaluating the risk of readmission, as well as the composite end point (readmission and/or mortality). Third, we had the opportunity to compare the prognostic validity with other previously validated

Conclusions

In conclusion, the CODEX index is a simple, valid tool for predicting survival and risk of COPD readmission or their combination in patients hospitalized for AECOPD during the year after hospital discharge, and it can be used to assess the severity of COPD in this population. Determining its usefulness in other populations requires further study.

Acknowledgments

Author contributions: Dr Almagro had full access to all the data in the study and takes responsibility for its integrity and the accuracy of the data analysis.

Dr Almagro: contributed to the study design, analysis and interpretation of the data, and writing of the manuscript.

Dr Soriano: contributed to the study design, analysis and interpretation of the data, and writing of the manuscript.

Dr Cabrera: contributed to the data collection and review of the manuscript.

Dr Boixeda: contributed to the

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    Dr Soriano is currently at FISIB-IdISPA Hospital Universitari Son Espases (Palma de Mallorca, Spain).

    *A complete list of study investigators is provided in e-Appendix 1.

    Funding/Support: This work was supported by Chiesi España.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

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