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The CODEX IndexCODEX: A Collection or Digest of Laws: A Code FREE TO VIEW

Gavin C. Donaldson, PhD; Jadwiga A. Wedzicha, MD
Author and Funding Information

From the Centre for Respiratory Medicine, University College London, Royal Free Hospital.

Correspondence to: Gavin C. Donaldson, PhD, Centre for Respiratory Medicine, University College London, Royal Free Hospital, Rowland Hill St, London, NW3 2PF, England; e-mail: g.donaldson@ucl.ac.uk


Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

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


Chest. 2014;145(5):934-935. doi:10.1378/chest.13-2678
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Prognostic scoring systems are useful in clinical practice to identify patients at highest risk from death, to support decisions regarding how aggressively to intervene with therapies, or to inform decisions that palliative care is in the patient’s best interest. The scores can also be used to stratify patients for inclusion into clinical trials, the results from which will hopefully improve care and life expectancy.

The recent updates to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) strategy documents on COPD have placed much more emphasis on multidimensional assessment tools and future risk reduction associated with COPD, including improved management and prevention of COPD exacerbations.1 These events are key events in the natural history of COPD and are important causes of morbidity and mortality in the condition. Some patients are especially susceptible to development of exacerbations and are termed frequent exacerbators with increased airway and systemic inflammation and worse prognosis than patients with a history of infrequent exacerbations.2 Frequent exacerbators have a higher risk of hospital admission and also recurrent exacerbations3 causing hospital readmission especially within 3 months of an index admission, which is costly for health-care services all over the world. In a large Canadian COPD database study, Suissa and colleagues4 also showed that from one hospital admission to the next, with progressive disease, the chance of readmission increases.

Thus, the study by Almagro and colleagues5 in this issue of CHEST (see page 972) concerning a scoring system to predict early readmission to hospital and mortality in patients with COPD is much needed and, thus, welcomed. The study—which includes results from a development cohort of patients with COPD in Spain, its implementation in a validation cohort, and a comparison with other scoring systems—is a model for how to both devise and report such a prognostic scoring system.

The CODEX index is based on comorbidity, age, obstruction, dyspnea, and previous severe exacerbations. Its main novelty is the inclusion of the Charlson comorbidity score coupled with one extra point per decade of life. This must be correct as any prediction of mortality disregarding age and comorbidity is probably doomed to failure. The authors have clearly demonstrated its advantages over other indexes, such as the well-known BODEX (BMI, airflow obstruction, dyspnea, and previous severe exacerbations),6,7 DOSE (dyspnea, airflow obstruction, smoking status, and exacerbation frequency),8 and ADO (age, dyspnea, and airflow obstruction)9 instruments over the short to medium term in high-risk patients with severe COPD. The other scoring systems are slightly simpler, and possibly better, in classifying patients with mild and moderate COPD who are mainly seen in primary care, where there is limited time and at a stage in COPD management when patients are not yet at risk for being regularly admitted to hospital for an acute exacerbation.

It is not surprising that the CODEX scores are useful in predicting both hospitalized exacerbations and mortality. These two outcome measures are in fact closely correlated. Soler-Cataluña and colleagues10 showed that the hospitalized COPD exacerbation rate, split into tertiles, predicted mortality independently of FEV1, age, and comorbidity. However, the strength of the relationship may decline with time, as mortality rates that are high immediately postadmission to hospital may decline during the recovery period. The prediction of those at greatest risk of hospital admission is important as the health-care costs associated with a hospitalized exacerbation are 10 times those requiring an unscheduled visit to a physician and 100 times those for self-management in the community with a course of antibiotics or oral corticosteroids.11

With any prognostic system, it is wise to remember that being able to describe the past is not the same as being able to predict the future. New therapeutic strategies may alter survival and readmission times, and, of course, use of the CODEX prediction might alter the outcome. Furthermore, how the CODEX index works in the real world will be important. Indeed, data are generally absent on whether any of the scoring systems are being widely adopted by respiratory physicians in their routine clinical practice outside of major research centers.

The article by Almagro and colleagues5 has set a high standard and indeed a potential barrier to the development of any more prognostic tools in COPD. Significant but only small improvements in the predictive powers of any set of variables should not now justify publication. It is time to see whether these tools are actually affecting clinical practice and, thus, helping our patients with COPD to improve their quality of life and outcomes.

References

Vestbo J, Hurd SS, Agustí AG, et al. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary. Am J Respir Crit Care Med. 2013;187(4):347-365. [CrossRef] [PubMed]
 
Wedzicha JA, Brill SE, Allinson JP, Donaldson GC. Mechanisms and impact of the frequent exacerbator phenotype in chronic obstructive pulmonary disease. BMC Med. 2013;11:181. [CrossRef] [PubMed]
 
Hurst JR, Donaldson GC, Quint JK, Goldring JJP, Baghai-Ravary B, Wedzicha JA. Temporal clustering of exacerbations in chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2009;179(5):369-374. [CrossRef] [PubMed]
 
Suissa S, Dell’Aniello S, Ernst P. Long-term natural history of chronic obstructive pulmonary disease: severe exacerbations and mortality. Thorax. 2012;67(11):957-963. [CrossRef] [PubMed]
 
Almagro P, Soriano JB, Cabrera FJ, et al; Working Group on COPD, Spanish Society of Internal Medicine. Short- and medium-term prognosis in patients hospitalized for COPD exacerbation: the CODEX index. Chest. 2014;145(5):972-980.
 
Celli BR, Cote CG, Marin JM, et al. The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med. 2004;350(10):1005-1012. [CrossRef] [PubMed]
 
Soler-Cataluña JJ, Martínez-García MA, Sánchez LS, Tordera MP, Sánchez PR. Severe exacerbations and BODE index: two independent risk factors for death in male COPD patients. Respir Med. 2009;103(5):692-699. [CrossRef] [PubMed]
 
Jones RC, Donaldson GC, Chavannes NH, et al. Derivation and validation of a composite index of severity in chronic obstructive pulmonary disease: the DOSE index. Am J Respir Crit Care Med. 2009;180(12):1189-1195. [CrossRef] [PubMed]
 
Puhan MA, Garcia-Aymerich J, Frey M, et al. Expansion of the prognostic assessment of patients with chronic obstructive pulmonary disease: the updated BODE index and the ADO index. Lancet. 2009;374(9691):704-711. [CrossRef] [PubMed]
 
Soler-Cataluña JJ, Martínez-García MA, Román Sánchez P, Salcedo E, Navarro M, Ochando R. Severe acute exacerbations and mortality in patients with chronic obstructive pulmonary disease. Thorax. 2005;60(11):925-931. [CrossRef] [PubMed]
 
Borg S, Ericsson A, Wedzicha J, et al. A computer simulation model of the natural history and economic impact of chronic obstructive pulmonary disease. Value Health. 2004;7(2):153-167. [CrossRef] [PubMed]
 

Figures

Tables

References

Vestbo J, Hurd SS, Agustí AG, et al. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary. Am J Respir Crit Care Med. 2013;187(4):347-365. [CrossRef] [PubMed]
 
Wedzicha JA, Brill SE, Allinson JP, Donaldson GC. Mechanisms and impact of the frequent exacerbator phenotype in chronic obstructive pulmonary disease. BMC Med. 2013;11:181. [CrossRef] [PubMed]
 
Hurst JR, Donaldson GC, Quint JK, Goldring JJP, Baghai-Ravary B, Wedzicha JA. Temporal clustering of exacerbations in chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2009;179(5):369-374. [CrossRef] [PubMed]
 
Suissa S, Dell’Aniello S, Ernst P. Long-term natural history of chronic obstructive pulmonary disease: severe exacerbations and mortality. Thorax. 2012;67(11):957-963. [CrossRef] [PubMed]
 
Almagro P, Soriano JB, Cabrera FJ, et al; Working Group on COPD, Spanish Society of Internal Medicine. Short- and medium-term prognosis in patients hospitalized for COPD exacerbation: the CODEX index. Chest. 2014;145(5):972-980.
 
Celli BR, Cote CG, Marin JM, et al. The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med. 2004;350(10):1005-1012. [CrossRef] [PubMed]
 
Soler-Cataluña JJ, Martínez-García MA, Sánchez LS, Tordera MP, Sánchez PR. Severe exacerbations and BODE index: two independent risk factors for death in male COPD patients. Respir Med. 2009;103(5):692-699. [CrossRef] [PubMed]
 
Jones RC, Donaldson GC, Chavannes NH, et al. Derivation and validation of a composite index of severity in chronic obstructive pulmonary disease: the DOSE index. Am J Respir Crit Care Med. 2009;180(12):1189-1195. [CrossRef] [PubMed]
 
Puhan MA, Garcia-Aymerich J, Frey M, et al. Expansion of the prognostic assessment of patients with chronic obstructive pulmonary disease: the updated BODE index and the ADO index. Lancet. 2009;374(9691):704-711. [CrossRef] [PubMed]
 
Soler-Cataluña JJ, Martínez-García MA, Román Sánchez P, Salcedo E, Navarro M, Ochando R. Severe acute exacerbations and mortality in patients with chronic obstructive pulmonary disease. Thorax. 2005;60(11):925-931. [CrossRef] [PubMed]
 
Borg S, Ericsson A, Wedzicha J, et al. A computer simulation model of the natural history and economic impact of chronic obstructive pulmonary disease. Value Health. 2004;7(2):153-167. [CrossRef] [PubMed]
 
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