CODEXS: A New Multidimensional Index to Better Predict Frequent COPD Exacerbators with Inclusion of Depression Score

Abstract

Purpose

Depression is reported in association with chronic obstructive pulmonary disease (COPD). However, to date, no multidimensional indices have taken depression into consideration to predict COPD patients’ prognosis. This study aimed to determine whether a new multidimensional index named CODEXS, based on comorbidities, airflow obstruction, dyspnea, previous exacerbation and depression assessed by Self-Rating Depression Scale (SDS), could predict 1-year exacerbations.

Methods

This was a prospective study, patients with stable COPD were used to develop CODEXS at the first visit, and followed up in the 3rd, 6th, and 12th months. After the last visit, patients were divided into frequent and infrequent exacerbators. Another cohort of COPD patients was used for validation. The SDS scoring system in the multidimensional indices ranged from 0 to 4 based on the modified SDS value, representing no depression (25–39 [0], 40–49 [1]), mild depression (50–59), moderate depression (60–69), and severe depression (≥70). Comorbidity, dyspnea, airflow obstruction, and severe exacerbations were calculated according to CODEX thresholds.

Results

Two sets of 105 and 107 patients were recruited in the development and validation cohorts, respectively. Depression was demonstrated as an independent risk factor for frequent exacerbators (odds ratio (OR)= 1.14, 95% confidence interval (CI) = 1.06–1.23, P < 0.001). The prevalence of depression in frequent exacerbators (35.09%) was higher than that in infrequent exacerbators. CODEXS was significantly associated with exacerbation (OR =2.91; 95% CI, 1.89–4.48, p<0.001). Receiver operating characteristic (ROC) curve comparison showed that CODEXS was superior to BODEX(BMI, airflow obstruction, dyspnea, previous exacerbation), BODE (BMI, airflow obstruction, dyspnea, exercise), and updated ADO (age, dyspnea, and airflow obstruction) indices, confirmed by the validation cohort with sensitivity at 85.94% and specificity at 76.74%.

Conclusion

Depression is an independent risk factor for COPD exacerbation. CODEXS is a useful predictor for predicting frequent exacerbators within 1 year and is superior to other previously published indices.

Keywords:

• COPD
• depression
• Self-Rating Depression Scale
• exacerbation
• CODEXS

Acknowledgments

This study was funded by grants from the Fundamental Research Funds for the Central Universities of Central South University (2017zzts228 to Doctor Aiyuan Zhou). We want to thank Dr. Alexandra Racanelli (Division of Pulmonary and Critical Care Medicine, Weill Cornell Medical College) for proofreading the manuscript. Dingding Deng and Aiyuan Zhou are co-first authors for this study.

Abbreviations

ADO, age, dyspnea, airflow obstruction; ADOS, age, dyspnea, airflow obstruction, depression; AECOPD, acute exacerbations of chronic obstructive pulmonary disease; AUC, area under the curve; BMI, body mass index; BODE, body mass index, airflow obstruction, dyspnea, exercise; BODES, body mass index, airflow obstruction, dyspnea, exercise, depression; BODEX, body mass index, airflow obstruction, dyspnea, previous severe exacerbation; BODEXS, body mass index, airflow obstruction, dyspnea, previous severe exacerbation, depression; CAT, COPD assessment test; CCQ, Clinical COPD Questionnaire; CES-D, Center for Epidemiologic Studies Depression Scale; CI, confidence interval; CODEX, comorbidities, airflow obstruction, dyspnea, previous severe exacerbation; CODEXS, comorbidities, airflow obstruction, dyspnea, previous severe exacerbation, depression; COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; GDS, Geriatric Depression Scale; GOLD, Global Initiative of Chronic Obstructive Lung Disease; HADS, Hospital Anxiety and Depression Scale; mMRC, modified Medical Research Council Dyspnea Scale; OR, odds ratio; ROC, receiver operating characteristic; SD, standard deviation; SDS, Self-Rating Depression Scale.

Data Sharing Statement

The authors confirm that the data supporting the findings of this study are available within the article. The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request, the authors will not share any individual deidentified participant date or other relevant study documents.

Ethics Approval and Consent to Participate

The research protocol was approved by the local Ethics Committee of the First Affiliated People’s Hospital of Shaoyang College (number: C2016123) and conducted in accordance with the Declaration of Helsinki and its amendments. All subjects gave written informed consent to participate in the study.

Author Contributions

All authors contributed to data analysis, drafting and revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.