The clinical implications of tests confirming COPD in subjects hospitalized with exacerbations

ABSTRACT

Background: The diagnosis of COPD in patients hospitalized for AECOPD can be confirmed by spirometry showing obstruction or radiographs showing emphysema. The evidence for COPD is sometimes absent or contradicts this diagnosis. The inaccurate attribution of the exacerbation to COPD can lead to suboptimal care and worse outcome.

Objectives: We determined if the presence of tests that confirm the diagnosis of COPD has any implications on the course of the hospitalization and readmission rate.

Methods: We selected subjects hospitalized between 2012 and 2014 for AECOPD. We divided them into four hierarchical, mutually exclusive groups based on the presence of tests that confirm the diagnosis of COPD: spirometry (COPD_SPIRO), radiology (COPD_RAD), clinical diagnosis (COPD_CLIN), and no COPD by spirometry (NotCOPD). We compared the presentation, hospital course, outcome, and readmission rate between the four groups.

Results: We identified 974 subjects: COPD_SPIRO 22%, COPD_RAD 24%, COPD_CLIN 46% and 7% NotCOPD. The vital signs, use of respiratory support, admission to the MICU, and length of stay were similar between the groups. The age, gender, BMI, presence of comorbidities, and readmission rate were different between the groups. The NotCOPD group had the highest BMI (38 kg/m²), comorbidities, and 30-day all-cause readmission (17%). Logistic regression showed that serum creatinine and presence of any comorbidity were the independent predictors of 30-day all-cause readmission.

Conclusion: COPD was confirmed by spirometry or radiographs in half of the subjects hospitalized for AECOPD. The presence of confirmation did not influence the hospital course. The presence of confirmation was associated with different readmission rate, but was accounted for by the presence of comorbidities.

KEYWORDS:

• AECOPD
• spirometry
• accurate diagnosis
• readmission

Acknowledgments

We would like to thank Ms Helen Zhang and Dr William Trick from Clinical Research Unit of John H.Stroger Hospital for providing us with the list of subjects. We also thank Dr William Clapp for providing us the pulmonary function test (PFT) data.

Declaration of interest

The authors have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article. Hospital Practice peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Notes on contributions

CYP: responsible for the content of the manuscript, including the data analysis, conception and design, data acquisition, analysis and interpretation of data, and draft and revision of submitted manuscript. NQ: conception and design, data interpretation of data and revision of submitted manuscript. RN: conception and design, data acquisition, analysis and interpretation of data and draft and revision of submitted manuscript. KA: data acquisition, analysis and interpretation of data and draft and revision of submitted manuscript. AT: conception and design, data analysis and interpretation of data and revision of submitted manuscript.

Previous presentations

Poster presented in ATS 2016 Conference in San Francisco by CYP.

Supplementary data

Supplementary data can be accessed here.

Additional information

Funding

This manuscript was not funded.