Chest
Volume 128, Issue 4, October 2005, Pages 2005-2011
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Clinical Investigations
Comorbidity and Mortality in COPD-Related Hospitalizations in the United States, 1979 to 2001

https://doi.org/10.1378/chest.128.4.2005Get rights and content

Study objectives

COPD is one of the leading causes of mortality and morbidity in the United States, yet little is known about the prevalence of comorbid conditions and mortality in hospitalized patients with COPD.

Design

From the National Hospital Discharge Survey, 1979 to 2001, we evaluated whether or not COPD in adults ≥ 25 years old is associated with increased prevalence and in-hospital mortality of several comorbidities.

Results

During 1979 to 2001, there were an estimated total of 47,404,700 hospital discharges (8.5% of all hospitalizations in adults > 25 years old) of patients with COPD; 37,540,374 discharges (79.2%) were made with COPD as a secondary diagnosis, and 9,864,278 discharges (20.8%) were made with COPD as the primary diagnosis. The prevalence and in-hospital mortality for pneumonia, congestive heart failure, ischemic heart disease, thoracic malignancies, and respiratory failure were larger in hospital discharges with any mention of COPD.

Conclusions

In a nationally representative sample of hospitalizations, any mention of COPD in the discharge diagnosis is associated with higher hospitalization prevalence and in-hospital mortality from other comorbidities. These results highlight the fact that the burden of disease associated with COPD is likely underestimated.

Section snippets

Materials and Methods

The NHDS is a national survey that has been conducted continuously since 1965, and it provides data on inpatient utilization of non-Federal, short-stay hospitals in the United States. NHDS data are collected from a sample of inpatient records acquired from a national probability sample of hospitals. Because persons with multiple discharges during the year can be sampled more than once, the NHDS produces estimates for discharges, not persons. Only general hospitals, children's general hospitals,

Analysis

We used ICD-9 codes 490–492 and 496 to define COPD, and included COPD as either primary (first diagnosis listing) or secondary discharge diagnosis (from the second to the seventh diagnosis listing). We evaluated whether having a primary or secondary diagnosis of COPD in adults ≥ 25 years old was associated with increased prevalence and mortality from the following selected comorbidities: pneumonia (ICD-9 480–487.8); hypertension (ICD-9 401–406); diabetes (ICD-9 250); heart failure (ICD-9 428);

Results

During 1979 to 2001, there were an estimated total of 47,404,700 hospital discharges with a diagnosis of COPD as either the primary or secondary discharge diagnosis (8.5% of all hospitalizations in adults > 25 years old), of which 37,540,374 discharges (79.2%) were listed with COPD as a secondary diagnosis and 9,864,278 discharges (20.8%) were listed with COPD as the primary discharge diagnosis. From 1979 to 2001, the yearly prevalence of hospital discharges with a diagnosis of COPD increased

Discussion

COPD is one of the leading causes for mortality and morbidity in the United States, yet little is known about the prevalence of comorbid conditions and specific causes of death in hospitalized patients with COPD.8 In this analysis, hospital discharges with primary or secondary COPD were also more frequently diagnosed with other comorbid conditions, including cardiac and pulmonary vascular disease, pneumonia, and thoracic malignancies. Also, the in-hospital mortality from congestive heart

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This work was performed at the Centers for Disease Control and Prevention, Air Pollution and Respiratory Health Branch.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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