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30-05-2013 | Respiratory | Article

COPD, comorbidities linked to poor hospitalization outcomes


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medwireNews: Data from the Swiss population show that patients with chronic obstructive pulmonary disease (COPD) who are hospitalized experience poorer outcomes than patients without COPD, even if the condition was not the reason they were admitted.

In addition, the researchers show that comorbidities tend to cluster in COPD patients, creating distinct disease phenotypes.

"A better knowledge of such phenotypes might lead to a better understanding of the shared underlying disease mechanisms," say Martin Brutsche (Cantonal Hospital, St Gallen, Switzerland) and colleagues.

They add: "Such phenotyping might complement conventional COPD-phenotypes like 'pink puffer' or 'blue bloater', sometimes considered as over-simplified notions."

The authors identified 340,948 hospital admissions of patients with a COPD diagnosis from a total of 12,888,075 hospital admissions in Switzerland between 2002 and 2010. Overall, COPD was the main diagnosis in 71,191 (21%) of admissions among COPD patients.

When compared with controls matched for age, gender, and month of hospitalization, patients with COPD had over twice as many comorbidities, at an average of seven versus three. They also had a significantly higher rehospitalization rate at 0.33 versus 0.25 hospitalizations per year, a longer median hospital stay of 9 versus 5 days, and a greater rate of in-hospital mortality, at 5.9% versus 3.4%.

Brutsche and colleagues identified several concomitant conditions that were overrepresented among patients with COPD, including malignant lung neoplasms, tobacco or alcohol dependency, heart disease, asthma, obesity, and sleep apnea. Some of these comorbidities independently increased the risk for poor outcome; for example, COPD patients with malignant lung neoplasm, pulmonary heart disease, atrial fibrillation, or heart failure were significantly more likely to die in hospital than those without the comorbidities.

However, COPD patients who had no comorbidities still fared worse than controls with a single diagnosis, experiencing a longer median length of stay, a 2.7-fold greater risk for in-hospital death, and a 4.2-fold increase risk for rehospitalization.

Additionally, the authors show that comorbidities in patients with COPD tend to cluster together. For example, anxiety, depression, and mental and behavioral disorders frequently correlated with alcohol and tobacco dependency.

They also found that COPD subtypes were associated with different comorbidities. For example, the emphysema subtype was most commonly associated with respiratory failure, pulmonary heart disease, and cachexia, while the chronic bronchitis subtype was more commonly associated with obesity, Type 2 diabetes, and arterial hypertension.

Writing in PLoS One, the authors say that these findings seem to indicate that COPD worsens patient outcomes. "However, the more likely explanation of this phenomenon is that COPD could be an indicator of complex disease with a shared pathogenic mechanism," they write.

They conclude: "When treating patients with COPD, a special focus on early detection and treatment of comorbidities might improve overall outcome."

medwireNews ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013

By Kirsty Oswald, medwireNews Reporter

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