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Risk Factors for Repeat Healthcare Use following Hospitalisation with an Acute Exacerbation of Chronic Obstructive Pulmonary Disease

posted on 13.11.2020, 12:10 by Breda Cushen
Chronic Obstructive Pulmonary Disease (COPD) is one of the leading causes of death
worldwide. Up to one-tenth of patients hospitalised with a COPD exacerbation die
during admission and, of those surviving to discharge, more than one-third will be
readmitted within 90 days with many more treated for a repeat exacerbation in the
emergency department or in the community. These figures are reported universally,
despite significant variation in the access to, structure and resources of healthcare
systems across different jurisdictions. However, even with the high frequency of
exacerbations, and the severity of their consequences, they remain poorly understood
and poorly studied. Furthermore, there is no robust clinical predictive tool to aid
physicians in their assessment of who is most at risk at the time of hospital discharge.
In this thesis, I explore the reasons why so many patients hospitalised with an
exacerbation of COPD experience a repeat exacerbation within 90-days of discharge.
By using change in respirable lung volume as a marker of treatment response, I
successfully test the hypothesis that the risk of repeat exacerbation in COPD is
increased in patients whose exacerbation has failed to adequately recover by the time
of hospital discharge. In addition, I discuss the derivation of a clinical score, the
COPD-2-HOME score, which incorporates treatment response, as determined by
change in lung volumes, symptoms, underlying disease severity, prior healthcare use
and the presence of stable state eosinophilia, to estimate the risk of 90-day
moderate-severe COPD exacerbation at the time of hospital discharge. I demonstrate
how the five point COPD-2-HOME score can reliably stratify patients into groups of
Low, Intermediate and High risk of re-exacerbation, through its external validation in
three multinational study cohorts. I also explore other potential reasons for the high
rates of healthcare use amongst COPD patients, which were not captured in the
derivation study, including variations in adherence to inhaled therapies, and examine
the relationship of distinct adherence behaviours to clinical outcomes in this cohort.
Finally, I discuss the implications of this work and propose a new strategy for the
future management of patients hospitalised with an acute exacerbation of COPD.


First Supervisor

Professor Richard W Costello

Second Supervisor

Dr. Emer Kelly


A thesis submitted for the degree of Doctor of Philosophy from the Royal College of Surgeons in Ireland in 2019.

Published Citation

Cushen B. Risk Factors for Repeat Healthcare Use following Hospitalisation with an Acute Exacerbation of Chronic Obstructive Pulmonary Disease [PhD Thesis]. Dublin: Royal College of Surgeons in Ireland; 2019.

Degree Name

Doctor of Philosophy (PhD)

Date of award



  • Doctor of Philosophy (PhD)

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