Hospital Admissions for Acute Exacerbations of Chronic Obstructive Pulmonary Disease; Contributing factors, Risk prediction and Prognosis

Background: Hospitalisations for acute exacerbations of Chronic Obstructive Pulmonary Disease (COPD) are associated with high mortality. Clinical indicators and prognostic scores have been explored previously to identify patients at heightened risk, but may also be useful in detecting patients with a good prognosis that could avoid admission. However, there are often additional social and environmental factors at play that influence patients’ reasons for admission. This thesis aims to explore these potential contributing factors in conjunction with the development of a new prognostic tool Methods: Consecutive patients were recruited following hospitalisation with a primary diagnosis of acute exacerbation of COPD. Clinical data were collected and patient and admitting doctor questionnaires were completed to gather further information regarding the reasons for admission. This cohort was then used to validate a proposed prognostic tool, the CANT score, comprised of a composite score of CURB65 score ≥ 2, Acidaemia (pH 220pmol/L and Troponin >0.03µg/L. The primary outcomes related to this score were all-cause mortality at 30-days and 1-year and cardio-respiratory related re-admissions over the same time period. Results: 305 patients were recruited across 3 New Zealand sites. The majority of patients had severe COPD as classified by the GOLD spirometry guidelines, and 13.5% of patients had long-term oxygen therapy at home prior to admission. Inpatient mortality was 1.6% (n=5). At 30-days post admission, mortality was 3.6% (n=11) and at 1-year 19.0% (n = 52). Readmissions for cardiac or respiratory related illnesses were 22.6% and 62.8% at 30-days and 1-year respectively. Raised NT-proBNP (>220pmol/L) and troponin (>0.03µg/L) on admission were associated with death at 1-year (p