Cognitive dysfunction and its association with inflammation in acute exacerbations of COPD: protocol for a prospective hospital-based cohort.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is characterised by progressive airflow limitation that is not fully reversible and is associated with an abnormal inflammatory response of lungs to noxious particles and gases. The inflammatory and reparative processes occurring in the lungs induce a 'spill-over' of inflammatory mediators into the circulation, resulting in an increase in systemic inflammation, which is further increased during acute exacerbations of COPD (AECOPD), leading to the development of extra-pulmonary comorbidities, such as cognitive impairment. Cognitive impairment affects up to 61% of people living with COPD. Heightened levels of inflammation have been linked to increased risk of cognitive impairments; however, the exact mechanisms remain unclear, thus hampering the development of therapeutics. This study aims to determine whether patients hospitalised with an acute COPD exacerbation show impaired cognitive function compared with recovery (~day 45), and whether such dysfunction is associated with systemic inflammation and oxidative stress. METHODS AND ANALYSIS: A prospective, observational study will be conducted at Austin Health in Victoria, Australia. Eligible participants will be assessed during admission for AECOPD and following stabilisation (approximately day 45). The primary outcome is the difference in cognitive function between admission for AECOPD to recovery using non-verbal cognitive tests. Secondary outcomes are changes in systemic markers of inflammation, oxidative stress and ACE2 catalytic activity. Tertiary outcomes are anxiety and depression scores. ETHICS AND DISSEMINATION: Ethical approval has been granted in Australia by Austin Health Human Research Ethics Committee (HREC 56099) with governance approval at Austin Hospital. The results will be published in peer-reviewed scientific journals and presented at national and international scientific conferences. Findings will be disseminated to consumers in publications for lay audiences.