Completed Projects A study of the association of acute illness hospitalisation (AIH) on the long-term cognitive trajectory of the Sydney Memory and Aging Study (MAS) participants (PhD conferred 10 June 2021) CHeBA staff: L N Premilla Chinnappa-Quinn, Perminder Sachdev, Nicole Kochan, John Crawford, Steve Makkar (until Oct 2019), Ben Lam (assistance from Jessica Lo for meta-analysis). Other investigators: Michael Bennett (Prince of Wales Clinical School, UNSW), Lara Harvey (NeuRA). Aims: • To examine the association of AIH exposure and posthospitalisation cognitive decline (PHCD) in older age adults; • to characterise the association of recent AIH exposure and PHCD; • to compare the association of specific types of AIH exposure and PHCD (surgical and non-surgical AIH and AIH complicated by delirium); • to examine the influence of AIH characteristics such as length of stay on the association with PHCD; to examine the influence of patient characteristics (e.g., age, education, sex, comorbidities, Apolipoprotein E 4 allele (APOE*4)) on these associations. Findings: • The first part of the literature review for this PhD project has been published and summarises studies investigating cognition following surgical, critical care AIH and AIH complicated by delirium: Chinnappa-Quinn L, Bennett M, Makkar SR, Kochan NA, Crawford JD, Sachdev PS. Is hospitalisation a risk factor for cognitive decline in the elderly? Curr Opin Psychiatry. 2019; Published Ahead of Print. • The second part of the literature review describes a systematic review of peer reviewed papers investigating the association of AIH and post-discharge cognition from Medline, Embase, Psycinfo and CINAHL, screening 6566 titles and abstracts. We synthesized results from 46 papers. Most papers were prone to bias as a result of have no baseline cognition data or appropriate comparison groups. However, eight studies used community cognition data and most of these showed cognitive decline associated with acute hospitalisations. Seven studies were able to be pooled statistically and the meta-analysis also supported this finding that acute hospitalisation increased cognitive decline, in particular conversion to dementia in subsequent years. This metaanalysis has been published: Chinnappa-Quinn L, Makkar SR, Bennett M, Lam BCP, Lo JW, Kochan NA, et al. Is hospitalization a risk factor for cognitive decline in older age adults? International Psychogeriatrics. 2020:1-18.
• Latent growth modelling was used to estimate global cognition latent intercept and slope from neuropsychological data in four biennial waves. Electronically linked hospitalisation data from the New South Wales Admitted Patient Data Collection were computed in time intervals to clarify recency effects. Overall AIH effect, as well as surgical, medical and AIH with delirium exposures were investigated. A novel approach was taken to include concurrent hospitalisation variables in the same model to allow effects to overlap and use continuous variables to quantify effects accurately. The sample (n = 1026) had a mean age of 78.8 years, a mean Mini-Mental State Examination score of 28.7 and was functionally independent. Over ten years, 82% were hospitalised with a mean of 1.7 medical and 1.6 surgical hospitalisations. Their mean global cognition z-score decline per year was -0.105. Recent AIH exposure was associated with an increased rate of decline (-0.014 ± 0.005 global cognition z-score per year; p = .008). The number of AIH episodes had a greater association with cognitive decline than length of stay in hospital in days. This association was greater for medical admissions and especially so for AIH complicated by delirium, even for non-neurological AIH. Conversely, surgical AIH were not associated with cognitive decline, when compared to those without hospitalisations. This confirms emerging evidence that post-operative cognitive dysfunction is a mild subset of post-hospitalisation cognitive decline. Delirium, however, emerged as the most potent association with accelerated decline and warrants further investigation and more proactive intervention to reduce its incidence. Further Analyses: • To examine the association of AIH exposure and PHCD in older age adults with regards to cognitive domains, subjective cognitive complaints and risk of dementia and MCI • To examine the association of the effect of recency of hospitalisation in a short-term context to PHCD, by grouping hospitalisations by timing in relation to subsequent MAS cognitive wave assessments • To examine the association of prehospitalisation cognition and risk of AIH Funding: Australian Society of Anaesthetists, DCRC-ABC.
Apolipoproteins in plasma (particularly APOA1, APOD, APOJ and APOH) CHeBA staff: Anne Poljak (Adjunct), Tharusha Jayasena, Nicole Kochan, Wei Wen, John Crawford, Fei Song, Julian Trollor (conjoint), Henry Brodaty, Perminder Sachdev. Other investigators: Dr Julia Muenchhoff (CHeBA Hon. Research Fellow), Professor John Attia (University of Newcastle), Professor Mark Duncan (University of Colorado), Professor Ralph Martins (Edith Cowan University), Associate Professor Mark McEvoy (University of Newcastle), Associate Professor Peter W. Schofield (University of Newcastle), Dr Tamar Ziehm (visiting research fellow from Forschungszentrum Jülich, Germany), Professor Dieter Willbold (collaborating researcher from Forschungszentrum Jülich, Germany),
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