Risk Factors for Excess Deaths Among Older Adults Without Confirmed COVID-19 During Lockdown: A Retrospective Cohort Study

Abstract

Background: Besides deaths directly attributable to COVID-19, many excess deaths occurred during ‘lockdown’, the range of societal responses to the initial wave of the COVID-19 pandemic. Data regarding these excess deaths is sparse, but necessary in order to avoid them in future waves. We investigated what factors contributed to excess deaths of older patients during the initial 2020 lockdown beyond those attributable to confirmed COVID-19. We hypothesized that both physical diseases and mental disorders would contribute.Methods: We did a retrospective cohort study using data from the electronic clinical records from Cambridge and Peterborough NHS Foundation Trust (CPFT), UK (catchment area population ~ 0.86 million). Eligible patients were aged 65 years or over at baseline with at least 14 days’ follow-up, excluding patients diagnosed with confirmed or suspected SARS-CoV-2 infection. We defined a cohort exposed to COVID-19 lockdown comprising patients recorded in CPFT between March 23, 2020 and May 19, 2020, and compared their mortality with an cohort recorded in CPFT between January 13, 2020 and 10 March, 2020, unexposed to lockdown. We used Cox regression to estimate the association between risk factors and death. Controlled covariates included social demographic factors, smoking status, mental comorbidities, and physical comorbidities.Findings: In the two cohorts, 3,073 subjects were exposed to lockdown and 4,372 subjects were unexposed; the cohorts were followed up for an average of 74 days and 78 days, respectively. After controlling for confounding by sociodemographic factors, smoking status, mental comorbidities, and physical comorbidities, dementia patients suffered an additional 53% risk of death (HR = 1.53, 95% CI = 1.02-2.31), and patients with severe mental illness suffered an additional 123% risk of death (HR = 2.23, 95% CI = 1.42-3.49). No significant additional death risks were identified from physical comorbidities.Interpretation: During lockdown people with dementia or severe mental illness had a higher risk of excess death. This study suggests that such patients require additional support during a societal response to this and similar epidemics/pandemics. These data could inform future health service responses and policymaking to help prevent avoidable excess death during future outbreaks of similar infectious diseases.Funding Statement: SC’s, PBJ’s, and RNC’s research was supported by the Medical Research Council (grant MC_PC_17213 to RNC). PBJ is funded through the NIHR Applied Research Collaboration (ARC) East of England. This research was supported in part by the UK National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre. Declaration of Interests: SC, EFE, PQ, and JRL declare no conflict of interest with this work. PBJ is a scientific advisory board member for Janssen and Recordati. BRU is clinical director for older people’s and adult community services at CPFT. He is clinical director of the Windsor Unit at Fulbourn Hospital (CPFT), which delivers clinical trials in dementia/mild cognitive impairment for academic and commercial organisations without personal benefit, and is the clinical lead for dementia for the NIHR Clinical Research Network (CRN) in the East of England. His salary is part-funded by the NIHR CRN. He has been principal investigator on trials for Axovant, Lilly, and EIP Pharma; his institution has benefited from payment for research carried out but he has not personally received any money. His wife is the lead for mental health for Suffolk Clinical Commissioning Group. RNC consults for Campden Instruments Ltd and receives royalties from Cambridge University Press, Cambridge Enterprise, and Routledge.Ethics Approval Statement: NHS Research Ethics 17/EE/0442