Long-term Impact of the COVID-19 Pandemic on Self-management of Chronic Conditions Among High-risk Adults in the USA: Protocol for the C3 Observational Cohort Study

Introduction: COVID-19 is an unprecedented public health threat in modern times, especially for older adults or those with chronic illness. Beyond the threat of infection, the pandemic may also have longer-term impacts on mental and physical health. The COVID-19 & Chronic Conditions ('C3') study offers a unique opportunity to assess psychosocial and health/healthcare trajectories over 5 years among a diverse cohort of adults with comorbidities well-characterised from before the pandemic, at its onset, through multiple surges, vaccine rollouts and through the gradual easing of restrictions as society slowly returns to 'normal'.

Methods And Analysis: The C3 study is an extension of an ongoing longitudinal cohort study of 'high-risk' adults (aged 23-88 at baseline) with one or more chronic medical conditions during the COVID-19 pandemic. Five active studies with uniform data collection prior to COVID-19 were leveraged to establish the C3 cohort; 673 adults in Chicago were interviewed during the first week of the outbreak. The C3 cohort has since expanded to include 1044 participants across eight survey waves (T-T). Four additional survey waves (T-T) will be conducted via telephone interviews spaced 1 year apart and supplemented by electronic health record and pharmacy fill data, for a total of 5 years of data post pandemic onset. Measurement will include COVID-19-related attitudes/behaviours, mental health, social behaviour, lifestyle/health behaviours, healthcare use, chronic disease self-management and health outcomes. Mental health trajectories and associations with health behaviours/outcomes will be examined in a series of latent group and mixed effects modelling, while also examining mediating and moderating factors.

Ethics And Dissemination: This study was approved by Northwestern University's Feinberg School of Medicine Institutional Review Board (STU00215360). Results will be published in international peer-reviewed journals and summaries will be provided to the funders of the study.