PREdictors of COVID-19 OUtcomeS (PRECIOUS): Protocol for a systematic review-informed individual participant data meta-analysis of long-term outcomes after COVID-19

Introduction: COVID-19 impacted individuals, healthcare services, governments, societies and economies. The long-term effects beyond acute illness and symptom persistence are not fully elucidated and require high-quality data to inform planning and resource allocation. The PREdictors of CovId OUtcomeS (PRECIOUS) database aims to collate and synthesise evidence related to long-term outcomes across the International Classification of Functioning, Disability and Health (ICF), describe predictors of poor long-term outcomes and associated costs to individuals, health systems and society in an individual participant data meta-analysis (IPDMA). Methods & Analysis: Systematic searching of electronic databases (Medline, CENTRAL, EMBASE, Web of Science, PsycINFO, CINAHL, WHO Global Index Medicus, Epistemonikos, LitCOVID); clinical trial registers (WHO ICTRP; clinicaltrials.gov) and backward and forward citation tracking, preprints, open data repositories and funding agencies will be used to identify studies that meet the following criteria: more than 10 participants in any setting, from cohort, case-control, survey or randomised controlled trials (RCT), that include a validated outcome measurement instrument, symptom data, hospitalisation, discharge destination or mortality beyond 28-day post-COVID-19 onset. Contributed datasets will be included in the PRECIOUS database. Available outcome assessment instruments will be inventoried and mapped to the ICF, describing evidence availability and gaps using an interactive gap-map; one-step IPDMA using stepwise regression will describe factors associated with outcomes by time, and the related costs for individuals, health systems, and society. Ethics & Dissemination: PRECIOUS will provide high-quality data on long-term outcomes across the ICF framework, predictors over time and associated costs. This will support the identification of targets for optimising management and resource allocation, producing data for future pandemic planning, directing future research and establishing a legacy dataset for further analyses. Ethical approval has been granted by Glasgow Caledonian University Ethics (HLS/NCH/20/04). Registration: PRECIOUS is funded by the UK National Institute of Health Research: 132895; PROSPERO: CRD42020224323; IRAS: 293578.