Explanations for higher-than-expected mortality from April 2021: a scoping review protocol

Objective The objective of this scoping review is to identify the explanations that have been proposed for higher-than-expected mortality following the first pandemic year, and any evidence to support or refute these explanations. Introduction Mortality rates have remained high compared to previous years, beyond the peak waves of Covid-19 mortality. Several explanations have been suggested for this. Identifying potential hypotheses and empirical studies investigating these is the first step before any further analytical work to investigate these trends can be undertaken. Inclusion criteria The scoping review will include papers proposing or investigating hypotheses for raised all cause or cause specific mortality, or reduced life expectancy, from April 2021 onwards compared to pre-pandemic levels. It will include papers on mortality in the whole population or any specific demographic sub-populations, in high income countries only, but exclude studies of mortality or survival following a healthcare intervention. Methods A systematic search will be undertaken on Medline, Embase and Google Scholar for relevant articles published from 2021 onwards in English, with a similar search for grey literature on relevant government websites. Two reviewers will screen titles and abstracts, then full text articles with disagreements resolved by discussion or involvement of a third reviewer. Data extracted from selected articles will include the setting, population, hypothesis/es proposed, study type and findings if relevant. Included papers will be tabulated against the proposed hypotheses with any empirical evidence and hypotheses summarised narratively. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work has not received any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes This is a review protocol and no data have been produced