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

Objectives Many countries have continued to experience a higher-than-expected number of deaths following the peaks in mortality observed in the first year of the Covid-19 pandemic. This scoping review aims to identify the different explanations proposed for sustained higher-than-expected mortality beyond the first pandemic year. Study design Scoping review Methods A systematic search of databases and grey literature sources was completed to identify English-language records proposing or investigating hypotheses for higher-than-expected mortality from April 2021 onwards in (sub)populations of high-income countries. Papers focused on survival following a diagnosis or intervention were excluded. Results were summarised narratively, and existing research prioritisation frameworks were adapted and applied to identify the hypotheses proposed as highest priority for further research. Results Seventy eligible papers were identified. Most were opinion pieces or simply presented trends; few included investigation of suggested hypotheses. Numerous explanations for higher-than-expected mortality were proposed, with hypotheses relating to direct Covid-19 mortality, sequalae of Covid-19 infection, the health service impacts of the pandemic, wider pandemic impacts and socioeconomic factors identified as highest-priority for further research. Conclusions The causes of continued higher-than-expected mortality are likely to be multiple and potentially interactive. This review will help to shape research into current mortality trends, with a critical understanding of this topic essential for achieving evidence-informed policy. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Protocols ### Funding Statement This study did not receive 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I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the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 All data produced in the present study are available upon reasonable request to the authors.