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

ObjectiveThe 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. IntroductionMortality 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 criteriaThe 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. MethodsA 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.