Statistically significant lower risk is seen for mortality, hospitalization, and cases. 12 studies from 12 independent teams in 5 countries show significant improvements.
Meta analysis using the most serious outcome reported shows 30% [22‑38%] lower risk. Results are similar for peer-reviewed studies.
Results are very robust — in exclusion sensitivity analysis 13 of 15 studies must be excluded to avoid finding statistically significant efficacy in pooled analysis.
Studies analyze sleep quality before infection, and use different definitions of sleep quality.
No treatment or intervention is 100% effective. All practical, effective, and safe means should be used based on risk/benefit analysis.
All data to reproduce this paper and sources are in the appendix. Zhou et al. present another meta analysis for sleep quality, showing significant improvements for mortality, hospitalization, cases, and long COVID with higher quality sleep.
Covid Analysis et al., Oct 2024, preprint, 1 author.