Bidirectional relationship between sleep problems and long COVID: a longitudinal analysis of data from the COVIDENCE UK study

Abstract

BACKGROUND: Studies into the bidirectional relationship between sleep and long COVID have been limited by retrospective pre-infection sleep data and infrequent post-infection follow-up. We therefore used prospectively collected monthly data to evaluate how pre-infection sleep characteristics affect risk of long COVID and to track changes in sleep duration during the year after SARS-CoV-2 infection. METHODS: COVIDENCE UK is a prospective, population-based UK study of COVID-19 in adults. We included non-hospitalised participants with evidence of SARS-CoV-2 infection and used logistic regression to estimate adjusted ORs for the association between preinfection sleep characteristics and long COVID. We assessed post-infection sleep duration using multilevel mixed models. We collected sleep data from participants using a subset of questions from the Pittsburgh Sleep Quality Index. We defined long COVID as unresolved symptoms at least 12 weeks after infection. COVIDENCE UK is registered with ClinicalTrials.gov, NCT04330599. RESULTS: We included 3994 participants in our long COVID risk analysis, of whom 327 (8.2%) reported long COVID. We found an inverse relationship between pre-infection sleep quality and risk of long COVID (medium vs good quality: OR 1.37, 95% CI 1.04 to 1.81; medium-low vs good: 1.55, 1.12 to 2.16; low vs good: 1.94, 1.11 to 3.38). Greater variability in pre-infection sleep efficiency was also associated with long COVID when adjusted for infection severity (OR per percentage-point increase 1.07, 1.02 to 1.12). We assessed post-infection sleep duration in 6860 participants, observing a 0.11 hour (95% CI 0.09 to 0.14) increase in the first month after infection compared with pre-infection, with larger increases for more severe infections. After 1 month, sleep duration largely returned to pre-infection levels, although fluctuations in duration lasted up to 6 months after infection among people reporting long COVID. CONCLUSIONS: While poor-quality sleep before SARS-CoV-2 infection associates with increased risk of long COVID thereafter, changes in sleep duration after infection in these non-hospitalised cases were modest and generally quick to resolve. TRIAL REGISTRATION NUMBER: NCT04330599.