The role of pre-infection sleep quality/duration and insomnia severity in the incidence of long-term symptoms after COVID-19

By Bhavana KunkalikarReviewed by Danielle Ellis, B.Sc.Feb 23 2023

In a recent study posted to the medRxiv* preprint server, researchers assessed the role of poor sleep quality, short sleep duration, and insomnia in predicting long-term coronavirus disease 2019 (COVID-19) symptoms.

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Background

Sleep is essential for human immunity, with poor sleep quality and insufficient sleep length leading to increased susceptibility to viral infections. In addition, recent evidence has associated short sleep duration and sleep disturbances with an elevated risk for inflammatory disorders. This results from the connection between sleep problems and short sleep duration and the persistent generation of pro-inflammatory cytokines along with other circulating biomarkers of inflammation.

Based on these hypotheses, pre-infection sleep disorders may predispose individuals to have long-term effects after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

About the study

In the present study, researchers assessed the relevance of pre-infection sleep duration, quality, and insomnia severity on long-term symptoms following COVID-19.

During the first lockdown period in April 2020, 13,989 people were questioned using web-based questionnaires. In December 2020, almost 2013 respondents were examined longitudinally. In April 2022, the April 2020 survey sample was re-invited to participate in another longitudinal evaluation. Each examination evaluated sleep duration/quality and insomnia severity estimated, utilizing the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI), respectively.

The team obtained demographic as well as other data for each survey wave. In April 2022, respondents were asked whether they had ever tested COVID-19-positive. If so, the participants were asked to respond to a series of ad hoc questions regarding their infection and symptoms.

The team collected data on the month in which swab positivity was detected along with COVID-19 severity in the acute phase of illness, the recovery time to the pre-infection level of daily functioning, and the presence of long-term COVID-19 symptoms noted one and three months after the initial infection.

To determine the relevance of sleep quality, total sleep time (TST), and insomnia severity in assessing long-term symptoms one month after COVID-19 infection, studies were conducted on 713 individuals who reported being infected between April 2020 and February 2022.

A total of 333 persons who reported a positive swab result between February 2020 and December 2021 were analyzed to determine the impact of sleep factors on predicting long-term SARS-CoV-2 symptoms three months after infection.

Results

Most participants were young women within the healthy weight range and held a bachelor's degree or higher. In the acute COVID-19 stage, most responders reported modest COVID-19 severity and returned to their pre-infection level of daily functioning in less than a month.

Worse sleep quality, higher severity of insomnia symptoms, and shorter sleep duration substantially predicted a greater number of long-lasting symptoms one and three months post-SARS-CoV-2 infection. A single-unit increase in ISI and PSQI scores and a one-hour decrease in sleep duration predicted increases of 4.9%, 7.0%, and 11.1% in the number of symptoms observed one month after SARS-CoV-2 infection and 5.4%, 9.1%, and 14.7% increase in the number of symptoms three months after SARS-CoV-2 infection, respectively.

Higher PSQI scores considerably elevated the likelihood of each investigated long-term symptom incidence at one and three months after COVID-19 infection, except for dysfunctions in the senses of taste and smell and cardiovascular difficulties at one month after infection. Additionally, more severe sleeplessness symptoms were remarkably related to increased probabilities of all long-term symptoms assessed except dysfunctions of smell and taste.

A one-hour decrease in sleep duration was related to an increased risk for all long-term symptoms except for asthenia, memory issues, smell/taste dysfunctions, hunger reduction, and cardiovascular abnormalities. In addition, shorter sleep duration was related to an elevated risk for all the reported symptoms three months after infection, except overtiredness, trouble concentrating/paying attention, depression, anxiety, and dysfunctions of smell and taste.

In April 2020, lower sleep quality, higher insomnia severity, and shorter sleep duration predicted longer recovery times to return to pre-infection levels of daily functioning after COVID-19. Prospectively, a one-unit rise in ISI and PSQI scores and a one-hour decrease in sleep duration were related with greater probabilities of recovery over four weeks by 9.3%, 13.1%, and 14.4%, respectively, and post-twelve weeks by 12.0%, 21.3%, and 20.0%, respectively.

Conclusion

The study findings revealed that pre-existing sleep disorders and poor sleep length are connected with subsequent risk of long-term COVID-19 symptoms after infection. The researchers believe that the study could have large-scale ramifications considering the sleep-loss epidemic in the current world culture, the high incidence of insomnia disorder, and occasional insomnia symptoms. Future research is required to evaluate whether interventions focused on improving sleep quality and quantity could ameliorate the long-term effects of COVID-19.

*Important notice: medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.