A recently published systematic review of 154 studies covering a total of 252,437 participants and a meta-analysis of 31 studies found that around a third (28.98%) of adults who had previously suffered from COVID-19 experience persistent sleep problems for more than four weeks after surviving the infection.

The Long-term Consequences of the Pandemic

The COVID-19 pandemic has fundamentally changed the world and although it is officially over, it has an ongoing impact on global health. For some, the acute coronavirus or COVID-19 infection can also be followed by a long-term form of the disease known as long-COVID or post-acute COVID-19 syndrome.

A systematic review and meta-analysis published in 2023 by researchers from Taipei Medical University in China aim to determine the prevalence of sleep disorders in adults in the context of long-COVID.

Data Collection and Analysis

By evaluating relevant research papers from various databases (MEDLINE, EMBASE, Scopus and Web of Science; available data up to November 21st, 2022) and taking into account studies with a follow-up period of at least 28 days, 153 articles with 252,437 COVID-19 patients were identified as relevant resources. Among these, 31 studies were used for a detailed analysis.

Outcome, Frequency and Risk Factors

The study confirmed an overall prevalence of sleep disorders after a COVID-19 infection of around 28.98%, indicating an average of one in three adults. People in Europe were most affected, while the lowest rates were recorded in Southeast Asia. Particularly severe, acute COVID-19 disease and female gender were identified as clear risk factors. Thus, women were found to suffer more frequently from sleep disorders as a result of Long-COVID than men. The most frequently reported problems were poor sleep quality, excessive daytime sleepiness, insomnia and sleep apnoea. Another interesting observation made by the researchers was that the estimated frequency of sleeping problems after an acute coronavirus infection was significantly higher, depending on the method used to assess them. In the case of symptom questionnaires, self-reports and personal interviews, the frequency estimate was significantly lower than when using standardised scales such as the Epworth Sleepiness Scale or the Pittsburgh Sleep Quality Index.

The authors emphasise that the mechanisms underlying sleep disorders in Long COVID should be urgently investigated in order to find effective strategies for their treatment.

Dr Monika Haack, head of an ongoing study

"The way Long COVID patients process pain, is that similar to what we see in people with insomnia or bad sleep? There’s really no data out there. This is one of the first studies that will characterise it."

Outlook

It is clear that further research and investigation are needed to better understand the effects of Long COVID on sleep.

In this context, the US National Institutes of Health (NIH) is supporting two smaller studies that will focus on various aspects of Long COVID and sleep. The first study, led by Dr Monika Haack, looks at the interaction between sleep and pain and how it relates to Long COVID. Another study, led by Dr Kristen Knutson and Dr Igor Koralnik, investigates the relationship between sleep, inflammation and cognitive problems such as fatigue and brain fog in people aged 55 and older, exploring the neurological after-effects of COVID-19, known as neuro-PASC.

Both studies emphasise the complexity of sleep disorders in Long COVID and the importance of understanding these problems for the development of effective treatments. That way, the researchers hope to find targeted interventions for the symptoms and ultimately improve the quality of life of patients affected by Long COVID.