The presence of fatigue is a recognised post-COVID-19 symptom but its prevalence remains largely unknown.
The fact that patients who recover from an acute COVID-19 infection will, in some cases, continue to experience a range of symptoms, termed “long COVID”, is now widely accepted. In fact, in the UK, services to help support those with long COVID have already been established. However, there is still a lack of clarity over the prevalence of long covid symptoms and such knowledge is essential for optimising the health outcomes of such individuals. In an attempt to provide some clarity on this, a team from the Faculty of Medicine, Department of Psychiatry, University of Ottawa, Canada, undertook a systematic review and meta-analysis, with the specific aim of identifying the prevalence of fatigue as a symptom of long covid from both cross-sectional and longitudinal studies. In addition, the team sought to examine potential associations of fatigue with initial COVID-19 illness severity, patient populations (e.g., hospitalised vs community) and the impact of co-morbidities. Studies were included where fatigue was assessed through either self-reporting, clinical interview or a fatigue specific scale.
A literature search yielded 31 published studies and 8 preprints, undertaken in 18 countries and with a total sample size of 8825 recovered participants. While many of the studies included hospitalised patients, interestingly, two of the studies recruited via social media or a smartphone app. The duration of follow-up varied from 30 days post-infection through to 180 days (6 months). A further observation was how the prevalence of fatigue varied depending on whether it was self-reported or determined using a validated scale. For example, in studies following up patients for at least 30 days, the prevalence of self-reported fatigue was 51.7% compared to 32% when a validated scale had been used. Only two studies reported fatigue after 6 months and again this varied from 62.7% (when self-reported) to 35.6% (when a validated scale was used). When compared to healthy controls, the risk of fatigue among those with COVID-19 was found to be nearly four times higher when assessed between 76–97 days after the acute infection (relative risk, RR = 3.68, 95% CI 2.5 – 5.4, p < 0.001).
In a summary of their findings, the authors discussed how between 30 and 60% of inpatient and outpatients reported fatigue, although this was as high as 90% based on self-reporting via social media. They also noted that the presence of fatigue did not appear to be related to initial disease severity or patient age. A recognised limitation of the analysis was the high level of heterogeneity in study design, follow-up and methods of assessment. Nevertheless, it was clear that fatigue was indeed a post-infection symptom and the authors concluded by calling for a more objective assessment of fatigue and a standardised method of follow-up.
Rao S et al. Fatigue symptoms associated with COVID-19 in convalescent or recovered COVID-19 patients: a systematic review and meta-analysis. MedRxiv 2021