Clinical Characteristics of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Diagnosed in Patients with Long COVID

Clinical and endocrine features of orthostatic intolerance detected in patients with long COVID

Orthostatic intolerance (OI) is a key symptom of long COVID; however, the pathophysiology remains unknown. Among 688 long COVID patients who visited our clinic during the period from February 2021 to April 2023, 86 patients who were suspected of having OI and who underwent an active standing test (ST) were investigated to elucidate the clinical characteristics of OI in patients with long COVID. Of the 86 patients, 33 patients (38%) were ST-positive. Nausea and tachycardia in daily life were frequent complaints in the ST-positive group. The increase in heart rate (HR) during the ST was significantly greater during a 10-min period after standing in the ST-positive group (+ 30 bpm) than in the ST-negative group (+ 16 bpm). The initial increase in diastolic blood pressure (DBP) just after standing was significantly greater in the ST-positive group (+ 14 mmHg) than in the ST-negative group (+ 9 mmHg). Serum cortisol levels in the ST-positive patients aged over 20 years were higher and growth hormone levels in the patients under 20 years of age were lower than those in the ST-negative group. Autonomous nervous symptoms, transient DBP rise with increasing HR after standing, and endocrine dysfunctions are helpful for detecting OI related to long COVID.

Illness presentation and quality of life in myalgic encephalomyelitis/chronic fatigue syndrome and post COVID-19 condition: a pilot Australian cross-sectional study

PURPOSE

Post COVID-19 Condition (PCC), being persistent COVID-19 symptoms, is reminiscent of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-a chronic multi-systemic illness characterised by neurocognitive, autonomic, endocrinological and immunological disturbances. This novel cross-sectional investigation aims to: (1) compare symptoms among people with ME/CFS (pwME/CFS) and people with PCC (pwPCC) to inform developing PCC diagnostic criteria; and (2) compare health outcomes between patients and people without acute or chronic illness (controls) to highlight the illness burdens of ME/CFS and PCC.

METHODS

Sociodemographic and health outcome data were collected from n = 61 pwME/CFS, n = 31 pwPCC and n = 54 controls via validated, self-administered questionnaires, including the 36-Item Short-Form Health Survey version 2 (SF-36v2) and World Health Organization Disability Assessment Schedule version 2.0 (WHODAS 2.0). PwME/CFS and pwPCC also provided self-reported severity and frequency of symptoms derived from the Canadian and International Consensus Criteria for ME/CFS and the World Health Organization case definition for PCC.

RESULTS

Both illness cohorts similarly experienced key ME/CFS symptoms. Few differences in symptoms were observed, with memory disturbances, muscle weakness, lymphadenopathy and nausea more prevalent, light-headedness more severe, unrefreshed sleep more frequent, and heart palpitations less frequent among pwME/CFS (all p < 0.05). The ME/CFS and PCC participants' SF-36v2 or WHODAS 2.0 scores were comparable (all p > 0.05); however, both cohorts returned significantly lower scores in all SF-36v2 and WHODAS 2.0 domains when compared with controls (all p < 0.001).

CONCLUSION

This Australian-first investigation demonstrates the congruent and debilitating nature of ME/CFS and PCC, thereby emphasising the need for multidisciplinary care to maximise patient health outcomes.

Exploring the Pathophysiology of Long COVID: The Central Role of Low-Grade Inflammation and Multisystem Involvement

Long COVID (LC), also referred to as Post COVID-19 Condition, Post-Acute Sequelae of SARS-CoV-2 Infection (PASC), and other terms, represents a complex multisystem disease persisting after the acute phase of COVID-19. Characterized by a myriad of symptoms across different organ systems, LC presents significant diagnostic and management challenges. Central to the disorder is the role of low-grade inflammation, a non-classical inflammatory response that contributes to the chronicity and diversity of symptoms observed. This review explores the pathophysiological underpinnings of LC, emphasizing the importance of low-grade inflammation as a core component. By delineating the pathogenetic relationships and clinical manifestations of LC, this article highlights the necessity for an integrated approach that employs both personalized medicine and standardized protocols aimed at mitigating long-term consequences. The insights gained not only enhance our understanding of LC but also inform the development of therapeutic strategies that could be applicable to other chronic conditions with similar pathophysiological features.

The molecular fingerprint of neuroinflammation in COVID-19: A comprehensive discussion on molecular mechanisms of neuroinflammation due to SARS-COV2 antigens

BACKGROUND AND OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 attacks the neural system directly and indirectly via various systems, such as the nasal cavity, olfactory system, and facial nerves. Considering the high energy requirement, lack of antioxidant defenses, and high amounts of metal ions in the brain, oxidative damage is very harmful to the brain. Various neuropathic pain conditions, neurological disorders, and neuropsychiatric complications were reported in Coronavirus disease 2019, prolonged Coronavirus disease 2019, and after Coronavirus disease 2019 immunization. This manuscript offers a distinctive outlook on the interconnectedness between neurology and neuropsychiatry through its meticulous analysis of complications.

DISCUSSION

After recovering from Coronavirus disease 2019, approximately half of the patients reported developing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Long Coronavirus disease 2019 imaging reports illustrated the hypometabolism in various parts of the brain, such as olfactory bulbs, limbic/paralimbic domains, the brainstem, and the cerebellum. Ninety imaging and neuropathological studies of Coronavirus disease 2019 have shown evidence of white matter, brainstem, frontotemporal, and oculofrontal lesions. Emotional functions, such as pleasant, long/short-term memory, movement, cognition and cognition in decision-making are controlled by these regions. The neuroinflammation and the mechanisms of defense are well presented in the discussion. The role of microglia activation, Inducible NO synthase, Cyclooxygenases ½, Reactive oxygen species, neurotoxic toxins and pro-inflammatory cytokines, such as Interleukin-1 beta, Interleukin-6 and Tumor Necrosis Factor-alpha are highlighted in neuronal dysfunction and death. Nuclear factor kappa-light-chain-enhancer of activated B cells, Mitogen-activated protein kinase, Activator Protein 1, and Interferon regulatory factors are the main pathways involved in microglia activation in Coronavirus disease 2019 neuroinflammation.

CONCLUSION

The neurological aspect of Coronavirus disease 2019 should be highlighted. Neurological, psychological, and behavioral aspects of Coronavirus disease 2019, prolonged Coronavirus disease 2019, and Coronavirus disease 2019 vaccines can be the upcoming issues. We need a global awareness where this aspect of the disease should be more considered in health research.

Occult endocrine disorders newly diagnosed in patients with post-COVID-19 symptoms

Determination of long COVID requires ruling out alternative diagnoses, but there has been no report on the features of alternative diagnoses. This study was a single-center retrospective study of outpatients who visited our clinic between February 2021 and June 2023 that was carried out to determine the characteristics of alternative diagnoses in patients with post-COVID-19 symptoms. In a total of 731 patients, 50 patients (6.8%) were newly diagnosed with 52 diseases requiring medical intervention, and 16 (32%) of those 50 patients (2.2% of the total) were considered to have priority for treatment of the newly diagnosed disorders over long COVID treatment. The proportion of patients with a new diagnosis increased with advance of age, with 15.7% of the patients aged 60 years or older having a new diagnosis. Endocrine and metabolic diseases and hematological and respiratory diseases were the most common, being detected in eight patients (16%) each. Although 35 of the 52 diseases (67%) were related to their symptoms, endocrine and metabolic diseases were the least associated with specific symptoms. Other disorders that require attention were found especially in elderly patients with symptomatic long COVID. Thus, appropriate assessment and differentiation from alternative diagnoses are necessary for managing long COVID.

Relevance of complement immunity with brain fog in patients with long COVID

INTRODUCTION

This study aimed to elucidate the prevalence and clinical characteristics of patients with long COVID (coronavirus disease 2019), especially focusing on 50% hemolytic complement activity (CH50).

METHODS

This retrospective observational study focused on patients who visited Okayama University Hospital (Japan) for the treatment of long COVID between February 2021 and March 2023. CH50 levels were measured using liposome immunometric assay (Autokit CH50 Assay, FUJIFILM Wako Pure Chemical Corporation, Japan); high CH50 was defined as ≥59 U/mL. Univariate analyses assessed differences in the clinical background, long COVID symptoms, inflammatory markers, and clinical scores of patients with normal and high CH50. Logistic regression model investigated the association between high CH50 levels and these factors.

RESULTS

Of 659 patients who visited our hospital, 478 patients were included. Of these, 284 (59.4%) patients had high CH50 levels. Poor concentration was significantly more frequent in the high CH50 group (7.2% vs. 13.7%), whereas no differences were observed in other subjective symptoms (fatigue, headache, insomnia, dyspnea, tiredness, and brain fog). Multivariate analysis was performed on factors that could be associated with poor concentration, suggesting a significant relationship to high CH50 levels (adjusted odds ratio [aOR], 2.70; 95% confidence interval [CI], 1.33-5.49). Also, high CH50 was significantly associated with brain fog (aOR, 1.66; 95% CI, 1.04-2.66).

CONCLUSIONS

High CH50 levels were frequently reported in individuals with long COVID, indicating a relationship with brain fog. Future in-depth research should examine the pathological role and causal link between complement immunity and the development of long COVID.

Functional and Morphological Differences of Muscle Mitochondria in Chronic Fatigue Syndrome and Post-COVID Syndrome

Patients suffering from chronic fatigue syndrome (CFS) or post-COVID syndrome (PCS) exhibit a reduced physiological performance capability. Impaired mitochondrial function and morphology may play a pivotal role. Thus, we aimed to measure the muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity and assess mitochondrial morphology in CFS and PCS patients in comparison to healthy controls (HCs). Mitochondrial OXPHOS capacity was measured in permeabilized muscle fibers using high-resolution respirometry. Mitochondrial morphology (subsarcolemmal/intermyofibrillar mitochondrial form/cristae/diameter/circumference/area) and content (number and proportion/cell) were assessed via electron microscopy. Analyses included differences in OXPHOS between HC, CFS, and PCS, whereas comparisons in morphology/content were made for CFS vs. PCS. OXPHOS capacity of complex I, which was reduced in PCS compared to HC. While the subsarcolemmal area, volume/cell, diameter, and perimeter were higher in PCS vs. CFS, no difference was observed for these variables in intermyofibrillar mitochondria. Both the intermyofibrillar and subsarcolemmal cristae integrity was higher in PCS compared to CFS. Both CFS and PCS exhibit increased fatigue and impaired mitochondrial function, but the progressed pathological morphological changes in CFS suggest structural changes due to prolonged inactivity or unknown molecular causes. Instead, the significantly lower complex I activity in PCS suggests probably direct virus-induced alterations.

Drawing the Line Between Postacute Sequelae of COVID-19 and Functional Neurologic Disorders: A Daunting Clinical Overlap or Irrelevant Conundrum?

ABSTRACT

Coronavirus disease 2019 (COVID-19) is an acute infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in its multiple variants that classically presents with cough, fatigue, fever, headache, myalgias, and diarrhea. As vaccination becomes widely available and infection rates facilitate herd immunity across the globe, more attention has been given to long-term symptoms that may persist after the index infection, which include impairments in concentration, executive dysfunction, sensory disturbances, depression, anxiety, fatigue, and cough, among other symptoms classified under the umbrella term of postacute sequelae of SARS-CoV-2 infection (PASC).Functional neurologic disorder (FND), also known as conversion disorder and functional neurologic symptom disorder, refers to the presence of one or more symptoms of altered voluntary motor or sensory function that are incompatible with and not better explained by a known neurological or medical condition that causes significant distress and functional impairment. Although the diagnosis of FND may not require the identification of an underlying psychological stressor, being diagnosed with an FND can worsen stigma and shift attention and resources away from other medical concerns that should be concomitantly addressed.This review summarizes the literature on the overlapping nature and discrimination of PASC from FND in COVID-19 survivors. Based on this, we develop a treatment framework that targets unique domains of these complex overlapping presentations, following a multidisciplinary approach with an individualized treatment plan inclusive of physical and psychological interventions focused on functional rehabilitation.

Immunoadsorption to treat patients with severe post-COVID syndrome

INTRODUCTION

Following SARS-CoV-2-infection up to 21% of patients will develop post-COVID-syndrome. Autoantibodies (AAbs) targeting neuronal-ß-adrenergic and muscarinic receptors may provide crucial contributions to the pathophysiology of this condition. Immunoadsorption (IA) has been identified as an effective means of removing AAbs and has resulted in clinical improvements of other autoantibody-associated diseases.

METHODS

We determined AAb-levels (anti-ß1/ß2 and anti-M3/M4 receptor) in 178 patients diagnosed with post-COVID-syndrome and described the clinical courses of two patients with elevated AAb-levels that underwent IA-treatment.

RESULTS

AAbs were detected in 57% (101/178) of patients diagnosed with post-COVID-syndrome. Substantial reductions in AAb-levels and clinical remission were achieved in one of two patients who was treated with IA. However, this patient relapsed within 6 weeks with a concomitant increase in AAb-levels.

CONCLUSION

Collectively, AAbs may play a pathophysiologic role in post-COVID and their removal provide transient benefits in some patients. However, these findings should be further investigated in randomized-controlled-trials.

Utility of Serum Ferritin for Predicting Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in Patients with Long COVID

OBJECTIVE

The most common symptom of post-acute coronavirus disease 2019 (COVID-19) is fatigue, and it potentially leads to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS); however, a specific prognosticator is lacking. We aimed to elucidate the clinical characteristics of patients who developed ME/CFS after COVID-19.

METHODS

In this retrospective observational study, patients who visited Okayama University Hospital for long COVID between February 2021 and March 2022 were investigated.

RESULTS

Of the 234 patients, 139 (59.4%) had fatigue symptoms. Fifty patients with fatigue symptoms (21.4%) met the criteria for ME/CFS (ME/CFS group), while the other 89 patients did not (non-ME/CFS group); 95 patients had no fatigue complaints (no-fatigue group). Although the patients' backgrounds were not significantly different between the three groups, the ME/CFS group presented the highest scores on the self-rating symptom scales, including the Fatigue Assessment Scale (FAS), EuroQol, and the Self-Rating Depression Scale (SDS). Furthermore, serum ferritin levels, which were correlated with FAS and SDS scores, were significantly higher in the ME/CFS group (193.0 μg/L, interquartile range (IQR): 58.8-353.8) than in the non-ME/CFS group (98.2 μg/L, 40.4-251.5) and no-fatigue group (86.7 μg/L, 37.5-209.0), and a high serum ferritin level was prominent in female patients. Endocrine workup further showed that the ME/CFS group had higher thyrotropin levels but lower growth hormone levels in serum and that insulin-like growth factor-I levels were inversely correlated with ferritin levels (R = -0.328, p < 0.05).

CONCLUSIONS

Serum ferritin level is a possible predictor of the development of ME/CFS related to long COVID, especially in female patients.

Manifestation of Headache Affecting Quality of Life in Long COVID Patients

Objectives: The present study aimed to elucidate the characteristics of long COVID patients with headaches. Methods: A single-center retrospective observational study was performed for long COVID outpatients who visited our hospital from 12 February 2021 to 30 November 2022. Results: A total of 482 long COVID patients, after excluding 6, were divided into two groups: the Headache group of patients with complaints of headache (113 patients: 23.4%) and the remaining Headache-free group. Patients in the Headache group were younger (median age: 37 years) than patients in the Headache-free group (42 years), while the ratio of females (56%) in the Headache group was nearly the same as that in the Headache-free group (54%). The proportion of patients in the Headache group who were infected in the Omicron-dominant phase (61%) was larger than the proportions of patients infected in the Delta (24%) and preceding (15%) phases, and that trend was significantly different from the trend in the Headache-free group. The duration before the first visit for long COVID was shorter in the Headache group (71 days) than in the Headache-free group (84 days). The proportions of patients in the Headache group with comorbid symptoms, including general fatigue (76.1%), insomnia (36.3%), dizziness (16.8%), fever (9.7%), and chest pain (5.3%) were larger than the proportions of patients in the Headache-free group, whereas blood biochemical data were not significantly different between the two groups. Interestingly, patients in the Headache group had significant deteriorations of scores indicating depression and scores for quality of life and general fatigue. In multivariate analysis, headache, insomnia, dizziness, lethargy, and numbness were shown to be involved in the quality of life (QOL) of long COVID patients. Conclusions: The manifestation of headaches related to long COVID was found to have a significant impact on social and psychological activities. Alleviation of headaches should be a priority for the effective treatment of long COVID.

COVID-19, post-acute COVID-19 syndrome (PACS, "long COVID") and post-COVID-19 vaccination syndrome (PCVS, "post-COVIDvac-syndrome"): Similarities and differences

Worldwide there have been over 760 million confirmed coronavirus disease 2019 (COVID-19) cases, and over 13 billion COVID-19 vaccine doses have been administered as of April 2023, according to the World Health Organization. An infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to an acute disease, i.e. COVID-19, but also to a post-acute COVID-19 syndrome (PACS, "long COVID"). Currently, the side effects of COVID-19 vaccines are increasingly being noted and studied. Here, we summarise the currently available indications and discuss our conclusions that (i) these side effects have specific similarities and differences to acute COVID-19 and PACS, that (ii) a new term should be used to refer to these side effects (post-COVID-19 vaccination syndrome, PCVS, colloquially "post-COVIDvac-syndrome"), and that (iii) there is a need to distinguish between acute COVID-19 vaccination syndrome (ACVS) and post-acute COVID-19 vaccination syndrome (PACVS) - in analogy to acute COVID-19 and PACS ("long COVID"). Moreover, we address mixed forms of disease caused by natural SARS-CoV-2 infection and COVID-19 vaccination. We explain why it is important for medical diagnosis, care and research to use the new terms (PCVS, ACVS and PACVS) in order to avoid confusion and misinterpretation of the underlying causes of disease and to enable optimal medical therapy. We do not recommend to use the term "Post-Vac-Syndrome" as it is imprecise. The article also serves to address the current problem of "medical gaslighting" in relation to PACS and PCVS by raising awareness among the medical professionals and supplying appropriate terminology for disease.

Elevated SARS-CoV-2-Specific Antibody Levels in Patients with Post-COVID Syndrome

With the routine use of effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, the number of life-threatening coronavirus disease 2019 (COVID-19) courses have largely been reduced. However, multiple COVID-19 convalescents, even after asymptomatic to moderate disease, suffer from post-COVID syndrome, with relevant limitations in daily life. The pathophysiologic mechanisms of post-COVID syndrome are still elusive, with dysregulation of the immune system suggested as a central mechanism. Here, we assessed COVID-19 post-infectious symptoms (5-6 months after PCR-confirmed acute infection) together with the humoral immune response against SARS-CoV-2 in non-hospitalized COVID-19 convalescents, early (5-6 weeks) and late (5-6 months) after their first positive SARS-CoV-2 PCR result. Convalescents reporting several post-infectious symptoms (>3) showed higher anti-spike and anti-nucleocapsid antibody levels 5-6 weeks after PCR-confirmed infection with the latter remained increased 5-6 months after positive PCR. Likewise, a higher post-infectious symptom score was associated with increased antibody levels. Of note, convalescents displaying neuro-psychiatric symptoms such as restlessness, palpitations, irritability, and headache, as well as general symptoms such as fatigue/reduced power had higher SARS-CoV-2-specific antibody levels compared with asymptomatic cases. The increased humoral immune response in convalescents with post-COVID syndrome might be useful for the detection of individuals with an increased risk for post-COVID syndrome.

Symptomatic Characteristics of Hypozincemia Detected in Long COVID Patients

OBJECTIVES

The aim of this study was to determine the characteristics of hypozincemia in long COVID patients.

METHODS

This study was a single-center retrospective observational study for outpatients who visited the long COVID clinic established in a university hospital during the period from 15 February 2021 to 28 February 2022. Characteristics of patients with a serum zinc concentration lower than 70 μg/dL (10.7 μmol/L) were compared with characteristics of patients with normozincemia.

RESULTS

In a total of 194 patients with long COVID after excluding 32 patients, hypozincemia was detected in 43 patients (22.2%) including 16 male patients (37.2%) and 27 female patients (62.8%). Among various parameters including the background characteristics of the patients and medical histories, the patients with hypozincemia were significantly older than the patients with normozincemia (median age: 50 vs. 39 years). A significant negative correlation was found between serum zinc concentrations and age in male patients (R = -0.39; p < 0.01) but not in female patients. In addition, there was no significant correlation between serum zinc levels and inflammatory markers. General fatigue was the most frequent symptom in both male patients with hypozincemia (9 out of 16: 56.3%) and female patients with hypozincemia (8 out of 27: 29.6%). Patients with severe hypozincemia (serum zinc level lower than 60 μg/dL) had major complaints of dysosmia and dysgeusia, which were more frequent complaints than general fatigue.

CONCLUSIONS

The most frequent symptom in long COVID patients with hypozincemia was general fatigue. Serum zinc levels should be measured in long COVID patients with general fatigue, particularly in male patients.

Trends in Long COVID Symptoms in Japanese Teenage Patients

Background: Since the start of the global pandemic of coronavirus disease 2019 (COVID-19), not only adults but also many children have suffered from it. However, the clinical characteristics of long COVID in children remain unclear. Methods: In this retrospective observational study conducted in a single facility, we reviewed the medical records of all long COVID patients who visited Okayama University Hospital from February 2021 to October 2022, and we compared the clinical characteristics of long COVID in teenagers (11 to 18 years of age) with those in adults. Results: Data for 452 long COVID patients including 54 teenagers (11.9%) were analyzed. Fatigue was the most frequent symptom in teenagers (55.6% of the patients) and also in adults. On the other hand, the percentage of teenagers who complained of headache, which was the second most frequent complaint, was significantly higher than the percentage of adults (35.2% vs. 21.9%, p < 0.05). A comparison of the frequencies of symptoms depending on the viral variant showed that fatigue and headache were predominant symptoms in the Omicron variant phase. Of the 50 teenagers who were enrolled in schools, 28 (56.0%) could not attend school due to long COVID symptoms. The most common symptoms as reasons for absence from school were fatigue (85.7% of the patients), headache (42.9%), and insomnia (32.1%). Conclusions: Attention should be paid to the symptoms of fatigue and headache in teenagers with long COVID.

A description of the current status of chronic fatigue syndrome and associated factors among university students in Wuhan, China

Introduction

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a group of chronic conscious fatigue that is not easily relieved by rest and is accompanied by corresponding physiological dysfunction and psychological symptoms. However, due to the insufficient understanding of the pathogenesis of ME/CFS, there is currently a lack of effective treatment methods. In addition, there are few surveys on the current status of ME/CFS in the central region of China, and the data on ME/CFS among university students in the central region are lacking. This group conducted a survey on university students in Wuhan, Hubei Province in 2022 to collect and analyze the current status of ME/CFS among university students in central China for the first time, aiming to understand the current development of ME/CFS among university students, investigate the influencing factors of its prevalence, fill the data gaps, and provide a reliable basis for developing interventions for chronic fatigue syndrome among university students.

Methods

A cross-sectional study was conducted among university students in a university in Hubei province. Data were collected via online questionnaire surveys. The contents included demographic characteristics, lifestyles, disease history, depression, anxiety, sleep, ME/CFS and other associated factors. SAS 9.4 statistical software was used to analyze and estimate the effect of associated factors on ME/CFS.

Results

A total of 1826 subjects were included in the final analysis. The results showed that the prevalence of ME/CFS in university students was 6.25%. Univariate analysis showed that exercise, alcohol consumption, study, overnights, diet, anxiety, depression, and sleep quality were associated with ME/CFS (P < 0.05). Multivariate analysis showed that overnights, overeating, anxiety, and sleep quality were independent risk factors, while learning was a protective factor.

Conclusion

College students should pay enough attention to ME/CFS, improve their understanding of ME/CFS, and improve people's ability to understand ME/CFS.

Characteristics of Sleep Disturbance in Patients with Long COVID: A Retrospective Observational Study in Japan

OBJECTIVES

The objective of this study was to determine the clinical and endocrinological features of sleep disturbance in patients with long COVID.

METHODS

This study was a single-center retrospective observational study for patients who visited the COVID-19 aftercare outpatient clinic (CAC) established in Okayama University Hospital in Japan during the period from 15 February 2021 to 29 July 2022. The long COVID patients were divided into two groups based on the presence or absence of sleep disturbance, and the clinical and laboratory characteristics of the patients were analyzed.

RESULTS

Out of 363 patients with long COVID, after excluding 6 patients, 60 patients (16.5%) (55% males, median age of 38 years) complaining of sleep disturbance were compared with 303 patients (83.5%) (43% males, median age of 40 years) without sleep-related symptoms. Although there were no significant differences in clinical backgrounds and severities of COVID-19 between the two groups by the multivariate analysis, the percentage of long COVID patients with sleep disturbance was significantly increased among patients infected in the Omicron-dominant phase. In addition, the prevalence rate of sleep disturbance in patients when infected in the Omicron phase (24.8%) was two-times higher than that in patients infected in the Delta phase (12.8%). Of note, the percentages of patients with sleep disturbance who also complained of general fatigue, headache, concentration loss, anxiety, low-grade fever, and brain fog symptoms were higher than the percentages of patients without sleep disturbance who had the same complaints. Among the types of sleep disturbance, the percentage of patients who complained of loss of sleep induction (75%) was much higher than the percentage of patients with early-awakening sleep disturbance (6.7%), and many of the patients with mid-awakening types of insomnia had brain fog symptoms. Endocrine examinations revealed that long COVID patients with sleep disturbance had significantly higher levels of plasma adrenocorticotropin and lower levels of serum growth hormone, suggesting the presence of hypothalamic-pituitary stress.

CONCLUSION

The prevalence of sleep disturbance has been increasing in long COVID patients infected in the Omicron phase with a certain clinical and endocrine trend.

Transitional Changes in Fatigue-Related Symptoms Due to Long COVID: A Single-Center Retrospective Observational Study in Japan

Background and Objectives: Changes in post COVID-19 condition (PCC) characteristics caused by viral variants have yet to be clarified. We aimed to characterize the differences between clinical backgrounds and manifestations in long COVID patients who were infected with the Delta variant and those who were infected with the Omicron variants. Materials and Methods: This study was a single-center retrospective observational study for patients who visited our COVID-19 aftercare outpatient clinic (CAC) established in Okayama University Hospital (Japan) during the period from 15 February 2021 to 15 July 2022. We classified the onset of COVID-19 in the patients into three groups, the preceding, Delta-dominant, and Omicron-dominant periods, based on the prevalent periods of the variants in our prefecture. Results: In a total of 353 patients, after excluding 8 patients, 110, 130, and 113 patients were classified into the preceding, Delta-dominant, and Omicron-dominant periods, respectively. Patients infected in the Omicron-dominant period had significantly fewer hospitalizations, milder illnesses, more vaccinations and earlier visit to the CAC than did patients infected in the Delta-dominant period. Patients infected in the Omicron-dominant period had significantly lower frequencies of dysosmia (12% vs. 45%, ** p < 0.01), dysgeusia (14% vs. 40%, ** p < 0.01) and hair loss (7% vs. 28%, ** p < 0.01) but had higher frequencies of fatigue (65% vs. 50%, * p < 0.05), insomnia (26% vs. 13%, * p < 0.05) and cough (20% vs. 7%, ** p < 0.01) than did patients infected in the Delta-dominant period. Conclusions: The transitional changes in long COVID symptoms caused by the two variants were characterized.