Pathophysiological Mechanisms in Long COVID: A Mixed Method Systematic Review

INTRODUCTION

Long COVID (LC) is a global public health crisis affecting more than 70 million people. There is emerging evidence of different pathophysiological mechanisms driving the wide array of symptoms in LC. Understanding the relationships between mechanisms and symptoms helps in guiding clinical management and identifying potential treatment targets.

METHODS

This was a mixed-methods systematic review with two stages: Stage one (Review 1) included only existing systematic reviews (meta-review) and Stage two (Review 2) was a review of all primary studies. The search strategy involved Medline, Embase, Emcare, and CINAHL databases to identify studies that described symptoms and pathophysiological mechanisms with statistical analysis and/or discussion of plausible causal relationships between mechanisms and symptoms. Only studies that included a control arm for comparison were included. Studies were assessed for quality using the National Heart, Lung, and Blood Institute quality assessment tools.

RESULTS

19 systematic reviews were included in Review 1 and 46 primary studies in Review 2. Overall, the quality of reporting across the studies included in this second review was moderate to poor. The pathophysiological mechanisms with strong evidence were immune system dysregulation, cerebral hypoperfusion, and impaired gas transfer in the lungs. Other mechanisms with moderate to weak evidence were endothelial damage and hypercoagulation, mast cell activation, and auto-immunity to vascular receptors.

CONCLUSIONS

LC is a complex condition affecting multiple organs with diverse clinical presentations (or traits) underpinned by multiple pathophysiological mechanisms. A 'treatable trait' approach may help identify certain groups and target specific interventions. Future research must include understanding the response to intervention based on these mechanism-based traits.

Effectiveness of Internet-Based Group Supportive Psychotherapy on Psychic and Somatic Symptoms, Neutrophil-Lymphocyte Ratio, and Heart Rate Variability in Post COVID-19 Syndrome Patients

BACKGROUND

COVID-19 can have serious long term health consequences, which is called Post-COVID-19 Syndrome (PCS). Currently, the available evidence and understanding of PCS management is limited. Because one of the symptoms of PCS is associated to psychological symptoms, psychotherapy is believed to have a role in the management of PCS. This study aimed to identify the effectiveness of supportive psychotherapy in PCS patients at Cipto Mangunkusumo National General Hospital.

METHODS

This study was a single blind randomized clinical trial using a pre-and post-test with control group study design. Participants were randomly divided into two groups: a psychotherapy group with 40 participants and an education group with 37 participants. Each group was given internet-based psychotherapy or education three times a week in a form of group consisting of 6-8 participants. Symptom Checklist-90 questionnaire was used to evaluate somatic and psychological symptoms. Heart rate variability and neutrophil lymphocyte ratio were also investigated. Data analysis was performed using the independent T test.

RESULTS

An improvement in the SCL-90 score was found to be 17.51 (SD 30.52) in the psychotherapy group and 19.79 (SD 35.10) in the education group, although there was no significant difference between the two groups (p = 0.771). There was no significant difference between the two groups in decreasing NLR (p = 0.178) and improving HRV (p = 0.560).

CONCLUSION

Both internet-based group supportive psychotherapy and education improved psychological and somatic symptoms in PCS patients, although there was no significant difference between the two groups. There was no significant difference between the two groups in decreasing NLR and improving HRV. Suggestions for further research regarding adding frequency of internet-based group psychotherapy in PCS patients and held in the morning to achieve more optimal results.

Classification of Long COVID from General Practitioner Diagnosis Text

Major challenges exist in identifying Long COVID patients from diagnosis texts recorded by general practitioners. A classification framework is proposed that can be used to identify Long COVID patients given these unstructured diagnostic texts. This framework can be leveraged to provide a general understanding of the risk factors, management strategies, and outcomes associated with Long COVID in Australia.

A scoping review of persistent symptoms after COVID infection at different follow-up periods

The clinical entity termed as long COVID has gained importance in the recent past. As this phenomenon is still evolving, it is important to document the magnitude of the syndrome during different time periods. This scoping review attempts to synthesize evidence generated from longitudinal studies which have follow-up periods beyond 3 months, up to 12 months. The review also documents the reported prevalence of long COVID for the different regions of the World Health Organization. Longitudinal studies published till March 2022 were systematically searched on PubMed, Google Scholar, and medRxiv. Among the identified 594 studies, 48 were included in this review. Data from selected studies were synthesized. The overall pooled prevalence of long COVID was 49% (40%-58%). The pooled estimates after 3 months, 4-6 months, 7-9 months, and 10-12 months were 44% (32%-57%), 50% (43%-57%), 49% (37%-62%), and 54% (46%-62%), respectively. Eastern Mediterranean Region (EMR) had the highest pooled prevalence of 63% (34%-92%] and the South East Asian Region (SEAR) had the least pooled estimate of 15% (10%-21%). The study brings out the high prevalence of long COVID even after 12 months of follow-up. It also shows the regional differences in the reported prevalence of the syndrome. This review highlights the need for well-planned follow-up studies, especially in developing nations to understand the magnitude and the pattern of long COVID-related symptoms as they emerge.

The Adaptive Force as a Potential Biomechanical Parameter in the Recovery Process of Patients with Long COVID

Long COVID patients show symptoms, such as fatigue, muscle weakness and pain. Adequate diagnostics are still lacking. Investigating muscle function might be a beneficial approach. The holding capacity (maximal isometric Adaptive Force; AFiso_max) was previously suggested to be especially sensitive for impairments. This longitudinal, non-clinical study aimed to investigate the AF in long COVID patients and their recovery process. AF parameters of elbow and hip flexors were assessed in 17 patients at three time points (pre: long COVID state, post: immediately after first treatment, end: recovery) by an objectified manual muscle test. The tester applied an increasing force on the limb of the patient, who had to resist isometrically for as long as possible. The intensity of 13 common symptoms were queried. At pre, patients started to lengthen their muscles at ~50% of the maximal AF (AF_max), which was then reached during eccentric motion, indicating unstable adaptation. At post and end, AFiso_max increased significantly to ~99% and 100% of AF_max, respectively, reflecting stable adaptation. AF_max was statistically similar for all three time points. Symptom intensity decreased significantly from pre to end. The findings revealed a substantially impaired maximal holding capacity in long COVID patients, which returned to normal function with substantial health improvement. AFiso_max might be a suitable sensitive functional parameter to assess long COVID patients and to support therapy process.

Post-acute sequelae of SARS-CoV-2 (PASC) syndrome presenting as postural orthostatic tachycardia syndrome (POTS)

The novel SARS-CoV-2 emerged in 2019, and the global COVID-19 pandemic continues into 2022. It has been known that a subset of patients develops chronic, debilitating symptoms after otherwise complete recovery from acute infection of COVID-19. Multiple terms have been used to describe this constellation of symptoms, including long COVID, long-haul COVID, and post-acute sequelae of SARS-CoV-2 syndrome (PASC). PASC is broadly defined as a wide range of new, returning, or ongoing symptoms at least four weeks after infection. Those patients are often seen in emergency departments after acute COVID- 19 infection, but their symptoms are not adequately managed because the underlying pathophysiology of PASC is not well understood. Among patients with PASC, postural orthostatic tachycardic syndrome (POTS) has been increasingly recognized. POTS is one of the most common forms of autonomic dysfunction and defined by a sustained orthostatic tachycardia during active standing or head-up tilt test in the absence of orthostatic hypotension or other cardiopulmonary diseases. Because POTS is a treatable condition, it is important to recognize POTS among PASC patients. Herein, we reviewed the current literature on POTS and dysautonomia in PASC in order to better understand the overlap and distinction between these pathologies.

Post COVID-19 syndrome. Severity and evolution in 4673 health care workers

BACKGROUND

The evolution of post COVID syndrome has been variable and we lack information on its impact on healthcare professionals, particularly in Latin America.

METHODS

We conducted a survey through a social network in health professionals on post COVID-19 syndrome cases confirmed with PCR. In a web-based questionnaire, we asked about 21 symptoms, their severity, duration, degree of activity impairment and return to work.

RESULTS

4673 health professionals from 21 countries responded, mean age of 47.8 years, 64.2% women. The initial course was asymptomatic in 9.1%, mild symptoms 36.8%, moderate symptoms without hospitalization 40.8% or with hospitalization 11.7%, and severe symptoms with respiratory assistance 1.6%. The most prevalent symptoms were fatigue (67%), insomnia (44.2%), anxiety (42.3%), myalgia (41.9%) and anosmia (41.2%). Considering only severe symptoms (grades 3-4 on a subjective index from 1 to 4), the most prevalent were slowness (36.3%), impaired concentration (33.1%), anosmia (20.4%), fatigue (19.1%), impaired memory (18.1%) and dyspnea (15.9%). Prevalence dropped by half in the first 5 five months, but in many cases, it lasted for more than a year. In the multivariate analysis, symptoms tended to be grouped into clusters (cognitive, neuropsychiatric, cardiorespiratory, digestive, others). The need to change the work area was 16% and lack of return to work 7.8%, related to older age, number of symptoms and severity of the initial course.

CONCLUSION

In conclusion, in many cases the persistence of post-COVID symptoms can be prolonged and have an occupational impact on healthcare professionals, requiring the adoption of specific policies to reduce harm.

Pattern of Post COVID Fatigue in Elderly Patients

The incidence of Long COVID (LC) increases with age but then drops sharply in over 70-year-olds. The prevailing explanation is that different biases in data collection such as reluctance to report symptoms or attributing them to comorbidities may explain this pattern in this age group. Our local data suggested a similar pattern confirming the rarity of LC symptoms especially fatigue in the over 70s. Our data have also showed a different phenotype of post COVID fatigue which is not commonly associated with post exertional symptoms bringing into question the suggestion that bias in collecting data is the main cause. We explore several immunological, metabolic and epigenetic factors associated with aging that may explain such phenomenon.

Use of platelet-rich plasma for COVID-19-related olfactory loss: a randomized controlled trial

INTRODUCTION

The current study evaluated the use of platelet-rich plasma (PRP), an autologous blood product with supraphysiologic concentrations of growth factors, in the treatment of prolonged coronavirus disease 2019 (COVID-19)-related smell loss.

METHODS

This multi-institutional, randomized controlled trial recruited patients with COVID-19 who had objectively measured smell loss (University of Pennsylvania Smell Identification Test [UPSIT] ≤ 33) between 6 and 12 months. Patients were randomized to three intranasal injections of either PRP or sterile saline into their olfactory clefts. The primary outcome measure was change in Sniffin' Sticks score (threshold, discrimination, and identification [TDI]) from baseline. The secondary end point measures included responder rate (achievement of a clinically significant improvement, ≥5.5 points TDI), change in individual TDI olfaction scores, and change in subjective olfaction via a visual analog scale.

RESULTS

A total of 35 patients were recruited and 26 completed the study. PRP treatment resulted in a 3.67-point (95% CI: 0.05-7.29, p = 0.047) greater improvement in olfaction compared with the placebo group at 3 months and a higher response rate (57.1% vs 8.3%, odds ratio 12.5 [95% exact bootstrap confidence interval, 2.2-116.7]). There was a greater improvement in smell discrimination following PRP treatment compared with placebo but no difference in smell identification or threshold. There was no difference in subjective scores between PRP and placebo. No adverse effects were reported.

CONCLUSION

Olfactory function following COVID-19 can improve spontaneously after 6 months and can improve to a greater extent with PRP injection. These data build on the promise of PRP to be a safe potential treatment option for patients with COVID-19-related smell loss, and larger-powered studies will help further assess its efficacy.

PROMIS Scales for Assessment of Persistent Post-COVID Symptoms: A Cross Sectional Study

Objective

Persistent post-COVID symptoms are estimated to occur in up to 10% of patients who have had COVID-19. These lingering symptoms may persist for weeks to months after resolution of the acute illness. This study aimed to add insight into our understanding of certain post-acute conditions and clinical findings. The primary purpose was to determine the persistent post COVID impairments prevalence and characteristics by collecting post COVID illness data utilizing Patient-Reported Outcomes Measurement Information System (PROMIS^®). The resulting measures were used to assess surveyed patients physical, mental, and social health status.

Methods

A cross-sectional study and 6-months Mayo Clinic COVID recovered registry data were used to evaluate continuing symptoms severity among the 817 positive tested patients surveyed between March and September 2020. The resulting PROMIS^® data set was used to analyze patients post 30 days health status. The e-mailed questionnaires focused on fatigue, sleep, ability to participate in social roles, physical function, and pain.

Results

The large sample size (n = 817) represented post hospitalized and other managed outpatients. Persistent post COVID impairments prevalence and characteristics were determined to be demographically young (44 years), white (87%), and female (61%). Dysfunction as measured by the PROMIS^® scales in patients recovered from acute COVID-19 was reported as significant in the following domains: ability to participate in social roles (43.2%), pain (17.8%), and fatigue (16.2%).

Conclusion

Patient response on the PROMIS^® scales was similar to that seen in multiple other studies which used patient reported symptoms. As a result of this experience, we recommend utilizing standardized scales such as the PROMIS^® to obtain comparable data across the patients’ clinical course and define the disease trajectory. This would further allow for effective comparison of data across studies to better define the disease process, risk factors, and assess the impact of future treatments.