ABSTRACT
BackgroundThe clinical sequelae (Long Covid) of acute Covid-19 are recognised globally, yet the risk of developing them is unknown. MethodsA living systematic review (second version). Bibliographical records from the C19 Living Map Long Covid segment (22nd February 2022), Medline, CINAHL, Global Health, WHO Covid-19 database, LitCOVID, and Google Scholar (18th November 2021). We included studies with at least 100 people at 12 weeks or more post-Covid-19 onset and with a control group without confirmed Covid-19. Risk of bias was assessed using the Newcastle-Ottawa scale. Symptoms are aligned with the Post Covid-19 Condition Core Outcome Set. We present descriptive statistics and use meta-analysis to estimate the relative risk of experiencing Long Covid. ResultsTwenty-eight studies were included: 20 cohort, five case-controls, three cross-sectional. Studies reported on 242,715 people with Covid-19 (55.6% female) and 276,317 controls (55.7% female) in 16 countries. Most were of moderate quality (71%). Only two were set in low-middle-income countries and few included children (18%). The longest mean follow-up time was 419.8 (standard deviation 49.4) days post-diagnosis. The relative risk (RR) of experiencing persistent or new symptoms in cases compared with controls was 1.53 (95% CI: 1.50 to 1.56). The core outcomes with the highest increased risk were cardiovascular (RR 2.53 95% CI: 2.16 to 2.96), cognitive (RR 1.99; 95% CI: 1.82 to 2.17), and physical functioning (RR 1.85; 95% CI: 1.75 to 1.96). ConclusionSARS-CoV-2 infection is associated with a higher risk of new or persistent symptoms when compared with controls that can last over a year following acute Covid-19. There is still a lack of robust studies set in lower resourced settings and current studies have high heterogeneity and potential misclassifications of cases and controls. Future research should explore the role of vaccination and different variants on the risk of developing Long Covid. Systematic review registrationThe protocol was prospectively registered on the PROSPERO database (CRD42020211131). O_TEXTBOXO_TEXTBOXNOSection 1:C_TEXTBOXNO What is already known?O_LIPublished evidence indicates a high prevalence of people affected by post-acute SARS-CoV-2 sequelae often referred to as Long Covid; yet these estimates are impacted by heterogeneity in study design and a lack of controlled studies and core outcome sets. C_LIO_LIOur first version of this review, looking at studies till March 2021, identified a breadth of reported symptoms of Long Covid affecting both those who were hospitalised during the acute phase and those managed in the community. We also identified a lack of studies including children and set in low-middle income countries. C_LIO_LIThe most commonly reported symptoms identified were weakness, general malaise, fatigue, concentration difficulties, and breathlessness, suggesting Long Covid is a complex, heterogeneous condition. C_LI O_TEXTBOXNOSection 2:C_TEXTBOXNO What are the new findings?O_LITo address the limitations identified, this first update of our living systematic review provides a comprehensive summary of peer-reviewed published studies with a control group (till 22nd February 2022) on the risk of experiencing Covid-19 sequelae. C_LIO_LIDespite study limitations identifying control groups, our findings suggest that people with a confirmed previous SARS-CoV-2 infection are 1.5 times more likely to experience new or persisting symptoms at 12 or more weeks post-onset when compared to a control group. C_LIO_LIMapped to the new Core Outcome set for Post-Covid-19 Condition, a framework for standardised assessment, our review identifies cardiovascular functioning, cognitive functioning, and physical functioning as the outcomes with highest increased risk for people post-SARS-CoV-2 infection compared to controls. C_LI O_TEXTBOXNOSection 3:C_TEXTBOXNO What do the new findings imply?O_LIOur findings point to a clear association between exposure to SARS-CoV-2 and the risk of developing new or persistent symptoms, for some lasting longer than 12 months after the initial infection. C_LIO_LIControlled studies on Long Covid should focus on improving quality to enable multisite metaanalysis by using standardised research protocols and by evaluating participants with multiple standardised diagnostic tests at various time points to capture transitory and intermittent symptoms and complications. C_LIO_LITo help inform health system planning and rehabilitation to improve outcomes for those affected, Long Covid research should focus on estimating the burden of post-acute SARS-CoV-2 in lower resourced settings, investigating the impact of vaccination and variants on Long Covid, and investigating therapeutic strategies. C_LI C_TEXTBOX
ABSTRACT
BackgroundThe long-term sequalae of COVID-19 remain poorly characterised. In this study, we aimed to assess long-standing symptoms (LS) (symptoms lasting from the time of discharge) in previously hospitalised patients with COVID-19 and assess associated risk factors. MethodsThis is a longitudinal cohort study of adults ([≥]18 years of age) with clinically diagnosed or laboratory-confirmed COVID-19 admitted to Sechenov University Hospital Network in Moscow, Russia. Data were collected from patients discharged between April 8 and July 10, 2020. Participants were interviewed via telephone using Tier 1 ISARIC Long-term Follow-up Study CRF and the WHO CRF for Post COVID conditions. Reported symptoms were further categorised based on the system(s) involved. Additional information on dyspnoea, quality of life and fatigue was collected using validated instruments. Multivariable logistic regressions were performed to investigate risk factors for development of LS categories. FindingsOverall, 2,649 of 4,755 patients discharged from the hospitals were available for the follow-up and included in the study. The median age of the patients was 56 years (IQR, 46-66) and 1,353 (51.1%) were women. The median follow-up time since hospital discharge was 217.5 (200.4-235.5) days. At the time of the follow-up interview 1247 (47.1%) participants reported LS. Fatigue (21.2%, 551/2599), shortness of breath (14.5%, 378/2614) and forgetfulness (9.1%, 237/2597) were the most common LS reported. Chronic fatigue (25%, 658/2593) and respiratory (17.2% 451/2616) were the most common LS categories. with reporting of multi-system involvement (MSI) less common (11.3%; 299). Female sex was associated with LS categories of chronic fatigue with an odds ratio of 1.67 (95% confidence interval 1.39 to 2.02), neurological (2.03, 1.60 to 2.58), mood and behaviour (1.83, 1.41 to 2.40), dermatological (3.26, 2.36 to 4.57), gastrointestinal (2.50, 1.64 to 3.89), sensory (1.73, 2.06 to 2.89) and respiratory (1.31, 1.06 to 1.62). Pre-existing asthma was associated with neurological (1.95, 1.25 to 2.98) and mood and behavioural changes (2.02, 1.24 to 3.18) and chronic pulmonary disease was associated with chronic fatigue (1.68, 1.21 to 2.32). Interpretation6 to 8 months after acute infection episode almost a half of patients experience symptoms lasting since hospital discharge. One in ten individuals experiences MSI. Female sex is the main risk factor for majority of the LS categories. chronic pulmonary disease is associated with a higher risk of chronic fatigue development, and asthma with neurological and mood and behaviour changes. Individuals with LS and MSI should be the main target for future research and intervention strategies. FundingThis study is supported by Russian Fund for Basic Research and UK Embassy in Moscow. The ISARIC work is supported by grants from: the NIHR Health Protection Research Unit (HPRU) in Emerging and Zoonotic Infections at University of Liverpool in partnership with Public Health England (PHE), in collaboration with Liverpool School of Tropical Medicine and the University of Oxford [award 200907], Wellcome Trust and Department for International Development [215091/Z/18/Z], and the Bill and Melinda Gates Foundation [OPP1209135], EU Platform for European Preparedness Against (Re-) emerging Epidemics (PREPARE) [FP7 project 602525] This research was funded in part, by the Wellcome Trust. The views expressed are those of the authors and not necessarily those of the DID, NIHR, Wellcome Trust or PHE. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSEvidence suggests that COVID-19 may result in short- and long-term consequences to health. Most studies do not provide definitive answers due to a combination of short follow-up (2-3 months), small sample size, and use of non-standardised tools. There is a need to study the longer-term health consequences of previously hospitalised patients with COVID-19 infection and to identify risk factors for sequalae. Added value of this studyTo our knowledge, this is the largest cohort study (n=2,649) with the longest follow-up since hospital discharge (6-8 months) of previously hospitalised adult patients. We found that 6-8 months after discharge from the hospital, around a half (47.1%) of patients reported at least one long-standing symptom since discharge. Once categories of symptoms were assessed, chronic fatigue and respiratory problems were the most frequent clusters of long-standing symptoms in our patients. Of those patients having long-term symptoms, a smaller proportion (11.3%) had multisystem involvement, with three or more categories of long-standing symptoms present. Although most patients developed symptoms since discharge, a smaller number of individuals experienced symptom beginning symptom appearing weeks or months after the acute phase. Female sex was a predictor for most of the symptom categories at the time of the follow-up interview, with chronic pulmonary disease associated with chronic fatigue-related symptoms, and asthma with a higher risk of neurological symptoms, mood and behaviour problems. Implications of all the available evidenceThe majority of patients experienced long-lasting symptoms 6 to 8 months after hospital discharge and almost half reported at least one long-standing symptom, with chronic fatigue and respiratory problems being the most frequent. A smaller number reported multisystem impacts with three or more long-standing categories present at follow-up. A higher risk was found for women, for chronic pulmonary disease with chronic fatigue, and neurological symptoms and mood and behaviour problems with asthma. Patterns of the symptom development following COVID-19 should be further investigated in future research.
ABSTRACT
BackgroundWhile it is now apparent clinical sequelae (often called Long Covid) may persist after acute Covid-19, their nature, frequency, and aetiology are poorly characterised. This study aims to regularly synthesise evidence on Long Covid characteristics, to inform clinical management, rehabilitation, and interventional studies to improve long term outcomes. MethodsA living systematic review. Medline, CINAHL (EBSCO), Global Health (Ovid), WHO Global Research Database on Covid-19, LitCOVID, and Google Scholar were searched up to 17th March 2021. Published studies including at least 100 people with confirmed or clinically suspected Covid-19 at 12 weeks or more post-onset were included. Results were analysed using descriptive statistics and meta-analyses to estimate prevalence with 95% confidence intervals (CIs). ResultsThirty-nine studies were included: 32 cohort, six cross-sectional, and one case-control. Most showed high or moderate risk of bias. None were set in low-income countries, limited studies included children. Studies reported on 10,951 people (48% female) in 12 countries. Most followed-up post hospital discharge (78%, 8520/10951). The longest mean follow-up was 221.7 (SD: 10.9) days post Covid-19 onset. An extensive range of symptoms with wide prevalence was reported, most commonly weakness (41%; 95% CI 25% to 59%), malaise (33%; 95% CI 15% to 57%), fatigue (31%; 95% CI 24% to 39%), concentration impairment (26%; 95% CI 21% to 32%), and breathlessness (25%; 95% CI 18% to 34%). Other frequent symptoms included musculoskeletal, neurological, and psychological. 37% (95% CI 18% to 60%) of people reported reduced quality of life. ConclusionLong Covid is a complex condition with heterogeneous symptoms. The nature of the studies precludes a precise case definition or evaluation of risk factors. There is an urgent need for prospective, robust, standardised controlled studies into aetiology, risk factors, and biomarkers to characterise Long Covid in different at-risk populations and settings. Systematic review registrationThe protocol was prospectively registered on the PROSPERO database (CRD42020211131). Section 1: What is already known?O_LIA significant number of people continue to describe ongoing symptoms long after the acute phase of Covid-19, often referred to as Long Covid. C_LIO_LILong Covid is a heterogeneous condition with an uncertain prevalence, for which there is currently no precise case definition. C_LI Section 2: What are the new findings?O_LIThis living systematic review provides a comprehensive summary of peer-reviewed published evidence on persistent symptoms of Covid-19 and will be regularly updated as new evidence emerges. C_LIO_LIThe breadth of reported symptoms suggests a complex, heterogeneous condition affecting both those who were hospitalised and those managed in the community. C_LIO_LIOur review identifies weakness (41%; 95% CI 25% to 59%), general malaise (33%; 95% confidence interval 15% to 57%), fatigue (31%; 95% CI 24% to 39%), concentration impairment (26%; 95% CI 21% to 32%) and breathlessness (25%; 95% CI 18% to 34%) as the most common symptoms. C_LI Section 3: What do the new findings imply?O_LIThe current evidence base of the clinical spectrum of Long Covid is limited, based on heterogenous data, and vulnerable to biases, hence caution should be used when interpreting or generalising the results. C_LIO_LIOur review identifies areas where further Long Covid research is critically needed to help characterise Long Covid in different populations and define its aetiology, risk factors, and biomarkers, as well as the impact on variants of concern and vaccination on long term outcomes. C_LI
