Emotional, hyperactivity and inattention problems in adolescents with immunocompromising chronic diseases during the COVID-19 pandemic.

OBJECTIVE: To assess factors associated with emotional changes and Hyperactivity/Inattention (HI) motivated by COVID-19 quarantine in adolescents with immunocompromising diseases. METHODS: A cross-sectional study included 343 adolescents with immunocompromising diseases and 108 healthy adolescents. Online questionnaires were answered including socio-demographic data and self-rated healthcare routine during COVID-19 quarantine and validated surveys: Strengths and Difficulties Questionnaire (SDQ), Pittsburgh Sleep Quality Index (PSQI), Pediatric Quality of Life Inventory 4.0 (PedsQL4.0). RESULTS: The frequencies of abnormal emotional SDQ scores from adolescents with chronic diseases were similar to those of healthy subjects (110/343 [32%] vs. 38/108 [35%], p = 0.548), as well as abnormal hyperactivity/inattention SDQ scores (79/343 [23%] vs. 29/108 [27%], p = 0.417). Logistic regression analysis of independent variables associated with abnormal emotional scores from adolescents with chronic diseases showed: female sex (Odds Ratio [OR = 3.76]; 95% Confidence Interval (95% CI) 2.00‒7.05; p < 0.001), poor sleep quality (OR = 2.05; 95% CI 1.08‒3.88; p = 0.028) and intrafamilial violence during pandemic (OR = 2.17; 95% CI 1.12‒4.19; p = 0.021) as independently associated with abnormal emotional scores, whereas total PedsQL score was inversely associated with abnormal emotional scores (OR = 0.95; 95% CI 0.93‒0.96; p < 0.0001). Logistic regression analysis associated with abnormal HI scores from patients evidenced that total PedsQL score (OR = 0.97; 95% CI 0.95‒0.99; p = 0.010], changes in medical appointments during the pandemic (OR = 0.39; 95% CI 0.19-0.79; p = 0.021), and reliable COVID-19 information (OR = 0.35; 95% CI 0.16‒0.77; p = 0.026) remained inversely associated with abnormal HI scores. CONCLUSION: The present study showed emotional and HI disturbances in adolescents with chronic immunosuppressive diseases during the COVID-19 pandemic. It reinforces the need to promptly implement a longitudinal program to protect the mental health of adolescents with and without chronic illnesses during future pandemics.

Technical performance of a lateral flow immunoassay for detection of anti-SARS-CoV-2 IgG in the outpatient follow-up of non-severe cases and at different times after vaccination: comparison with enzyme and chemiluminescent immunoassays.

This study assessed the technical performance of a rapid lateral flow immunochromatographic assay (LFIA) for the detection of anti-SARS-CoV-2 IgG and compared LFIA results with chemiluminescent immunoassay (CLIA) results and an in-house enzyme immunoassay (EIA). To this end, a total of 216 whole blood or serum samples from three groups were analyzed: the first group was composed of 68 true negative cases corresponding to blood bank donors, healthy young volunteers, and eight pediatric patients diagnosed with other coronavirus infections. The serum samples from these participants were obtained and stored in a pre-COVID-19 period, thus they were not expected to have COVID-19. In the second group of true positive cases, we chose to replace natural cases of COVID-19 by 96 participants who were expected to have produced anti-SARS-CoV-2 IgG antibodies 30-60 days after the vaccine booster dose. The serum samples were collected on the same day that LFIA were tested either by EIA or CLIA. The third study group was composed of 52 participants (12 adults and 40 children) who did or did not have anti-SARS-CoV-2 IgG antibodies due to specific clinical scenarios. The 12 adults had been vaccinated more than seven months before LFIA testing, and the 40 children had non-severe COVID-19 diagnosed using RT-PCR during the acute phase of infection. They were referred for outpatient follow-up and during this period the serum samples were collected and tested by CLIA and LFIA. All tests were performed by the same healthcare operator and there was no variation of LFIA results when tests were performed on finger prick whole blood or serum samples, so that results were grouped for analysis. LFIA's sensitivity in detecting anti-SARS-CoV-2 IgG antibodies was 90%, specificity 97.6%, efficiency 93%, PPV 98.3%, NPV 86.6%, and likelihood ratio for a positive or a negative result were 37.5 and 0.01 respectively. There was a good agreement (Kappa index of 0.677) between LFIA results and serological (EIA or CLIA) results. In conclusion, LFIA analyzed in this study showed a good technical performance and agreement with reference serological assays (EIA or CLIA), therefore it can be recommended for use in the outpatient follow-up of non-severe cases of COVID-19 and to assess anti-SARS-CoV-2 IgG antibody production induced by vaccination and the antibodies decrease over time. However, LFIAs should be confirmed by using reference serological assays whenever possible.

Persistent symptoms and decreased health-related quality of life after symptomatic pediatric COVID-19: A prospective study in a Latin American tertiary hospital.

OBJECTIVES: To prospectively evaluate demographic, anthropometric and health-related quality of life (HRQoL) in pediatric patients with laboratory-confirmed coronavirus disease 2019 (COVID-19). METHODS: This was a longitudinal observational study of surviving pediatric post-COVID-19 patients (n=53) and pediatric subjects without laboratory-confirmed COVID-19 included as controls (n=52) was performed. RESULTS: The median duration between COVID-19 diagnosis (n=53) and follow-up was 4.4 months (0.8-10.7). Twenty-three of 53 (43%) patients reported at least one persistent symptom at the longitudinal follow-up visit and 12/53 (23%) had long COVID-19, with at least one symptom lasting for >12 weeks. The most frequently reported symptoms at the longitudinal follow-up visit were headache (19%), severe recurrent headache (9%), tiredness (9%), dyspnea (8%), and concentration difficulty (4%). At the longitudinal follow-up visit, the frequencies of anemia (11% versus 0%, p=0.030), lymphopenia (42% versus 18%, p=0.020), C-reactive protein level of >30 mg/L (35% versus 0%, p=0.0001), and D-dimer level of >1000 ng/mL (43% versus 6%, p=0.0004) significantly reduced compared with baseline values. Chest X-ray abnormalities (11% versus 2%, p=0.178) and cardiac alterations on echocardiogram (33% versus 22%, p=0.462) were similar at both visits. Comparison of characteristic data between patients with COVID-19 at the longitudinal follow-up visit and controls showed similar age (p=0.962), proportion of male sex (p=0.907), ethnicity (p=0.566), family minimum monthly wage (p=0.664), body mass index (p=0.601), and pediatric pre-existing chronic conditions (p=1.000). The Pediatric Quality of Live Inventory 4.0 scores, median physical score (69 [0-100] versus 81 [34-100], p=0.012), and school score (60 [15-100] versus 70 [15-95], p=0.028) were significantly lower in pediatric patients with COVID-19 at the longitudinal follow-up visit than in controls. CONCLUSIONS: Pediatric patients with COVID-19 showed a longitudinal impact on HRQoL parameters, particularly in physical/school domains, reinforcing the need for a prospective multidisciplinary approach for these patients. These data highlight the importance of closer monitoring of children and adolescents by the clinical team after COVID-19.

Differences in children and adolescents with SARS-CoV-2 infection: a cohort study in a Brazilian tertiary referral hospital.

OBJECTIVES: To compare demographic/clinical/laboratory/treatments and outcomes among children and adolescents with laboratory-confirmed coronavirus disease 2019 (COVID-19). METHODS: This was a cross-sectional study that included patients diagnosed with pediatric COVID-19 (aged <18 years) between April 11, 2020 and April 22, 2021. During this period, 102/5,951 (1.7%) of all admissions occurred in neonates, children, and adolescents. Furthermore, 3,962 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection samples were processed in patients aged <18 years, and laboratory-confirmed COVID-19 occurred in 155 (4%) inpatients and outpatients. Six/155 pediatric patients were excluded from the study. Therefore, the final group included 149 children and adolescents (n=97 inpatients and 52 outpatients) with positive SARS-CoV-2 results. RESULTS: The frequencies of sore throat, anosmia, dysgeusia, headache, myalgia, nausea, lymphopenia, pre-existing chronic conditions, immunosuppressive conditions, and autoimmune diseases were significantly reduced in children and adolescents (p<0.05). Likewise, the frequencies of enoxaparin use (p=0.037), current immunosuppressant use (p=0.008), vasoactive agents (p=0.045), arterial hypotension (p<0.001), and shock (p=0.024) were significantly lower in children than in adolescents. Logistic regression analysis showed that adolescents with laboratory-confirmed COVID-19 had increased odds ratios (ORs) for sore throat (OR 13.054; 95% confidence interval [CI] 2.750-61.977; p=0.001), nausea (OR 8.875; 95% CI 1.660-47.446; p=0.011), and lymphopenia (OR 3.575; 95% CI 1.355-9.430; p=0.010), but also had less hospitalizations (OR 0.355; 95% CI 0.138-0.916; p=0.032). The additional logistic regression analysis on patients with preexisting chronic conditions (n=108) showed that death as an outcome was significantly associated with pediatric severe acute respiratory syndrome (SARS) (OR 22.300; 95% CI 2.341-212.421; p=0.007) and multisystem inflammatory syndrome in children (MIS-C) (OR 11.261; 95% CI 1.189-106. 581; p=0.035). CONCLUSIONS: Half of the laboratory-confirmed COVID-19 cases occurred in adolescents. Individuals belonging to this age group had an acute systemic involvement of SARS-CoV-2 infection. Pediatric SARS and MIS-C were the most important factors associated with the mortality rate in pediatric chronic conditions with COVID-19.

Poor Sleep quality and health-related quality of life impact in adolescents with and without chronic immunosuppressive conditions during COVID-19 quarantine.

OBJECTIVE: To assess the possible factors that influence sleep quality in adolescents with and without chronic immunosuppressive conditions quarantined during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: This cross-sectional study included 305 adolescents with chronic immunocompromised conditions and 82 healthy adolescents. Online surveys were completed, which included questions on socio-demographic data and self-rated healthcare routine during COVID-19 quarantine and the following validated questionnaires: the Pittsburgh Sleep Quality Index (PSQI), Pediatric Quality of Life Inventory 4.0 (PedsQL4.0), and Pediatric Outcome Data Collection Instrument (PODCI). RESULTS: The median current age [14 (10-18) vs. 15 (10-18) years, p=0.847] and frequency of female sex (62% vs. 58%, p=0.571) were similar in adolescents with chronic conditions compared with healthy adolescents. The frequency of poor sleep quality was similar in both groups (38% vs. 48%, p=0.118). Logistic regression analysis, including both healthy adolescents and adolescents with chronic conditions (n=387), demonstrated that self-reported increase in screen time (odds ratio [OR] 3.0; 95% confidence interval [CI] 1.3-6.8; p=0.008) and intrafamilial violence report (OR 2.1; 95% CI 1.2-3.5; p=0.008) were independently associated with poor sleep quality in these adolescents. However, the PODCI global function score was associated with a lower OR for poor sleep quality (OR 0.97; 95% CI 0.94-0.99; p=0.001). Further logistic regression, including only adolescents with chronic conditions (n=305), demonstrated that self-reported increase in screen time (OR 3.1; 95% CI 1.4-6.8; p=0.006) and intrafamilial violence report (OR 2.0; 95% CI 1.2-3.4; p=0.011) remained independently associated with poor quality of sleep, whereas a lower PODCI global function score was associated with a lower OR for sleep quality (OR 0.96; 95% CI 0.94-0.98; p<0.001). CONCLUSION: Self-reported increases in screen time and intrafamilial violence report impacted sleep quality in both healthy adolescents and those with chronic conditions. Decreased health-related quality of life was observed in adolescents with poor sleep quality.

Physical and mental health impacts during COVID-19 quarantine in adolescents with preexisting chronic immunocompromised conditions.

OBJECTIVE: To evaluate physical and mental health indicators in adolescents with preexisting chronic immunocompromised conditions during coronavirus disease 2019 (COVID-19) quarantine. METHODS: A cross-sectional study included 355 adolescents with chronic conditions and 111 healthy adolescents. An online self-rated survey was used to investigate socio-demographic features, healthcare routine, and the quarantine impact on physical and mental health. The validated self-reported version of the Strengths and Difficulties Questionnaire (SDQ) was also applied. RESULTS: The median of age [14 (10-18) vs. 15 (10-18) years, p = 0.733] and frequencies of female (61% vs. 60%, p = 0.970) were similar between adolescents with preexisting chronic conditions and healthy adolescents during quarantine of COVID-19 pandemic. The frequencies of abnormal total difficulties score of SDQ were similar in patients and controls (30% vs. 31%, p = 0.775). Logistic regression analysis showed that being female (OR = 1.965; 95% CI = 1.091-3.541, p = 0.024), fear of underlying disease activity/complication (OR = 1.009; 95%CI = 1.001-1.018, p = 0.030) were associated with severe psychosocial dysfunction in adolescents with chronic conditions, whereas school homework (OR = 0.449; 95% CI = 0.206-0.981, p = 0.045) and physical activity (OR = 0.990; 95% CI = 0.981-0.999, p = 0.030) were protective factors. Further analysis of patients with chronic immunocompromised conditions and previous diagnosis of mental disorders (9%) compared with patients without diagnosis showed higher median of total difficulties score (p = 0.001), emotional (p = 0.005), conduct (p = 0.007), peer problems (p = 0.001) and hyperactivity (p = 0.034) in the former group. CONCLUSION: Adolescents with preexisting chronic immunocompromised conditions during COVID-19 quarantine were not at higher risk of adverse health indicators. Being female, fear of underlying disease activity/complication, and household members working outside of the home were relevant issues for adolescents with preexisting chronic conditions. This study reinforces the need to establish mental health strategies for teens with chronic conditions, particularly during the pandemic.

The Heart of Pediatric Patients with COVID-19: New Insights from a Systematic Echocardiographic Study in a Tertiary Hospital in Brazil. / O Coração de Pacientes Pediátricos com COVID-19: Novos Insights a Partir de um Estudo Ecocardiográfico Sistemático em um Hospital Terciário no Brasil.

BACKGROUND: COVID-19 pandemic represents a huge burden to the health system in the world. Although pediatric COVID-19 patients have been relatively spared compared with adults, recent reports showed an increasing number of critically ill patients with multisystemic inflammatory syndrome in children (MIS-c), with marked cardiovascular impairment. Nevertheless, little is known about the relationship between cardiac abnormalities and inflammatory and coagulation biomarkers. OBJECTIVES: to investigate echocardiographic abnormalities in pediatric patients with COVID-19 admitted to tertiary hospital. METHODS: this was a retrospective longitudinal study, based on the review of medical records and echocardiograms of patients (0-19 years) admitted to a tertiary hospital between March 30 and June 30, 2020. For statistical analysis, the significance level was set at 5% (p < 0.05). RESULTS: Forty-eight patients were enrolled, 73% with preexisting diseases, 20 (41.7%) with MIS-c. Median age was 7.5 (0-18.6) years; 27 (56.2%) were male. Median duration of hospitalization was 15.4 (2-92) days and seven (14.6%) patients died. A total of 70 echocardiograms were performed; 66.7% patients were scanned only once and 33.3% multiple times. Twenty-three (48%) patients showed echocardiographic abnormalities: eight (16.6%) left ventricle (LV) systolic dysfunction, six (12.5%) right ventricle (RV) systolic dysfunction and 12 (25%) coronary dilatation (Z-score>+2.5). Echocardiographic abnormalities were significantly associated with MIS-c, admission to the pediatric intensive care unit, multiple organ dysfunction, ventilatory/vasoactive support, and death (p<0.05). Significantly higher d-dimer (ng/mL) levels were detected in patients with LV dysfunction [16733(4157-115668) vs. 2406.5(190-95040)], RV dysfunction [25769(3422-115668) vs. 2803.5(190-95040)] and coronary artery dilation [9652.5(921-115668) vs. 2724(190- 95040)] (p<0.05). CONCLUSION: Echocardiographic abnormalities in COVID-19 pediatric patients were frequent and associated with worse clinical outcomes. Exacerbation of the inflammation and coagulation pathways may play an important role in cardiovascular injury in those patients.

FUNDAMENTO: A pandemia da COVID-19 representa uma enorme carga para o sistema de saúde do mundo. Apesar de pacientes pediátricos terem sido relativamente poupados em comparação a adultos, estudos recentes mostraram um número crescente de pacientes críticos com Síndrome Inflamatória Multisistêmica Pediátrica (SIM-P) com disfunção cardiovascular importante. No entanto, pouco se conhece a respeito da relação entre anormalidades cardíacas e biomarcadores inflamatórios e de coagulação. OBJETIVOS: Investigar anormalidades ecocardiográficas em pacientes pediátricos com COVID-19 admitidos em um hospital terciário. MÉTODOS: Este foi um estudo longitudinal retrospectivo, baseado na revisão de prontuários médicos e ecocardiogramas de pacientes (0-19 anos) admitidos em um hospital terciário entre 30 de março e 30 de junho de 2020. Para a análise estatística, o nível de significância foi estabelecido em 5% (p<0,05). RESULTADOS: Foram incluídos 48 pacientes, 73% com doenças pré-existentes, 20 (41,7%) com SIM-P. A idade mediana foi 7,5 (0-18,6) anos; 27 (56,2%) eram do sexo masculino. A duração mediana de internação foi 15,4 (2-92) dias e sete (14,6%) pacientes morreram. Um total de 70 ecocardiografias foram realizadas, 66,7% submeteram-se ao exame somente uma vez, e 33,3% várias vezes. Vinte e três (48%) pacientes apresentaram anormalidades no ecocardiograma: oito (16.6%) disfunção sistólica do ventrículo esquerdo, seis (12.5%) disfunção sistólica do ventrículo direito, e 12 (25%) dilatação da artéria coronária (Z-score>+2,5). Anormalidades ecocardiográficas foram significativamente associadas com SIM-P, admissão na unidade de terapia intensiva pediátrica, suporte ventilatório/vasoativo, e morte ( p <0,05). Níveis significativamente mais altos de d-dímero (ng/mL) foram detectados em pacientes com disfunção ventricular esquerda [16733(4157-115668) vs. 2406.5(190-95040)], disfunção ventricular direita [25769(3422-115668) vs. 2803.5(190-95040)] e dilatação da artéria coronária [9652.5(921-115668) vs. 2724(190- 95040)] (p<0,05). CONCLUSÃO: Anormalidades ecocardiográficas eram frequentes nos pacientes pediátricos com COVID-19 e associadas com piores desfechos clínicos. Exacerbação das vias de inflamação e coagulação pode exercer um importante papel na lesão cardiovascular nesses pacientes.

Severe clinical spectrum with high mortality in pediatric patients with COVID-19 and multisystem inflammatory syndrome

OBJECTIVES: To assess the outcomes of pediatric patients with laboratory-confirmed coronavirus disease (COVID-19) with or without multisystem inflammatory syndrome in children (MIS-C). METHODS: This cross-sectional study included 471 samples collected from 371 patients (age&lt;18 years) suspected of having severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The study group comprised 66/371 (18%) laboratory-confirmed pediatric COVID-19 patients: 61 (92.5%) patients tested positive on real-time reverse transcription-polymerase chain reaction tests for SARS-CoV-2, and 5 (7.5%) patients tested positive on serological tests. MIS-C was diagnosed according to the criteria of the Center for Disease Control. RESULTS: MIS-C was diagnosed in 6/66 (9%) patients. The frequencies of diarrhea, vomiting, and/or abdominal pain (67% vs. 22%, p=0.034);pediatric SARS (67% vs. 13%, p=0.008);hypoxemia (83% vs. 23%, p=0.006);and arterial hypotension (50% vs. 3%, p=0.004) were significantly higher in patients with MIS-C than in those without MIS-C. The frequencies of C-reactive protein levels &gt;50 mg/L (83% vs. 25%, p=0.008) and D-dimer levels &gt;1000 ng/mL (100% vs. 40%, p=0.007) and the median D-dimer, troponin T, and ferritin levels (p&lt;0.05) were significantly higher in patients with MIS-C. The frequencies of pediatric intensive care unit admission (100% vs. 60%, p=0.003), mechanical ventilation (83% vs. 7%, p&lt;0.001), vasoactive agent use (83% vs. 3%, p&lt;0.001), shock (83% vs. 5%, p&lt;0.001), cardiac abnormalities (100% vs. 2%, p&lt;0.001), and death (67% vs. 3%, p&lt;0.001) were also significantly higher in patients with MIS-C. Similarly, the frequencies of oxygen therapy (100% vs. 33%, p=0.003), intravenous immunoglobulin therapy (67% vs. 2%, p&lt;0.001), aspirin therapy (50% vs. 0%, p&lt;0.001), and current acute renal replacement therapy (50% vs. 2%, p=0.002) were also significantly higher in patients with MIS-C. Logistic regression analysis showed that the presence of MIS-C was significantly associated with gastrointestinal manifestations [odds ratio (OR)=10.98;95%CI (95% confidence interval)=1.20-100.86;p=0.034] and hypoxemia [OR=16.85;95%CI=1.34-211.80;p=0.029]. Further univariate analysis showed a positive association between MIS-C and death [OR=58.00;95%CI=6.39-526.79;p&lt;0.0001]. CONCLUSIONS: Pediatric patients with laboratory-confirmed COVID-19 with MIS-C had a severe clinical spectrum with a high mortality rate. Our study emphasizes the importance of investigating MIS-C in pediatric patients with COVID-19 presenting with gastrointestinal involvement and hypoxemia.

Brazilian Consortium for the Study on Renal Diseases Associated With COVID-19: A Multicentric Effort to Understand SARS-CoV-2-Related Nephropathy.

Kidney involvement appears to be frequent in coronavirus disease 2019 (COVID-19). Despite this, information concerning renal involvement in COVID-19 is still scarce. Several mechanisms appear to be involved in the complex relationship between the virus and the kidney. Also, different morphological patterns have been described in the kidneys of patients with COVID-19. For some authors, however, this association may be just a coincidence. To investigate this issue, we propose assessing renal morphology associated with COVID-19 at the renal pathology reference center of federal university hospitals in Brazil. Data will come from a consortium involving 17 federal university hospitals belonging to Empresa Brasileira de Serviços Hospitalares (EBSERH) network, as well as some state hospitals and an autopsy center. All biopsies will be sent to the referral center for renal pathology of the EBSERH network. The data will include patients who had coronavirus disease, both alive and deceased, with or without pre-existing kidney disease. Kidney biopsies will be analyzed by light, fluorescence, and electron microscopy. Furthermore, immunohistochemical (IHC) staining for various inflammatory cells (i.e., cells expressing CD3, CD20, CD4, CD8, CD138, CD68, and CD57) as well as angiotensin-converting enzyme 2 (ACE2) will be performed on paraffinized tissue sections. In addition to ultrastructural assays, in situ hybridization (ISH), IHC and reverse transcription-polymerase chain reaction (RT-PCR) will be used to detect Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) in renal tissue. For the patients diagnosed with Collapsing Glomerulopathy, peripheral blood will be collected for apolipoprotein L-1 (APOL1) genotyping. For patients with thrombotic microangiopathy, thrombospondin type 1 motif, member 13 (ADAMTS13), antiphospholipid, and complement panel will be performed. The setting of this study is Brazil, which is second behind the United States in highest confirmed cases and deaths. With this complete approach, we hope to help define the spectrum and impact, whether immediate or long-term, of kidney injury caused by SARS-CoV-2.

Severe clinical spectrum with high mortality in pediatric patients with COVID-19 and multisystem inflammatory syndrome.

OBJECTIVES: To assess the outcomes of pediatric patients with laboratory-confirmed coronavirus disease (COVID-19) with or without multisystem inflammatory syndrome in children (MIS-C). METHODS: This cross-sectional study included 471 samples collected from 371 patients (age<18 years) suspected of having severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The study group comprised 66/371 (18%) laboratory-confirmed pediatric COVID-19 patients: 61 (92.5%) patients tested positive on real-time reverse transcription-polymerase chain reaction tests for SARS-CoV-2, and 5 (7.5%) patients tested positive on serological tests. MIS-C was diagnosed according to the criteria of the Center for Disease Control. RESULTS: MIS-C was diagnosed in 6/66 (9%) patients. The frequencies of diarrhea, vomiting, and/or abdominal pain (67% vs. 22%, p=0.034); pediatric SARS (67% vs. 13%, p=0.008); hypoxemia (83% vs. 23%, p=0.006); and arterial hypotension (50% vs. 3%, p=0.004) were significantly higher in patients with MIS-C than in those without MIS-C. The frequencies of C-reactive protein levels >50 mg/L (83% vs. 25%, p=0.008) and D-dimer levels >1000 ng/mL (100% vs. 40%, p=0.007) and the median D-dimer, troponin T, and ferritin levels (p<0.05) were significantly higher in patients with MIS-C. The frequencies of pediatric intensive care unit admission (100% vs. 60%, p=0.003), mechanical ventilation (83% vs. 7%, p<0.001), vasoactive agent use (83% vs. 3%, p<0.001), shock (83% vs. 5%, p<0.001), cardiac abnormalities (100% vs. 2%, p<0.001), and death (67% vs. 3%, p<0.001) were also significantly higher in patients with MIS-C. Similarly, the frequencies of oxygen therapy (100% vs. 33%, p=0.003), intravenous immunoglobulin therapy (67% vs. 2%, p<0.001), aspirin therapy (50% vs. 0%, p<0.001), and current acute renal replacement therapy (50% vs. 2%, p=0.002) were also significantly higher in patients with MIS-C. Logistic regression analysis showed that the presence of MIS-C was significantly associated with gastrointestinal manifestations [odds ratio (OR)=10.98; 95%CI (95% confidence interval)=1.20-100.86; p=0.034] and hypoxemia [OR=16.85; 95%CI=1.34-211.80; p=0.029]. Further univariate analysis showed a positive association between MIS-C and death [OR=58.00; 95%CI=6.39-526.79; p<0.0001]. CONCLUSIONS: Pediatric patients with laboratory-confirmed COVID-19 with MIS-C had a severe clinical spectrum with a high mortality rate. Our study emphasizes the importance of investigating MIS-C in pediatric patients with COVID-19 presenting with gastrointestinal involvement and hypoxemia.