Imaging findings of acute calcific periarthritis, with emphasis on magnetic resonance imaging: pictorial essay.

Acute calcific periarthritis (ACP) is defined as periarticular inflammation associated with intra-articular deposits of hydroxyapatite and other basic calcium phosphate crystals. Patients with ACP present with a sudden onset of pain, together with localized swelling, as well as erythema, tenderness, and reduced range of motion. Familiarity with the clinical and radiological manifestations of ACP aids in the diagnosis and helps differentiate it from other conditions, particularly infectious or inflammatory pathologies such as septic arthritis and gout, thereby reducing the number of unnecessary diagnostic and therapeutic procedures. The objective of this pictorial essay is to illustrate the imaging findings of ACP in various joints, with an emphasis on the findings obtained by magnetic resonance imaging.

A periartrite cálcica aguda (PCA) é uma inflamação periarticular aguda associada a depósitos justa-articulares de hidroxiapatita e outros cristais básicos de fosfato de cálcio. Os pacientes apresentam início súbito de dor, edema localizado, eritema, sensibilidade e redução da amplitude de movimentos. A familiaridade com as manifestações clínicas e radiológicas da PCA facilita o diagnóstico e permite diferenciá-la de outras entidades, em particular, com doenças infecciosas ou inflamatórias, como artrite séptica e gota, reduzindo procedimentos diagnósticos e terapêuticos desnecessários. O objetivo deste ensaio iconográfico é ilustrar os achados de imagem de PCA em algumas articulações, com ênfase na ressonância magnética.

Imaging findings of acute calcific periarthritis, with emphasis on magnetic resonance imaging: pictorial essay / Achados de imagem da periartrite cálcica aguda, com ênfase na ressonância magnética: ensaio iconográfico

Abstract Acute calcific periarthritis (ACP) is defined as periarticular inflammation associated with intra-articular deposits of hydroxyapatite and other basic calcium phosphate crystals. Patients with ACP present with a sudden onset of pain, together with localized swelling, as well as erythema, tenderness, and reduced range of motion. Familiarity with the clinical and radiological manifestations of ACP aids in the diagnosis and helps differentiate it from other conditions, particularly infectious or inflammatory pathologies such as septic arthritis and gout, thereby reducing the number of unnecessary diagnostic and therapeutic procedures. The objective of this pictorial essay is to illustrate the imaging findings of ACP in various joints, with an emphasis on the findings obtained by magnetic resonance imaging.

Resumo A periartrite cálcica aguda (PCA) é uma inflamação periarticular aguda associada a depósitos justa-articulares de hidroxiapatita e outros cristais básicos de fosfato de cálcio. Os pacientes apresentam início súbito de dor, edema localizado, eritema, sensibilidade e redução da amplitude de movimentos. A familiaridade com as manifestações clínicas e radiológicas da PCA facilita o diagnóstico e permite diferenciá-la de outras entidades, em particular, com doenças infecciosas ou inflamatórias, como artrite séptica e gota, reduzindo procedimentos diagnósticos e terapêuticos desnecessários. O objetivo deste ensaio iconográfico é ilustrar os achados de imagem de PCA em algumas articulações, com ênfase na ressonância magnética.

Methodology for the estimation of an oil spill origin: Analysis of the 2019 Brazilian coast oil spill.

This research presents a procedure for determining the origin of marine pollution through the use of a time-direct trajectory modeling, associated with a Kriging metamodel technique and Monte Carlo random sampling. These methods were applied to a real case, specifically the oil spill that affected the Brazilian coast in the second half of 2019 and early 2020. A total of 140 trajectories, defined by the geographical coordinates of the origin and the spill date, were generated through Latin Hypercube Sampling and simulated using the PyGNOME model to construct the Kriging metamodel. The metamodel demonstrated cost-effectiveness by efficiently simulating numerous input data combinations which were compared and optimized based on available real data regarding temporal and spatial pollution distribution.

Radiographic findings in acromegaly: pictorial essay.

Acromegaly is an uncommon metabolic disorder, often diagnosed after a long delay. One symptom seen in many patients with acromegaly is arthralgia, a finding that calls for the use of conventional radiography, which can reveal subtle changes that can go unnoticed. The objective of this pictorial essay is to portray the radiographic aspects of acromegaly, seeking to demonstrate the importance of conventional radiography, which, despite its simplicity, can suggest the diagnosis, even in the early stages, thus altering the clinical course of the disease.

A acromegalia é um distúrbio metabólico pouco frequente, muitas vezes apresentando grande atraso diagnóstico. A artralgia é um dos sintomas mais comumente encontrados nos pacientes acromegálicos, motivando a realização de radiografias convencionais, as quais podem apresentar achados sutis que podem passar despercebidos. O objetivo deste ensaio é retratar os achados radiográficos da acromegalia, buscando demonstrar a importância deste método que, apesar de simples, pode sugerir o diagnóstico, mesmo em fases iniciais, alterando assim o curso clínico da doença.

Virus-Like Particle-Encapsulated Doxorubicin Enters and Kills Murine Tumor Cells Differently from Free Doxorubicin.

The use of nanoparticles as chemotherapeutic carriers has been suggested as a way to overcome a range of side effects associated with classical cancer treatment such as poor selectivity and tumor resurgence. Obtaining precise control of the size and shape of therapeutic nanoparticles is crucial to optimize the targeting of tumor sites. In this work, it is shown that a previously developed system of polypeptide encapsulating individual DNA molecules, that forms rod-shaped nanoparticles of precisely controlled aspect ratio, can be loaded with the DNA-intercalating chemotherapeutic drug doxorubicin (DOX). It is characterized the size and shape of the DOX loaded-Virus-Like DNA Particles (DOX-VLDP) and shown that in this system the DOX payload does not leak out. Through in vitro cell studies, it is shown that DOX-VLDP is internalized by melanoma tumor cells (B16F10 cells) in a delayed and endocytosis-dependent way culminating in increased cytotoxicity and selectivity to tumor cells in comparison with free DOX. In addition, it is found that DOX-VLDP trigger apoptosis and autophagy pathways in treated cells. Taken together, the data on the DOX-VLDP nanoparticles shows that they kill cancer cells differently from free DOX.

The influence of N95 and FFP2 masks on cardiorespiratory variables in healthy individuals during aerobic exercise: a systematic review and meta-analysis.

OBJECTIVE: In view of the current COVID-19 pandemic, the objective of this study was to determine, through a systematic review and meta-analysis, whether the use of N95/FFP2 masks during aerobic exercise has a significant impact on HR, RR, SpO2, and blood pressure (BP) in healthy individuals. METHODS: We searched the MEDLINE database for studies published in English between 2005 and 2021. To reduce bias and increase reliability, only randomized controlled trials and randomized crossover clinical trials were considered for inclusion. The selected outcomes included HR, RR, SpO2, and BP, with perceived exertion being evaluated by means of the Borg scale. RESULTS: Eight controlled trials were included in the meta-analysis. Seven evaluated HR (p > 0.05), five evaluated RR (p > 0.05), five evaluated SpO2 and BP (p > 0.05 for both), and six evaluated perceived exertion, presenting controversial results such as risk ratios that were grouped for each variable. CONCLUSIONS: This study suggests that N95 and FFP2 masks do not have significant effects on HR, RR, SpO2, and BP during aerobic exercise in healthy individuals.

Radiographic findings in acromegaly: pictorial essay / Achados radiográficos da acromegalia: ensaio iconográfico

Abstract Acromegaly is an uncommon metabolic disorder, often diagnosed after a long delay. One symptom seen in many patients with acromegaly is arthralgia, a finding that calls for the use of conventional radiography, which can reveal subtle changes that can go unnoticed. The objective of this pictorial essay is to portray the radiographic aspects of acromegaly, seeking to demonstrate the importance of conventional radiography, which, despite its simplicity, can suggest the diagnosis, even in the early stages, thus altering the clinical course of the disease.

Resumo A acromegalia é um distúrbio metabólico pouco frequente, muitas vezes apresentando grande atraso diagnóstico. A artralgia é um dos sintomas mais comumente encontrados nos pacientes acromegálicos, motivando a realização de radiografias convencionais, as quais podem apresentar achados sutis que podem passar despercebidos. O objetivo deste ensaio é retratar os achados radiográficos da acromegalia, buscando demonstrar a importância deste método que, apesar de simples, pode sugerir o diagnóstico, mesmo em fases iniciais, alterando assim o curso clínico da doença.

Landscapes of Biochemical Warfare: Spatial Self-Organization Woven from Allelopathic Interactions.

Evidence shows that diversity and spatial distributions of biological communities are largely driven by the race of living organisms in their adaptation to chemicals synthesized by their neighbors. In this report, the emergence of mathematical models on pure spatial self-organization induced by biochemical suppression (allelopathy) and competition between species were investigated through numerical analysis. For both random and patched initial spatial distributions of species, we demonstrate that warfare survivors are self-organized on the landscape in Turing-like patterns driven by diffusive instabilities of allelochemicals. These patterns are simple; either all species coexist at low diffusion rates or are massively extinct, except for a few at high diffusivities, but they are complex and biodiversity-sustained at intermediate diffusion rates. "Defensive alliances" and ecotones seem to be basic mechanisms that sustain great biodiversity in our hybrid cellular automata model. Moreover, species coexistence and extinction exhibit multi-stationarity.

Corrigendum: A head-to-head comparison of myocardial strain by fast-strain encoding and feature tracking imaging in acute myocardial infarction.

[This corrects the article DOI: 10.3389/fcvm.2022.949440.].

Evaluation of teaching low intensity laser in perspective dentist

Search knowledge dentist front surgeon to low intensity laser through a questionnaire. They were selected randomly in the city of Juiz de Fora and region 91 Dental Surgeons of Minas Gerais. These employees were sent during the months from July to October 2013, a standard form printed with questions about laser education assessment of low intensity. Of the 91 participants, 42 (46.2%) were female and 49 (53.8%) were male. Fifty-seven (62.6%) had dental public institution of higher education; 32 (35.2%) attended a private institution and 2 (2.2%) did not report this data. Eighty-nine dentists reported the time of graduation, and this varied with a minimum of 1 year and a maximum of 38 years of training, the average being 11 years and this is the standard deviation of 10.7. The age of these professionals is on average thirty-five years, ranging from twenty-two years to sixty-five years of age and the standard deviation of this is 10.8. The distribution according to academic title was: 35 dentists (38.5%) had a degree in dentistry; 13 (14.3%) were specialists; 14 (15.4%) had master's and 4 (4.4%) doctorate. 25 (27.5%) did not report the academic title. The most relevant mentioned specialties were general practitioner, endodontics and implantology. We can conclude that the Juiz de Fora dentist - MG and region makes little use of laser therapy and this is mainly due to little knowledge acquired at the undergraduate and graduate education.

Pro-adherence complementary audiovisual educational intervention model for chronic myeloid leukemia patients treated with imatinib mesylate.

BACKGROUND: Imatinib mesylate (IM) treatment adherence is a challenge, especially in an economic-social population neglected from developing countries. OBJECTIVE: To create a new complementary audiovisual educational intervention model to improve IM treatment adherence of CML patients. METHODS: Two adherence verification methods were applied before and after intervention: modified Morisky-Green test and molecular responses (BCR-ABL transcripts quantification). Adherence estimates were calculated using univariate and multivariate component analysis (MCA) for the socio-demographic and clinical characteristics of patients. RESULTS: Modified Morisky-Green test results demonstrated a substantial increase of CML patient adherence from 23% (pre-film) to 65% (post-film). Greater improvement was obtained for patients presenting major molecular response (MMR) from 38% (pre-film) to 60% (post-film). Although slight gain for complete molecular response (CMR) from 23% (pre-film) to 26% (post-film) was achieved, it represents a total tumour regression. MCA identified that females <50 years-old, using less than two medications (no disease associated) and CMR condition were the most benefited with intervention. CONCLUSION: Audiovisual educational intervention was an effective complementary pro-adherence model, activating patient memory and improving IM treatment adherence. Although this intervention shows effective, not all patients responded as expected, being necessary a combination of educational and clinical interventions to improve IM adherence.

The influence of N95 and FFP2 masks on cardiorespiratory variables in healthy individuals during aerobic exercise: a systematic review and meta-analysis / A influência das máscaras N95 e PFF2 sobre variáveis cardiorrespiratórias em indivíduos saudáveis durante o exercício aeróbico: revisão sistemática e meta-análise

ABSTRACT Objective: In view of the current COVID-19 pandemic, the objective of this study was to determine, through a systematic review and meta-analysis, whether the use of N95/FFP2 masks during aerobic exercise has a significant impact on HR, RR, SpO2, and blood pressure (BP) in healthy individuals. Methods: We searched the MEDLINE database for studies published in English between 2005 and 2021. To reduce bias and increase reliability, only randomized controlled trials and randomized crossover clinical trials were considered for inclusion. The selected outcomes included HR, RR, SpO2, and BP, with perceived exertion being evaluated by means of the Borg scale. Results: Eight controlled trials were included in the meta-analysis. Seven evaluated HR (p > 0.05), five evaluated RR (p > 0.05), five evaluated SpO2 and BP (p > 0.05 for both), and six evaluated perceived exertion, presenting controversial results such as risk ratios that were grouped for each variable. Conclusions: This study suggests that N95 and FFP2 masks do not have significant effects on HR, RR, SpO2, and BP during aerobic exercise in healthy individuals.

RESUMO Objetivo: Diante da atual pandemia de COVID-19, o objetivo deste estudo foi determinar, por meio de uma revisão sistemática e meta-análise, se o uso de máscaras N95/PFF2 durante o exercício aeróbico tem impacto significativo na FC, FR, SpO2 e pressão arterial (PA) em indivíduos saudáveis. Métodos: Buscamos no banco de dados MEDLINE estudos publicados em inglês entre 2005 e 2021. Para reduzir o viés e aumentar a confiabilidade, foram considerados para inclusão no estudo somente ensaios clínicos controlados randomizados e ensaios clínicos cruzados randomizados. Os desfechos selecionados foram FC, FR, SpO2 e PA; a percepção de esforço foi avaliada por meio da escala de Borg. Resultados: Oito ensaios controlados foram incluídos na meta-análise. Sete avaliaram FC (p > 0,05), cinco avaliaram FR (p > 0,05), cinco avaliaram SpO2 e PA (p > 0,05 para ambas) e seis avaliaram a percepção de esforço, com resultados controversos (razões de risco agrupadas para cada variável, por exemplo). Conclusões: Este estudo sugere que as máscaras N95 e PFF2 não têm efeitos significativos na FC, FR, SpO2 e PA durante o exercício aeróbico em indivíduos saudáveis.

Safety of the Fiocruz ChAdOx COVID-19 vaccine used in a mass vaccination campaign in Botucatu, Brazil.

INTRODUCTION: Brazil has been at the core of the COVID-19 pandemic, with the second-highest death toll worldwide. A mass vaccination campaign was initiated on May 16th, 2021, in Botucatu, Brazil, where two doses of ChadOx1-nCoV19 were offered 12 weeks apart to all 18-60- year-olds. This context offers a unique opportunity to study the vaccine safety during a mass campaign. METHODS: The first and second doses of the vaccine were administered in May and August 2021, respectively. Emergency room (ER) and hospitalization records were obtained from the Hospital das Clínicas da Faculdade de Medicina de Botucatu for six weeks before and six weeks after the first and second doses, from 4 April to 19 September 2021. Diagnoses with COVID-19-related ICD codes were excluded to distinguish any trends resulting from the COVID-19 pandemic. ER and hospital visits during the two time periods were compared, including an ICD code comparison, to identify any changes in disease distributions. Data were scanned for a defined list of Adverse Events of Special Interest (AESIs), as presented by the Safety Platform for Emergency Vaccines. RESULTS AND DISCUSSION: A total of 77,683 and 74,051 subjects received dose 1 and dose 2 of ChadOx1-nCoV19, respectively. Vaccination was well tolerated and not associated with any major safety concerns. Increases in ER visits 1 week following both doses were primarily seen in ICD codes related to non-serious side effects of the vaccine, including vaccination site pain and other local events. The neurological AESIs identified (2 of 3 cases of multiple sclerosis) were relapses of a pre-existing condition. One potentially serious hospitalization event for Bell's palsy had onset before vaccination with dose 1, in a patient who also had a viral infection of the central nervous system. There was no myocarditis, pericarditis cases, or vaccine-related increases in thromboembolic events.

Epidural morphine for chronic pain in a patient with peripheral neuropathy and DRESS syndrome. Case report / Morfina peridural para tratamento de dor crônica em paciente com polineuropatia periférica e síndrome DRESS. Relato de caso

ABSTRACT BACKGROUND AND OBJECTIVES: Peripheral neuropathy is a rare condition with many etiologies. Common symptoms are numbness, paresthesia, weakness and neuropathic pain. Treatment consists in frst-line agents such as anticonvulsants and some antidepressants. Te aim of this study was to report a case of chronic pain refractory to several therapies in a patient with absolute contraindication to the use of all anticonvulsants and antidepressants drugs. CASE REPORT: Female patient, a 40-year-old treated for trigeminal neuralgia with decompression that developed chronic occipital pain refractory to radiofrequency and onset of transient and bilateral T4 sensory and motor polyneuropathy after viral meningitis. In addition, she showed a severe pharmacodermy (Drug Rash with Eosinophilia and Systemic Symptoms- DRESS Syndrome) after using carbamazepine and other anticonvulsants, as well as allergy to all analgesics and opioids except morphine. Epidural puncture with insertion of a catheter was performed aiming at a 5-day test through intermittent epidural morphine bolus to assess the possibility of morphine pump implantation. CONCLUSION: The test was successful and the patient referred to the neurosurgery team. At the 6-month follow-up after the insertion of the morphine intrathecal pump, the strategy has proven to be efective in controlling pain secondary to polyneuropathy.

RESUMO JUSTIFICATIVA E OBJETIVOS: Neuropatia periférica é uma condição rara, de etiologia multifatorial. Dormência, parestesia, redução de força muscular e dor neuropática são sintomas comuns. O tratamento consiste em uso de anticonvulsivantes e antidepressivos. O objetivo deste estudo foi relatar o caso de dor crônica refratária a diversas terapias de uma paciente com contraindicação absoluta para uso de todos os fármacos anticonvulsivantes e antidepressivos. RELATO DO CASO: Paciente do sexo feminino, 40 anos, com história de neuralgia do trigêmeo abordada previamente com cirurgia, com cefaleia occipital crônica refratária à radiofrequência e polineuropatia bilateral T4 sensorial e motora após meningite viral. No curso do tratamento, apresentou grave farmacodermia (Drug Rash with Eosinophilia and Systemic Symptoms - Síndrome DRESS) após o uso de carbamazepina e outros anticonvulsivantes, além de reação alérgica a todos analgésicos e opioides, exceto morfina. Optou-se por analgesia teste por via peridural, durante 5 dias, com bolus intermitentes e diários de morfina para avaliação de possibilidade de implante de bomba de morfina. CONCLUSÃO: O teste foi considerado bem-sucedido e a paciente encaminhada para neurocirurgia. No seguimento de 6 meses após implante de bomba por via subaracnoidea, esta estratégia se mostrou eficaz no controle da dor secundária à polineuropatia.

A head-to-head comparison of myocardial strain by fast-strain encoding and feature tracking imaging in acute myocardial infarction.

Background: Myocardial infarction (MI) is a major cause of heart failure. Left ventricular adverse remodeling is common post-MI. Several studies have demonstrated a correlation between reduced myocardial strain and the development of adverse remodeling. Cardiac magnetic resonance (CMR) with fast-strain encoding (fast-SENC) or feature tracking (FT) enables rapid assessment of myocardial deformation. The aim of this study was to establish a head-to-head comparison of fast-SENC and FT in post-ST-elevated myocardial infarction (STEMI) patients, with clinical 2D speckle tracking echocardiography (2DEcho) as a reference. Methods: Thirty patients treated with primary percutaneous coronary intervention for STEMI were investigated. All participants underwent CMR examination with late gadolinium enhancement, cine-loop steady-state free precession, and fast-SENC imaging using a 1.5T scanner as well as a 2DEcho. Global longitudinal strain (GLS), segmental longitudinal strain (SLS), global circumferential strain (GCS), and segmental circumferential strain (SCS) were assessed along with the MI scar extent. Results: The GCS measurements from fast-SENC and FT were nearly identical: the mean difference was 0.01 (2.5)% (95% CI - 0.92 to 0.95). For GLS, fast-SENC values were higher than FT, with a mean difference of 1.8 (1.4)% (95% CI 1.31-2.35). Tests of significance for GLS did not show any differences between the MR methods and 2DEcho. Average strain in the infarct-related artery (IRA) segments compared to the remote myocardium was significantly lower for the left anterior descending artery and right coronary artery culprits but not for the left circumflex artery culprits. Fast-SENC displayed a higher area under the curve for detecting infarcted segments than FT for both SCS and SLS. Conclusion: GLS and GCS did not significantly differ between fast-SENC and FT. Both showed acceptable agreement with 2DEcho for longitudinal strain. Segments perfused by the IRA showed significantly reduced strain values compared to the remote myocardium. Fast-SENC presented a higher sensitivity and specificity for detecting infarcted segments than FT.

Are there sex differences in energy expenditure and enjoyment in older adults playing active video games?

The aim of this study was to compare sex differences in energy expenditure and enjoyment in older adults during Active Video Game activities and sedentary behavior (watching television). In a within-subjects design, n = 32 older adults were included (15 men and 17 women). Energy expenditure was measured during each activity using indirect calorimetry. Energy expenditure was expressed in J.kg-1.min-1 and Metabolic Equivalents. Enjoyment was measured after each activity with the Physical Activity Enjoyment Scale. Energy expenditure was greater in Active Video Game activities compared to sedentary behavior in both men and women, but no differences were observed between sexes. The women reported greater enjoyment in Active Video Game activities compared to the men, and women reported greater enjoyment in Active Video Game activities compared to watching television, whereas the men did not report differences in enjoyment between Active Video Game vs. television watching. In conclusion, despite no difference in Energy expenditure, older women enjoy more than men playing Active Video Game, maybe they can be targeted for this intervention. (Clinical Trials Registration - NCT04352543).

Impact of facial profile on young adults' oral health-related quality-of-life item levels: A hierarchical analysis.

OBJECTIVE: To assess the impact of facial profile on young adults' oral health-related quality of life (OHRQoL) item levels. METHODS: A cross-sectional study was carried out with a population-based sample of 205 young adults, with a mean age of 23.1 years. The individuals answered questions about OHRQoL (OHIP-14) and self-esteem (Global Negative Self-Evaluation). The Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN) was used to evaluate normative orthodontic treatment needs and define dental malocclusion clinically. Facial profile was analyzed using photographs and dichotomized into two levels: normal (straight) and altered facial profile (convex or concave). A calibrated researcher performed the clinical examination. Association between the independent variables and the outcome (OHRQoL) was established by hierarchical multiple linear regression analysis for each item level. Considering the variable of interest (facial profile), the psychological incapacity domain was the most affected item. RESULTS: Individuals with changed facial profile had 2.47 (1.04-5.85) times higher chances of reporting impacts on psychological incapacity than those with a normal profile (p> 0.05). The association was modulated by dental malocclusion and self-esteem. CONCLUSIONS: The convex and concave facial profile showed a negative impact on the psychological aspects of young adults' quality of life.

Authorship Correction: International Changes in COVID-19 Clinical Trajectories Across 315 Hospitals and 6 Countries: Retrospective Cohort Study.

[This corrects the article DOI: 10.2196/31400.].

Towards Interpretable Deep Learning: A Feature Selection Framework for Prognostics and Health Management Using Deep Neural Networks.

In the last five years, the inclusion of Deep Learning algorithms in prognostics and health management (PHM) has led to a performance increase in diagnostics, prognostics, and anomaly detection. However, the lack of interpretability of these models results in resistance towards their deployment. Deep Learning-based models fall within the accuracy/interpretability tradeoff, which means that their complexity leads to high performance levels but lacks interpretability. This work aims at addressing this tradeoff by proposing a technique for feature selection embedded in deep neural networks that uses a feature selection (FS) layer trained with the rest of the network to evaluate the input features' importance. The importance values are used to determine which will be considered for deployment of a PHM model. For comparison with other techniques, this paper introduces a new metric called ranking quality score (RQS), that measures how performance evolves while following the corresponding ranking. The proposed framework is exemplified with three case studies involving health state diagnostics and prognostics and remaining useful life prediction. Results show that the proposed technique achieves higher RQS than the compared techniques, while maintaining the same performance level when compared to the same model but without an FS layer.

International Changes in COVID-19 Clinical Trajectories Across 315 Hospitals and 6 Countries: Retrospective Cohort Study.

BACKGROUND: Many countries have experienced 2 predominant waves of COVID-19-related hospitalizations. Comparing the clinical trajectories of patients hospitalized in separate waves of the pandemic enables further understanding of the evolving epidemiology, pathophysiology, and health care dynamics of the COVID-19 pandemic. OBJECTIVE: In this retrospective cohort study, we analyzed electronic health record (EHR) data from patients with SARS-CoV-2 infections hospitalized in participating health care systems representing 315 hospitals across 6 countries. We compared hospitalization rates, severe COVID-19 risk, and mean laboratory values between patients hospitalized during the first and second waves of the pandemic. METHODS: Using a federated approach, each participating health care system extracted patient-level clinical data on their first and second wave cohorts and submitted aggregated data to the central site. Data quality control steps were adopted at the central site to correct for implausible values and harmonize units. Statistical analyses were performed by computing individual health care system effect sizes and synthesizing these using random effect meta-analyses to account for heterogeneity. We focused the laboratory analysis on C-reactive protein (CRP), ferritin, fibrinogen, procalcitonin, D-dimer, and creatinine based on their reported associations with severe COVID-19. RESULTS: Data were available for 79,613 patients, of which 32,467 were hospitalized in the first wave and 47,146 in the second wave. The prevalence of male patients and patients aged 50 to 69 years decreased significantly between the first and second waves. Patients hospitalized in the second wave had a 9.9% reduction in the risk of severe COVID-19 compared to patients hospitalized in the first wave (95% CI 8.5%-11.3%). Demographic subgroup analyses indicated that patients aged 26 to 49 years and 50 to 69 years; male and female patients; and black patients had significantly lower risk for severe disease in the second wave than in the first wave. At admission, the mean values of CRP were significantly lower in the second wave than in the first wave. On the seventh hospital day, the mean values of CRP, ferritin, fibrinogen, and procalcitonin were significantly lower in the second wave than in the first wave. In general, countries exhibited variable changes in laboratory testing rates from the first to the second wave. At admission, there was a significantly higher testing rate for D-dimer in France, Germany, and Spain. CONCLUSIONS: Patients hospitalized in the second wave were at significantly lower risk for severe COVID-19. This corresponded to mean laboratory values in the second wave that were more likely to be in typical physiological ranges on the seventh hospital day compared to the first wave. Our federated approach demonstrated the feasibility and power of harmonizing heterogeneous EHR data from multiple international health care systems to rapidly conduct large-scale studies to characterize how COVID-19 clinical trajectories evolve.