As of the middle of December 2020, SARS-CoV-2 had infected more than 70 million people and caused more than 1.6 million deaths worldwide.¹ SARS-CoV-2 can cause COVID-19, a condition characterized by pneumonia, hyperinflammation, hypoxemic respiratory failure, a prothrombotic state, cardiac dysfunction, substantial mortality, and persistent morbidity in some survivors. Few therapeutic interventions authorized by the US Food and Drug Administration are available, and vaccine deployment has been slow. Progress in COVID-19 research has been slowed by a lack of broad access to clinical data. Investigators in the United Kingdom² and Denmark^2,3 have performed person-level analytical analyses across their respective populations to inform health care delivery, medication decisions, and national interventions, but the US has not had this capacity. A large, multicenter, representative clinical data set has been desperately needed by US practitioners, scientists, health care systems, and policymakers to develop predictive and diagnostic computational tools and to inform critical decisions.

Background The majority of U.S. reports of COVID-19 clinical characteristics, disease course, and treatments are from single health systems or focused on one domain. Here we report the creation of the National COVID Cohort Collaborative (N3C), a centralized, harmonized, high-granularity electronic health record repository that is the largest, most representative U.S. cohort of COVID-19 cases and controls to date. This multi-center dataset supports robust evidence-based development of predictive and diagnostic tools and informs critical care and policy. Methods and Findings In a retrospective cohort study of 1,926,526 patients from 34 medical centers nationwide, we stratified patients using a World Health Organization COVID-19 severity scale and demographics; we then evaluated differences between groups over time using multivariable logistic regression. We established vital signs and laboratory values among COVID-19 patients with different severities, providing the foundation for predictive analytics. The cohort included 174,568 adults with severe acute respiratory syndrome associated with SARS-CoV-2 (PCR >99% or antigen <1%) as well as 1,133,848 adult patients that served as lab-negative controls. Among 32,472 hospitalized patients, mortality was 11.6% overall and decreased from 16.4% in March/April 2020 to 8.6% in September/October 2020 (p = 0.002 monthly trend). In a multivariable logistic regression model, age, male sex, liver disease, dementia, African-American and Asian race, and obesity were independently associated with higher clinical severity. To demonstrate the utility of the N3C cohort for analytics, we used machine learning (ML) to predict clinical severity and risk factors over time. Using 64 inputs available on the first hospital day, we predicted a severe clinical course (death, discharge to hospice, invasive ventilation, or extracorporeal membrane oxygenation) using random forest and XGBoost models (AUROC 0.86 and 0.87 respectively) that were stable over time. The most powerful predictors in these models are patient age and widely available vital sign and laboratory values. The established expected trajectories for many vital signs and laboratory values among patients with different clinical severities validates observations from smaller studies, and provides comprehensive insight into COVID-19 characterization in U.S. patients. Conclusions This is the first description of an ongoing longitudinal observational study of patients seen in diverse clinical settings and geographical regions and is the largest COVID-19 cohort in the United States. Such data are the foundation for ML models that can be the basis for generalizable clinical decision support tools. The N3C Data Enclave is unique in providing transparent, reproducible, easily shared, versioned, and fully auditable data and analytic provenance for national-scale patient-level EHR data. The N3C is built for intensive ML analyses by academic, industry, and citizen scientists internationally. Many observational correlations can inform trial designs and care guidelines for this new disease.

Hed cohorts from 46 sites in the United States. Patients aged 65 and older with hip fracture surgery between March 15 and December 31, 2020, were included. The main outcomes were 30-day all-cause mortality and all-cause mortality. Results: In this national study that included 3303 adults with hip fracture surgery, the 30-day mortality was 14.6% with COVID-19-positive versus 3.8% in COVID-19-negative, a notable difference. The all-cause mortality for hip fracture surgery was 27.0% in the COVID-19-positive group during the study period. Dicussion: We found higher incidence of all-cause mortality in patients with versus without diagnosis of COVID-19 after undergoing hip fracture surgery. The mortality in hip fracture surgery in this national analysis was lower than other local and regional reports. The medical community can use this information to guide the management of hip fracture patients with a diagnosis of COVID-19....

Objectives: The purpose of this study was to investigate the response in orthopedic surgery to the coronavirus disease 2019 (COVID-19) pandemic across the United States by surveying surgeons about their care setting, timing of restrictions on elective surgery, use of telehealth, and estimated economic impact. Methods: A survey was distributed via REDCap through state orthopedic organizations...

Latinos in the United States experience numerous alcohol-related health disparities. There is accumulating evidence that pre-immigration factors are associated with post-immigration alcohol use, but the explanation for health disparities remains unclear. The present study is a secondary analysis of data from the Recent Latino Immigrant Study (RLIS), the first community-based cohort study to examine the pre- to post-immigration alcohol use trajectories of young adult Latino immigrants during their initial years in the United States. Exploratory analysis and hierarchical multiple logistic regression were performed to assess associations between various pre- and post-immigration factors and alcohol misuse among young adult Latino immigrants early in the immigration process. Using an ecodevelopmental approach, we examined potential social and environmental determinants across multiple levels of influence associated with post-immigration alcohol misuse in this population. The study sample consisted of 474 young adult Latino immigrants between the ages of 18–34. The sample was comprised of the following national/regional origins: Cuban (43%), South American (28.7%), and Central American (28.3%). Approximately half of the sample (49.6%) reported a family history of substance use problems (FHSUP+). Participants who reported FHSUP+ and who engaged in alcohol misuse prior to immigrating to the US were more likely to engage in post-immigration alcohol misuse. Results revealed various social and environmental factors associated with pre-immigration alcohol misuse in this population. Study findings can inform culturally tailored prevention interventions aimed at mitigating problem drinking behaviors among young adult recent Latino immigrants.

Objective: To assess ballistic femoral shaft fracture outcomes in comparison with closed and open femoral shaft fractures sustained by blunt mechanisms. We hypothesized that ballistic femoral shaft fractures would have similar outcomes to blunt open fractures. Design: Retrospective cohort study. Setting: Academic Level I trauma center. Participants: Patients 16 years and older presenting with ballistic (140), blunt closed (317), or blunt open (71) femoral shaft fractures. Main Outcomes: Unplanned return to operating room, fracture-related infection, soft tissue reconstruction, nonunion, implant failure, length of stay, Injury Severity Scores, hospital charges, and compartment syndrome. Results: A total of 528 femoral shaft fractures were identified. A group of 140 ballistic fractures and comparison groups of all femoral shaft fractures sustained by blunt mechanisms and treated with intramedullary nailing were included in the analysis. Among the 2 subgroups of nonballistic injuries, 317 were blunt closed fractures and 71 were blunt open fractures. The ballistic group was associated with a 3-fold increase in overall complications (30%) compared with the blunt closed group (10%, P < 0.001), had a higher occurrence of thigh compartment syndrome (P < 0.001), and required more soft tissue reconstruction (P < 0.001) than either of the blunt fracture groups. Conclusions: Ballistic femoral shaft fractures do not perfectly fit with blunt closed or open femoral fractures. A high index of suspicion for the development of thigh compartment syndrome should be maintained in ballistic femoral shaft fractures. The overall rates of nonunion and infection were comparable between all groups, but the all-cause complication rate was significantly higher in the ballistic group compared with the blunt closed group. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.