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Background: We developed a machine learning (ML) model that predicts the risk of a patient on hemodialysis (HD) having an undetected SARS-CoV-2 infection that is identified after the following ≥3 days., Methods: As part of a healthcare operations effort, we used patient data from a national network of dialysis clinics (February-September 2020) to develop an ML model (XGBoost) that uses 81 variables to predict the likelihood of an adult patient on HD having an undetected SARS-CoV-2 infection that is identified in the subsequent ≥3 days. We used a 60%:20%:20% randomized split of COVID-19-positive samples for the training, validation, and testing datasets., Results: We used a select cohort of 40,490 patients on HD to build the ML model (11,166 patients who were COVID-19 positive and 29,324 patients who were unaffected controls). The prevalence of COVID-19 in the cohort (28% COVID-19 positive) was by design higher than the HD population. The prevalence of COVID-19 was set to 10% in the testing dataset to estimate the prevalence observed in the national HD population. The threshold for classifying observations as positive or negative was set at 0.80 to minimize false positives. Precision for the model was 0.52, the recall was 0.07, and the lift was 5.3 in the testing dataset. Area under the receiver operating characteristic curve (AUROC) and area under the precision-recall curve (AUPRC) for the model was 0.68 and 0.24 in the testing dataset, respectively. Top predictors of a patient on HD having a SARS-CoV-2 infection were the change in interdialytic weight gain from the previous month, mean pre-HD body temperature in the prior week, and the change in post-HD heart rate from the previous month., Conclusions: The developed ML model appears suitable for predicting patients on HD at risk of having COVID-19 at least 3 days before there would be a clinical suspicion of the disease., Competing Interests: C. Monaghan, F. Maddux, H. Han, J. Larkin, L. Usvyat, S. Chaudhuri, and Y. Jiao are employees of Fresenius Medical Care in the Global Medical Office. E. Weinhandl, I. Dahne-Steuber, J. Hymes, K. Belmonte, K. Bermudez, and R. Kossmann are employees of Fresenius Medical Care North America. F. Maddux has directorships in the Fresenius Medical Care Management Board, Goldfinch Bio, and Vifor Fresenius Medical Care Renal Pharma. F. Maddux, I. Dahne-Steuber, J. Hymes, K. Belmonte, L. Usvyat, P. Kotanko, and R. Kossmann have share options/ownership in Fresenius Medical Care. L. Neri is an employee of Fresenius Medical Care Deutschland GmbH in the Europe, the Middle East, and Africa Medical Office. P. Kotanko is an employee of Renal Research Institute, a wholly owned subsidiary of Fresenius Medical Care; reports receiving honorarium from Up-To-Date; and is on the Editorial Board of Blood Purification and Kidney and Blood Pressure Research. All remaining authors have nothing to disclose., (Copyright © 2021 by the American Society of Nephrology.)

Objectives: To compare the long-term venous function of ligated, simple, and complex repairs and to assess long-term patency in repaired veins., Design: A cohort study of patients with lower-extremity venous injuries treated during a 7-year period., Setting: A level I urban trauma center., Patients: Twenty-one of the 79 patients with a history of lower-extremity venous injury identified via the trauma registry consented to outpatient evaluation., Intervention: Participating patients underwent a through vascular examination that included color flow duplex venous imaging and air plethysmographic assessment., Main Outcome Measures: The patency of venous repairs, the incidence of chronic deep venous thrombosis, and evidence of chronic venous insufficiency., Results: The venous injuries included 5 iliac, 10 femoral, and 6 popliteal. Six of these injuries were ligated, 11 injuries were simply repaired (lateral venorrhaphy or end-to-end), and 4 were repaired with complex interposition grafts. All repairs were patent, with no evidence of deep venous thrombosis by color flow duplex venous imaging. Seventeen of the 21 patients had symptoms, color flow duplex venous imaging findings, and air plethysmographic data consistent with chronic venous insufficiency, including significant mean differences (P < .03) in outflow fraction, outflow fraction with compression, venous filling index, and residual volume fraction, when compared with the uninjured extremity. The most profound changes followed complex repairs and perioperative fasciotomies., Conclusions: While the long-term patency of venous repairs is excellent, most patients demonstrate evidence of chronic venous insufficiency after either ligation or repair. Complex venous repairs and fasciotomy are associated with the most severe functional changes.