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Background: Creatinine-based estimated glomerular filtration rate (eGFR CRE ) may overestimate kidney function in patients with sarcopenia. While cystatin C-based eGFR (eGFR CYS ) is less affected by muscle mass, it may underestimate kidney function in patients with obesity. We sought to evaluate the relationship between body composition defined by computed tomography (CT) scans and discordance between creatinine, eGFR CRE and eGFR CYS in adult patients with cancer., Methods: This study is a cross-sectional study of consecutive adults with cancer with an abdominal CT scan performed within 90 days of simultaneous eGFR CRE and eGFR CYS measurements between May 2010 and January 2022. Muscle and adipose tissue cross-sectional areas were measured at the level of the third lumbar vertebral body using a validated deep-learning pipeline. CT-defined sarcopenia was defined using independent sex-specific cut-offs for skeletal muscle index (<39 cm 2 /m 2 for women and <55 cm 2 /m 2 for men). High adiposity was defined as the highest sex-specific quartile of the total (visceral plus subcutaneous) adiposity index in the cohort. The primary outcome was eGFR discordance, defined by eGFR CYS  > 30% lower than eGFR CRE ; the secondary outcome was eGFR CYS  > 50% lower than eGFR CRE . The odds of eGFR discordance were estimated using multivariable logistic regression modelling. Unadjusted spline regression was used to evaluate the relationship between skeletal muscle index and the difference between eGFR CYS and eGFR CRE ., Results: Of the 545 included patients (mean age 63 ± 14 years, 300 [55%] females, 440 [80.7%] non-Hispanic white), 320 (58.7%) met the criteria for CT-defined sarcopenia, and 136 (25%) had high adiposity. A total of 259 patients (48%) had >30% eGFR discordance, and 122 (22.4%) had >50% eGFR discordance. After adjustment for potential confounders, CT-defined sarcopenia and high adiposity were both associated with >30% eGFR discordance (adjusted odds ratio [aOR] 1.90, 95% confidence interval [CI] 1.12-3.24; aOR 2.01, 95% CI 1.15-3.52, respectively) and >50% eGFR discordance (aOR 2.34, 95% CI 1.21-4.51; aOR 2.23, 95% CI 1.19-4.17, respectively). A spline model demonstrated that as skeletal muscle index decreases, the predicted difference between eGFR CRE and eGFR CYS widens considerably., Conclusions: CT-defined sarcopenia and high adiposity are both independently associated with large eGFR discordance. Incorporating valuable information from body composition analysis derived from CT scans performed as a part of routine cancer care can impact the interpretation of GFR estimates., (© 2024 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by Wiley Periodicals LLC.)

Importance: School-associated SARS-CoV-2 transmission is described as uncommon, although the true transmission rate is unknown., Objective: To identify the SARS-CoV-2 secondary attack rate (SAR) in schools and factors associated with transmission., Design, Setting, and Participants: This cohort study examined the risk of school-based transmission of SARS-CoV-2 among kindergarten through grade 12 students and staff in 10 Massachusetts school districts during 2 periods: fall 2020/spring 2021 (F20/S21) and fall 2021 (F21). School staff collected data on SARS-CoV-2 index cases and school-based contacts, and SAR was defined as the proportion of contacts acquiring SARS-CoV-2 infection., Exposure: SARS-CoV-2., Main Outcomes and Measures: Potential factors associated with transmission, including grade level, masking, exposure location, vaccination history, and Social Vulnerability Index (SVI), were analyzed using univariable and multivariable logistic regression models., Results: For F20/S21, 8 school districts (70 schools, >33 000 students) were included and reported 435 index cases (151 staff, 216 students, and 68 missing role) with 1771 school-based contacts (278 staff, 1492 students, and 1 missing role). For F21, 5 districts (34 schools, >18 000 students) participated and reported 309 index cases (37 staff, 207 students, and 65 missing role) with 1673 school-based contacts (107 staff and 1566 students). The F20/S21 SAR was 2.2% (lower bound, 1.6%; upper bound, 26.7%), and the F21 SAR was 2.8% (lower bound, 2.6%; upper bound, 7.4%). In multivariable analysis, during F20/S21, masking was associated with a lower odds of transmission compared with not masking (odds radio [OR], 0.12; 95% CI, 0.04-0.40; P < .001). In F21, classroom exposure vs out-of-classroom exposure was associated with increased odds of transmission (OR, 2.47; 95% CI, 1.07-5.66; P = .02); a fully vaccinated vs unvaccinated contact was associated with a lower odds of transmission (OR, 0.04; 95% CI, 0.00-0.62; P < .001). In both periods, a higher SVI was associated with a greater odds of transmission., Conclusions and Relevance: In this study of Massachusetts schools, the SAR for SARS-CoV-2 among school-based contacts was low during 2 periods, and factors associated with transmission risk varied over time. These findings suggest that ongoing surveillance efforts may be essential to ensure that both targeted resources and mitigation practices remain optimal and relevant for disease prevention.