RESUMO
PURPOSE: To determine whether students' self-reported race/ethnicity and sex were associated with grades earned in 7 core clerkships. A person-centered approach was used to group students based on observed clerkship grade patterns. Predictors of group membership and predictive bias by race/ethnicity and sex were investigated. METHOD: Using data from 6 medical student cohorts at Johns Hopkins University School of Medicine (JHUSOM), latent class analysis was used to classify students based on clerkship grades. Multinomial logistic regression was employed to investigate if preclerkship measures and student demographic characteristics predicted clerkship performance-level groups. Marginal effects for United States Medical Licensing Exam (USMLE) Step 1 scores were obtained to assess the predictive validity of the test on group membership by race/ethnicity and sex. Predictive bias was examined by comparing multinomial logistic regression prediction errors across racial/ethnic groups. RESULTS: Three clerkship performance-level groups emerged from the data: low, middle, and high. Significant predictors of group membership were race/ethnicity, sex, and USMLE Step 1 scores. Black or African American students were more likely (odds ratio [OR] = 4.26) to be low performers than White students. Black or African American (OR = 0.08) and Asian students (OR = 0.41) were less likely to be high performers than White students. Female students (OR = 2.51) were more likely to be high performers than male students. Patterns of prediction errors observed across racial/ethnic groups showed predictive bias when using USMLE Step 1 scores to predict clerkship performance-level groups. CONCLUSIONS: Disparities in clerkship grades associated with race/ethnicity were found among JHUSOM students, which persisted after controlling for USMLE Step 1 scores, sex, and other preclerkship performance measures. Differential predictive validity of USMLE Step 1 exam scores and systematic error predictions by race/ethnicity show predictive bias when using USMLE Step 1 scores to predict clerkship performance across racial/ethnic groups.
RESUMO
CD44 is an adhesion molecule implicated in the progression of human breast cancer. The purpose of this study was to describe CD44 antigen expression in canine mammary carcinomas and to evaluate its prognostic significance in relation to other clinico-pathological variables. A reduction in CD44 expression was significantly related to variables such as tumour size and adherence to underlying tissues but was not related to tumour location or to ulceration of the overlying skin. Complex (grade I) and anaplastic (grade III) carcinomas exhibited more intense expression of this antigen than did some tubulopapillary and most solid carcinomas (grade II). Although reduced CD44 expression was associated with infiltrative growth and vascular invasion in solid carcinomas, intense expression was also observed in anaplastic tumours. Although overall these findings suggest a role for this adhesion factor in canine mammary tumour development and progression, the complexity and apparently paradoxical nature of some of the findings currently limit the use of this immunohistochemical marker as a prognostic indicator.
