786 research outputs found

    A Constrained Maximum Likelihood Approach to Developing Well-Calibrated Models for Predicting Binary Outcomes.

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    The added value of candidate predictors for risk modeling is routinely evaluated by comparing the performance of models with or without including candidate predictors. Such comparison is most meaningful when the estimated risk by the two models are both unbiased in the target population. Very often data for candidate predictors are sourced from nonrepresentative convenience samples. Updating the base model using the study data without acknowledging the discrepancy between the underlying distribution of the study data and that in the target population can lead to biased risk estimates and therefore an unfair evaluation of candidate predictors. To address this issue assuming access to a well-calibrated base model, we propose a semiparametric method for model fitting that enforces good calibration. The central idea is to calibrate the fitted model against the base model by enforcing suitable constraints in maximizing the likelihood function. This approach enables unbiased assessment of model improvement offered by candidate predictors without requiring a representative sample from the target population, thus overcoming a significant practical challenge. We study theoretical properties for model parameter estimates, and demonstrate improvement in model calibration via extensive simulation studies. Finally, we apply the proposed method to data extracted from Penn Medicine Biobank to inform the added value of breast density for breast cancer risk assessment in the Caucasian woman population

    Genome-wide association study of breast density among women of African ancestry

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    Breast density, the amount of fibroglandular versus fatty tissue in the breast, is a strong breast cancer risk factor. Understanding genetic factors associated with breast density may help in clarifying mechanisms by which breast density increases cancer risk. To date, 50 genetic loci have been associated with breast density, however, these studies were performed among predominantly European ancestry populations. We utilized a cohort of women aged 40-85 years who underwent screening mammography and had genetic information available from the Penn Medicine BioBank to conduct a Genome-Wide Association Study (GWAS) of breast density among 1323 women of African ancestry. For each mammogram, the publicly available LIBRA software was used to quantify dense area and area percent density. We identified 34 significant loci associated with dense area and area percent density, with the strongest signals i

    External validation of a mammography-derived AI-based risk model in a U.S. breast cancer screening cohort of White and Black women

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    Despite the demonstrated potential of artificial intelligence (AI) in breast cancer risk assessment for personalizing screening recommendations, further validation is required regarding AI model bias and generalizability. We performed external validation on a U.S. screening cohort of a mammography-derived AI breast cancer risk model originally developed for European screening cohorts. We retrospectively identified 176 breast cancers with exams 3 months to 2 years prior to cancer diagnosis and a random sample of 4963 controls from women with at least one-year negative follow-up. A risk score for each woman was calculated via the AI risk model. Age-adjusted areas under the ROC curves (AUCs) were estimated for the entire cohort and separately for White and Black women. The Gail 5-year risk model was also evaluated for comparison. The overall AUC was 0.68 (95% CIs 0.64-0.72) for all women, 0.67 (0.61-0.72) for White women, and 0.70 (0.65-0.76) for Black women. The AI risk model significantly outperformed the Gail risk model for all wome

    Neuroanatomic Predictors to Prodromal Psychosis in Velocardiofacial Syndrome (22q11.2 Deletion Syndrome): A Longitudinal Study

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    Background: Up to 30% of young adults with velocardiofacial syndrome (VCFS; 22q11.2 deletion syndrome) develop schizophrenia or psychosis. Identifying the neuroanatomic trajectories that increase risk for psychosis in youth with this genetic disorder is of great interest. Methods: We acquired high-resolution anatomic MR images and measures of psychiatric function on 72 youth with VCFS, 26 unaffected siblings and 24 age-matched community controls at two timepoints, between late childhood (mean age, 11.9 years) and mid-adolescence (mean age, 15.1 years). Results: With the exception of cranial gray matter and orbitofrontal prefrontal cortex, neuroanatomic trajectories in youth with VCFS were comparable to unaffected siblings and community controls during this developmental window. However, in youth with VCFS, longitudinal decreases in the volumes of cranial gray and white matter, prefrontal cortex, mesial temporal lobe, and cerebellum were associated with increased combined prodromal symptoms at Time 2. In contrast, only decreases in temporal lobe gray matter volumes (p \u3c .002) and verbal IQ (p \u3c .002) predicted specifically to positive prodromal symptoms of psychosis at Time 2. Conclusions: These findings are in line with studies of non-VCFS individuals at risk for schizophrenia, and suggest that early decrements in temporal lobe gray matter may be predictive of increased risk of prodromal psychotic symptoms in youth with VCFS

    Provider beliefs in effectiveness and recommendations for primary HPV testing in 3 health-care systems

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    In 2018, the US Preventive Services Task Force endorsed primary human papillomavirus testing (pHPV) for cervical cancer screening. We aimed to describe providers\u27 beliefs about pHPV testing effectiveness and which screening approach they regularly recommend. We invited providers who performed 10 or more cervical cancer screens in 2019 in 3 healthcare systems that had not adopted pHPV testing: Kaiser Permanente Washington, Mass General Brigham, and Parkland Health; 53.7% (501/933) completed the survey between October and December 2020. Response distributions varied across modalities (P \u3c .001), with cytology alone or cotesting being more often viewed as somewhat or very effective for 30- to 65-year-olds compared with pHPV (cytology alone 94.1%, cotesting 96.1%, pHPV 66.0%). In 21- to 29-year-olds, the pattern was similar (cytology alone 92.2%, 64.7% cotesting, 50.8% pHPV). Most providers were either incorrect or unsure of the guideline-recommended screening interval for pHPV. Educational efforts are needed about the relative effectiveness and recommended use of pHPV to promote guideline-concordant care

    Coping with stressful events: a pre-post-test of a psycho-educational intervention for undergraduate nursing and midwifery students

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    Background: Knowledge of coping mechanisms is important for nursing and midwifery students to cope with stressful events during undergraduate education. Objectives: To evaluate the impact of a psycho-educational intervention “Coping with Stressful Events” with first year undergraduate nursing and midwifery students. Design: A quasi-experimental, one-group pre-post-test. Settings: One school of nursing/midwifery in one university in Ireland. Participants: A convenience sample of all first year undergraduate nursing and midwifery students (n = 197). Of these 166 completed the pretest and 138 students completed the post test. Methods: Using the COPE Inventory questionnaire (Carver et al., 1989) data was collected pre and post-delivery of the psycho-educational intervention “Coping with Stressful Events” by two research assistants. Data were analysed using the IBM SPSS Statistics version 22 (NY, USA). Results: Results demonstrated improved coping skills by students. There were statistically significant differences between pre and post intervention for some coping subscales. For example, the mean subscale scores were lower post-intervention for restraint and mental disengagement, and higher for use of emotional and instrumental social support indicating improved coping strategies. Conclusions: This intervention has the potential to influence undergraduate nursing and midwifery students coping skills during their first year of an undergraduate programme

    Racial and ethnic disparities in cervical cancer screening from three U.S. healthcare settings

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    INTRODUCTION: This study sought to characterize racial and ethnic disparities in cervical cancer screening and follow-up of abnormal findings across 3 U.S. healthcare settings. METHODS: Data were from 2016 to 2019 and were analyzed in 2022, reflecting sites within the Multi-level Optimization of the Cervical Cancer Screening Process in Diverse Settings & Populations Research Center, part of the Population-based Research to Optimize the Screening Process consortium, including a safety-net system in the southwestern U.S., a northwestern mixed-model system, and a northeastern integrated healthcare system. Screening uptake was evaluated among average-risk patients (i.e., no previous abnormalities) by race and ethnicity as captured in the electronic health record, using chi-square tests. Among patients with abnormal findings requiring follow-up, the proportion receiving colposcopy or biopsy within 6 months was reported. Multivariable regression was conducted to assess how clinical, socioeconomic, and structural characteristics mediate observed differences. RESULTS: Among 188,415 eligible patients, 62.8% received cervical cancer screening during the 3-year study period. Screening use was lower among non-Hispanic Black patients (53.2%) and higher among Hispanic (65.4%,) and Asian/Pacific Islander (66.5%) than among non-Hispanic White patients (63.5%, all p\u3c0.001). Most differences were explained by the distribution of patients across sites and differences in insurance. Hispanic patients remained more likely to screen after controlling for a variety of clinical and sociodemographic factors (risk ratio=1.14, CI=1.12, 1.16). Among those receiving any screening test, Black and Hispanic patients were more likely to receive Pap-only testing (versus receiving co-testing). Follow-up from abnormal results was low for all groups (72.5%) but highest among Hispanic participants (78.8%, p\u3c0.001). CONCLUSIONS: In a large cohort receiving care across 3 diverse healthcare settings, cervical cancer screening and follow-up were below 80% coverage targets. Lower screening for Black patients was attenuated by controlling for insurance and site of care, underscoring the role of systemic inequity. In addition, it is crucial to improve follow-up after abnormalities are identified, which was low for all populations

    Hallucinations Beyond Voices : A Conceptual Review of the Phenomenology of Altered Perception in Psychosis

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    Recent psychiatric research and treatment initiatives have tended to move away from traditional diagnostic categories and have focused instead on transdiagnostic phenomena, such as hallucinations. However, this emphasis on isolated experiences may artificially limit the definition of such phenomena and ignore the rich, complex, and dynamic changes occurring simultaneously in other domains of experience. This article reviews the literature on a range of experiential features associated with psychosis, with a focus on their relevance for hallucinations. Phenomenological research on changes in cognition, perception, selfhood and reality, temporality, interpersonal experience, and embodiment are discussed, along with their implications for traditional conceptualizations of hallucinations. We then discuss several phenomenological and neurocognitive theories, as well as the potential impact of trauma on these phenomena. Hallucinations are suggested to be an equifinal outcome of multiple genetic, neurocognitive, subjective, and social processes; by grouping them together under a single, operationalizable definition, meaningful differences in etiology and phenomenology may be ignored. It is suggested that future research efforts strive to incorporate a broader range of experiential alterations, potentially expanding on traditional definitions of hallucinations. Relevance for clinical practice, including emphasizing phenomenologically responsive techniques and developing targeted new therapies, is discussed
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