Benchmarking clinical risk prediction algorithms with ensemble machine learning for the noninvasive diagnosis of liver fibrosis in NAFLD.

BACKGROUND AND AIMS: Ensemble machine-learning methods, like the superlearner, combine multiple models into a single one to enhance predictive accuracy. Here we explore the potential of the superlearner as a benchmarking tool for clinical risk prediction, illustrating the approach to identifying significant liver fibrosis among patients with NAFLD. APPROACH AND RESULTS: We used 23 demographic/clinical variables to train superlearner(s) on data from the NASH-clinical research network observational study (n = 648) and validated models with data from the FLINT trial (n = 270) and National Health and Nutrition Examination Survey (NHANES) participants with NAFLD (n = 1244). Comparing the superlearner's performance to existing models (Fibrosis-4 [FIB-4], NAFLD fibrosis score, Forns, AST to Platelet Ratio Index [APRI], BARD, and Steatosis-Associated Fibrosis Estimator [SAFE]), it exhibited strong discriminative ability in the FLINT and NHANES validation sets, with AUCs of 0.79 (95% CI: 0.73-0.84) and 0.74 (95% CI: 0.68-0.79) respectively. CONCLUSIONS: Notably, the SAFE score performed similarly to the superlearner, both of which outperformed FIB-4, APRI, Forns, and BARD scores in the validation data sets. Surprisingly, the superlearner derived from 12 base models matched the performance of one with 90 base models. Overall, the superlearner, being the "best-in-class" machine-learning predictor, excelled in detecting fibrotic NASH, and this approach can be used to benchmark the performance of conventional clinical risk prediction models.

The effect of socioeconomic status on pediatric heart transplant outcomes at a single institution between 2013 and 2022.

BACKGROUND: Disparities in pediatric heart transplant outcomes based on socioeconomic status (SES) have been previously observed. However, there is a need to reevaluate these associations in contemporary settings with advancements in transplant therapies and increased awareness of health disparities. This retrospective study aims to investigate the relationship between SES and outcomes for pediatric heart transplant patients. METHODS: Data were collected through a chart review of 176 pediatric patients who underwent first orthotopic heart transplantation (OHT) at a single center from 2013 to 2021. The Area Deprivation Index (ADI), a composite score based on U.S. census data, was used to quantify SES. Cox proportional hazards models and generalized linear models were employed to analyze the association between SES and graft failure, rejection rates, and hospitalization rates. RESULTS: The analysis revealed no statistically significant differences in graft failure rates, rejection rates, or hospitalization rates between low-SES and high-SES pediatric heart transplant patients for our single-center study. CONCLUSION: There may be patient education, policies, and social resources that can help mitigate SES-based healthcare disparities. Additional multi-center research is needed to identify post-transplant care that promotes patient equity.

Evaluating the utility of multi-gene, multi-disease population-based panel testing accounting for uncertainty in penetrance estimates.

Panel germline testing allows for the efficient detection of deleterious variants for multiple conditions, but the benefits and harms of identifying these variants are not always well understood. We present a multi-gene, multi-disease aggregate utility formula that allows the user to consider adding or removing each gene in a panel based on variant frequency, estimated penetrances, and subjective disutilities for testing positive but not developing the disease and testing negative but developing the disease. We provide credible intervals for utility that reflect uncertainty in penetrance estimates. Rare, highly penetrant deleterious variants tend to contribute positive net utilities for a wide variety of user-specified disutilities, even when accounting for parameter estimation uncertainty. However, the clinical utility of deleterious variants with moderate, uncertain penetrance depends more on assumed disutilities. The decision to include a gene on a panel depends on variant frequency, penetrance, and subjective utilities and should account for uncertainties around these factors.

Nirmatrelvir-Ritonavir and Symptoms in Adults With Postacute Sequelae of SARS-CoV-2 Infection: The STOP-PASC Randomized Clinical Trial.

Importance: There is an urgent need to identify treatments for postacute sequelae of SARS-CoV-2 infection (PASC). Objective: To assess the efficacy of a 15-day course of nirmatrelvir-ritonavir in reducing the severity of select PASC symptoms. Design, Setting, and Participants: This was a 15-week blinded, placebo-controlled, randomized clinical trial conducted from November 2022 to September 2023 at Stanford University (California). The participants were adults with moderate to severe PASC symptoms of 3 months or longer duration. Interventions: Participants were randomized 2:1 to treatment with oral nirmatrelvir-ritonavir (NMV/r, 300 mg and 100 mg) or with placebo-ritonavir (PBO/r) twice daily for 15 days. Main Outcomes and Measures: Primary outcome was a pooled severity of 6 PASC symptoms (fatigue, brain fog, shortness of breath, body aches, gastrointestinal symptoms, and cardiovascular symptoms) based on a Likert scale score at 10 weeks. Secondary outcomes included symptom severity at different time points, symptom burden and relief, patient global measures, Patient-Reported Outcomes Measurement Information System (PROMIS) measures, orthostatic vital signs, and sit-to-stand test change from baseline. Results: Of the 155 participants (median [IQR] age, 43 [34-54] years; 92 [59%] females), 102 were randomized to the NMV/r group and 53 to the PBO/r group. Nearly all participants (n = 153) had received the primary series for COVID-19 vaccination. Mean (SD) time between index SARS-CoV-2 infection and randomization was 17.5 (9.1) months. There was no statistically significant difference in the model-derived severity outcome pooled across the 6 core symptoms at 10 weeks between the NMV/r and PBO/r groups. No statistically significant between-group differences were found at 10 weeks in the Patient Global Impression of Severity or Patient Global Impression of Change scores, summative symptom scores, and change from baseline to 10 weeks in PROMIS fatigue, dyspnea, cognitive function, and physical function measures. Adverse event rates were similar in NMV/r and PBO/r groups and mostly of low grade. Conclusions and Relevance: The results of this randomized clinical trial showed that a 15-day course of NMV/r in a population of patients with PASC was generally safe but did not demonstrate a significant benefit for improving select PASC symptoms in a mostly vaccinated cohort with protracted symptom duration. Further studies are needed to determine the role of antivirals in the treatment of PASC. Trial Registration: ClinicalTrials.gov Identifier: NCT05576662.

Barriers to Family Building Among Physicians and Medical Students.

Importance: Physicians and medical students who desire to build families face significant barriers due to the structure and culture of medicine. Objective: To understand the barriers and facilitators to family building for all people in medicine-not only individuals who can become pregnant-through an open-ended, qualitative analysis of survey responses. Design, Setting, and Participants: This qualitative study used a survey conducted in April and May 2021 with a broad sample of physicians and medical students. Participants were recruited through social media, targeting physician and medical student communities. Physicians (residents, fellows, and physicians in independent practice) and medical students of all gender identities and sexual orientations were included. Informed by a postpositivist approach, coding reliability thematic analysis was performed on 3 open-ended survey questions on family-building experiences (what they would do differently, what advice they have for others, and anything else they wished to share). Main Outcomes and Measures: Identified themes were mapped to the social-ecological model, a model used in public health to examine how a spectrum of factors is associated with health outcomes. Results: A total of 2025 people (1860 [92%] women; 299 [15%] Asian, 151 [8%] Black, and 1303 [64%] White; 1730 [85%] heterosexual; and 1200 [59%] physicians who had completed training) responded to at least 1 of 3 open-ended questions. Themes mapped to social-ecological model levels included: (1) cultural, eg, medical training being at odds with family building; (2) organizational, eg, lack of institutional support for the range of family-building routes; (3) interpersonal, eg, impact of social support on family building; and (4) individual, eg, socioeconomic status and other individual factors that facilitate or inhibit family building. Recommendations to improve family-building experiences include implementing family-building curricula at medical schools, providing adequate parental leave for all physicians and medical students who become parents, and providing insurance coverage for all family-building routes. Conclusions and Relevance: In this qualitative study of physicians and medical students, self-reported barriers to family building were identified at each level of the social-ecological model. Addressing these barriers is critical to creating a more equitable family-building environment for physicians and medical students.