Assessing LSAM's ability to account for changes in organ donation and transplant center behavior.

The Liver Simulated Allocation Model (LSAM) is used to evaluate proposed organ allocation policies. Although LSAM has been shown to predict the directionality of changes in transplants and nonused organs, the magnitude is often overestimated. One reason is that policymakers and researchers using LSAM assume static levels of organ donation and center behavior because of challenges with predicting future behavior. We sought to assess the ability of LSAM to account for changes in organ donation and organ acceptance behavior using LSAM 2019. We ran 1-year simulations with the default model and then ran simulations changing donor arrival rates (ie, organ donation) and center acceptance behavior. Changing the donor arrival rate was associated with a progressive simulated increase in transplants, with corresponding simulated decreases in waitlist deaths. Changing parameters related to organ acceptance was associated with important changes in transplants, nonused organs, and waitlist deaths in the expected direction in data simulations, although to a much lesser degree than changing the donor arrival rate. Increasing the donor arrival rate was associated with a marked decrease in the travel distance of donor livers in simulations. In conclusion, we demonstrate that LSAM can account for changes in organ donation and organ acceptance in a manner aligned with historical precedent that can inform future policy analyses. As Scientific Registry of Transplant Recipients develops new simulation programs, the importance of considering changes in donation and center practice is critical to accurately estimate the impact of new allocation policies.

Comparison of electrogram characteristics in persistent atrial fibrillation.

INTRODUCTION: Multiple analysis techniques evaluate electrograms during atrial fibrillation (AF), but none have been established to guide catheter ablation. This study compares electrogram properties recorded from multiple right (RA) and left atrial (LA) sites. METHODS: Multisite LA/RA mapping (281 ± 176/239 ± 166 sites/patient) was performed in 42 patients (30 males, age 63 ± 9 years) undergoing first (n = 32) or redo-AF ablation (n = 10). All electrogram recordings were visually reviewed and artifactual signals were excluded leaving a total of 21 846 for analysis. Electrogram characteristics evaluated were cycle length (CL), amplitude, Shannon's entropy (ShEn), fractionation interval, dominant frequency, organizational index, and cycle length of most recurrent morphology (CLR ) from morphology recurrence plot analysis. RESULTS: Electrogram characteristics were correlated to each other. All pairwise comparisons were significant (p < .001) except for dominant frequency and CLR (p = .59), and amplitude and dominant frequency (p = .38). Only ShEn and fractionation interval demonstrated a strong negative correlation (r = -.94). All other pairwise comparisons were poor to moderately correlated. The relationships are highly conserved among patients, in the RA versus LA, and in those undergoing initial versus redo ablations. Antiarrhythmic drug therapy did not have a significant effect on electrogram characteristics, except minimum ShEn. Electrogram characteristics associated with ablation outcome were shorter minimum CLR , lower minimum ShEn, and longer mimimum CL. There was minimal overlap between the top 10 sites identified by one electrogram characteristic and the top 10 sites identified by the other 10 characteristics. CONCLUSION: Multiple techniques can be employed for electrogram analysis in AF. In this analysis of eight different electrogram characteristics, seven were poorly to moderately correlated and do not identify similar locations. Only some characteristics were predictive of ablation outcome. Further studies to consider electrogram properties, perhaps in combination, for categorizing and/or mapping AF are warranted.

Association between country of birth and gastric intestinal metaplasia: a retrospective cohort study.

Background: As a precursor to gastric cancer, gastric intestinal metaplasia (GIM) represents a target for surveillance. US-based guidelines recommend surveillance of racial/ethnic minorities and immigrants from high incidence gastric cancer regions, yet there is marked variability in prevalence amongst these subgroups and within groups from high incidence regions. There is a paucity of information regarding country of birth as a risk factor for GIM and we sought to determine the association between country of birth and GIM in an ethnically and racially diverse US population. Methods: This was a retrospective cohort study of persons who underwent esophagogastroduodenoscopy (EGD) with gastric biopsy at University of Miami Hospital between 2011 and 2021. A natural language processing (NLP) algorithm was developed and implemented to extract diagnoses of GIM and Helicobacter pylori (HP) infection from endoscopic pathology reports. Multivariable logistic regression was performed to evaluate risk factors for GIM, accounting for important covariates, including country of birth. Findings: A total of 21,108 persons from 130 varying countries of birth were included in the study. A total of 1699 cases of GIM were identified yielding a prevalence of 8.0% (95% CI: 7.7-8.4%). Multivariable analysis was restricted to countries with at least 100 persons in the cohort, yielding 15 countries with 1208 cases of GIM. Country of birth (p < 0.0001), race/ethnicity (p = 0.026), active HP infection (p < 0.0001), and increasing age (p < 0.0001) were significantly associated with increased odds of GIM. Highest odds for GIM were among persons born in Ecuador (OR 2.34, 95% CI 1.56-3.50), Honduras (OR 2.34, 95% CI 1.65-3.34), and Peru (OR 2.17, 95% CI 1.58-2.99). Interpretation: We demonstrate that country of birth is a key risk factor for GIM. Not all countries that are thought to be in "high-risk" regions are associated with higher rates of GIM, underlining the importance of studying the under-investigated risk factor of country of birth. Guidelines should account for country of birth, in addition to other risk factors, to tailor screening/surveillance appropriately. Funding: Shida Haghighat, MD, MPH is supported by an NIH training grant T32 DK 11667805.

Impact of Diabetes Mellitus on Benefit of ß-Blocker Therapy After Myocardial Infarction.

Beta blockers are uniformly recommended for all patients after myocardial infarction (MI), including those with diabetes mellitus (DM). This study assesses the impact of ß-blocker type and dosing on survival in patients with DM after MI. A cohort of 6,682 patients in the Outcomes of Beta-blocker Therapy After Myocardial INfarction registry were discharged after MI. In this cohort, 2,137 patients had DM (32%). Beta-blocker dose was indexed to the target daily dose used in randomized clinical trials and reported as percentage. Dosage groups were: no ß blocker, >0% to 12.5%, >12.5% to 25%, >25% to 50%, and >50% of the target dose. The overall mean discharge ß-blocker dose in patients with DM was 42.7 ± 34.1% versus 35.9 ± 27.4% in patients without DM (p <0.0001). Patients with DM were prescribed carvedilol at a higher rate than those without DM (27.8% vs 19.6%). The 3-year mortality estimates were 24.4% and 12.8% for patients with DM versus without DM (p <0.0001), respectively, with an unadjusted hazard ratio = 1.820 (confidence interval 1.587 to 2.086, p <0.0001). Patients with DM in the >12.5% to 25% dose category had the highest survival rates, whereas patients in the >50% dose had the lowest survival rate among patients discharged on ß blockers (p <0.0001). In the multivariable analysis among patients with DM after MI, all ß-blocker dose categories demonstrated lower mortality than no therapy; however, only the >12.5% to 25% dose had a statistically significant hazard ratio 0.450 (95% confidence interval 0.224 to 0.907, p = 0.025). In patients with DM, there was no statistically significant difference in 3-year mortality among those treated with metoprolol versus carvedilol. In conclusion, our analysis in patients with DM after MI suggested a survival benefit from ß-blocker therapy, with no apparent advantage to high- versus low-dose ß-blocker therapy; although, physicians tended to prescribe higher doses in patients with DM. There was no survival benefit for carvedilol over metoprolol in patients with DM.

Association Between Critical Events in the PICU and Outcomes in Neighboring Patients.

PICU patients who experience critical illness events, such as intubation, are at high risk for morbidity and mortality. Little is known about the impact of these events, which require significant resources, on outcomes in other patients. Therefore, we aimed to assess the association between critical events in PICU patients and the risk of similar events in neighboring patients over the next 6 hours. DESIGN: Retrospective observational cohort study. SETTING: Quaternary care PICU at the University of Chicago. PATIENTS: All children admitted to the PICU between 2012 and 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was a critical event defined as the initiation of invasive ventilation, initiating vasoactive medications, cardiac arrest, or death. The exposure was the occurrence of a critical event among other patients in the PICU within the preceding 6 hours. Discrete-time survival analysis using fixed 6-hour blocks beginning at the time of PICU admission was used to model the risk of experiencing a critical event in the PICU when an event occurred in the prior 6 hours. There were 13,628 admissions, of which 1,886 (14%) had a critical event. The initiation of mechanical ventilation was the most frequent event (n = 1585; 59%). In the fully adjusted analysis, there was a decreased risk of critical events (odds ratio, 0.82; 95% CI, 0.70-0.96) in the 6 hours following exposure to a critical event. This association was not present when considering longer intervals and was more pronounced in patients younger than 6 years old when compared with patients 7 years and older. CONCLUSION: Critical events in PICU patients are associated with decreased risk of similar events in neighboring patients. Further studies targeted toward exploring the mechanism behind this effect as well as identification of other nonpatient factors that adversely affect outcomes in children are warranted.