RESUMEN

BACKGROUND: Thirty-day hospital readmissions are a quality metric for health care systems. Predictive models aim to identify patients likely to readmit to more effectively target preventive strategies. Many risk of readmission models have been developed on retrospective data, but prospective validation of readmission models is rare. To the best of our knowledge, none of these developed models have been evaluated or prospectively validated in a military hospital. OBJECTIVES: The objectives of this study are to demonstrate the development and prospective validation of machine learning (ML) risk of readmission models to be utilized by clinical staff at a military medical facility and demonstrate the collaboration between the U.S. Department of Defense's integrated health care system and a private company. METHODS: We evaluated multiple ML algorithms to develop a predictive model for 30-day readmissions using data from a retrospective cohort of all-cause inpatient readmissions at Madigan Army Medical Center (MAMC). This predictive model was then validated on prospective MAMC patient data. Precision, recall, accuracy, and the area under the receiver operating characteristic curve (AUC) were used to evaluate model performance. The model was revised, retrained, and rescored on additional retrospective MAMC data after the prospective model's initial performance was evaluated. RESULTS: Within the initial retrospective cohort, which included 32,659 patient encounters, the model achieved an AUC of 0.68. During prospective scoring, 1,574 patients were scored, of whom 152 were readmitted within 30 days of discharge, with an all-cause readmission rate of 9.7%. The AUC of the prospective predictive model was 0.64. The model achieved an AUC of 0.76 after revision and addition of further retrospective data. CONCLUSION: This work reflects significant collaborative efforts required to operationalize ML models in a complex clinical environment such as that seen in an integrated health care system and the importance of prospective model validation.

Asunto(s)

RESUMEN

Perceived weight stigma is associated with adverse health indices, such as elevated cortisol, lipid/glucose dysregulation, and poorer self-rated health. This relationship may be particularly relevant for military personnel, given the cultural emphasis on fitness and weight/shape. Therefore, we investigated the relationship between weight stigma and physical health in 117 active duty personnel (66.7% male; 56.4% non-Hispanic White; age: 30.8 ± 7.4 years; BMI: 29.5 ± 2.5 kg/m2). Participants reported weight stigma (general and military-specific), weight bias internalization, and the presence (≥1; n = 55) or absence (n = 62) of medical conditions. Logistic regressions were conducted examining the ability of weight stigma (general or military-specific) and weight bias internalization to predict the presence or absence of medical conditions. General weight stigma was not significantly associated with the presence of a medical condition (p > .05). However, individuals with military-specific weight stigma scores twice that of their peers were over three times more likely (p = .04) to report a medical condition. Weight bias internalization was not significant in any model (ps > .20). Longitudinal studies should prospectively examine the relationship between weight stigma in the military setting and health among service members.

Asunto(s)

RESUMEN

Parallel to rising obesity rates is an increase in costs associated with excess weight. Estimates of future direct (medical) and indirect (nonmedical) costs related to obesity suggest rising expenditures that will impose a significant economic burden to individuals and society as a whole. This article reviews research on direct and indirect medical costs and future economic trends associated with obesity and associated comorbidities. Cost disparities associated with subsets of the population experiencing higher than average rates of obesity are explored. Finally, potential solutions with the highest estimated impact are offered, and future directions are proposed.

Asunto(s)

RESUMEN

OBJECTIVE: Limited data suggest that the children of U.S. service members may be at increased risk for disordered-eating. To date, no study has directly compared adolescent military-dependents to their civilian peers along measures of eating pathology and associated correlates. We, therefore, compared overweight and obese adolescent female military-dependents to their civilian counterparts along measures of eating-related pathology and psychosocial functioning. METHOD: Adolescent females with a BMI between the 85th and 97th percentiles and who reported loss-of-control eating completed interview and questionnaire assessments of eating-related and general psychopathology. RESULTS: Twenty-three military-dependents and 105 civilians participated. Controlling for age, race, and BMI-z, military-dependents reported significantly more binge episodes per month (p < 0.01), as well as greater eating-concern, shape-concern, and weight-concern (p's < 0.01) than civilians. Military-dependents also reported more severe depression (p < 0.05). DISCUSSION: Adolescent female military-dependents may be particularly vulnerable to disordered-eating compared with civilian peers. This potential vulnerability should be considered when assessing military-dependents.

Asunto(s)

RESUMEN

Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N = 761, 58% females, ages 18-81 years; 41.3 ± 14.5) from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity [(body mass index (BMI; kg/m(2)) and waist circumference (WC; in)] and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy). Whole-brain average and regional fractional anisotropy values for 10 major white matter tracts were calculated from high angular resolution diffusion tensor imaging data (DTI; 1.7 × 1.7 × 3 mm; 55 directions). Additive genetic factors explained intersubject variance in BMI (heritability, h (2) = 0.58), WC (h (2) = 0.57), and FA (h (2) = 0.49). FA shared significant portions of genetic variance with BMI in the genu (ρG = -0.25), body (ρG = -0.30), and splenium (ρG = -0.26) of the corpus callosum, internal capsule (ρG = -0.29), and thalamic radiation (ρG = -0.31) (all p's = 0.043). The strongest evidence of shared variance was between BMI/WC and FA in the superior fronto-occipital fasciculus (ρG = -0.39, p = 0.020; ρG = -0.39, p = 0.030), which highlights region-specific variation in neural correlates of obesity. This may suggest that increase in obesity and reduced white matter integrity share common genetic risk factors.

RESUMEN

Obesity impacts the U.S. military by affecting the health and readiness of active duty service members and their families. Preventing Obesity in Military Communities (POMC) is a comprehensive research program within Patient Centered Medical Homes (PCMHs) in three Military Training Facilities. This paper describes three pilot randomized controlled trials that target critical high risk periods for unhealthy weight gain from birth to young adulthood: (1) pregnancy and early infancy (POMC-Mother-Baby), (2) adolescence (POMC-Adolescent), and (3) the first tour of duty after boot camp (POMC-Early Career). Each study employs a two-group randomized treatment or prevention program with follow up. POMC offers a unique opportunity to bring together research and clinical expertise in obesity prevention to develop state-of-the-art programs within PCMHs in Military Training Facilities. This research builds on existing infrastructure that is expected to have immediate clinical benefits to DoD and far-reaching potential for ongoing collaborative work. POMC may offer an economical approach for widespread obesity prevention, from conception to young adulthood, in the U.S. military as well as in civilian communities.

Asunto(s)

RESUMEN

PURPOSE: The purpose of this study was to determine the reproducibility of a very short echo time (TE) phase rotation stimulated echo acquisition mode (STEAM) sequence at 3T with a focus on the detection of glutathione. METHODS: Ten healthy subjects were scanned on two separate visits. Spectra were acquired from voxels placed in the anterior and posterior cingulates. Reproducibility was assessed using mean coefficients of variation (CVs) and mean absolute differences (ADs), and reliability was assessed using standard error of measurement (SEM) and intraclass correlations (ICCs). Phantoms containing glutathione and metabolites with overlapping resonances were scanned to test the validity of glutathione quantification. RESULTS: Excellent reproducibility as illustrated by CVs ≤8.3% and ADs ≤11.6% for both regions was obtained for glutathione and other commonly reported metabolites. Reproducibility measures for γ-aminobutyric acid and glutamine were good overall with CVs ranging from 6.4%-10.5% and ADs ranging from 8.6%-15.5% for both regions. Glutathione absolute and relative reliability were very good (SEMs ≤9.9%) and fair (ICCs = 0.42-0.51), respectively. Phantom studies demonstrated the ability to accurately detect glutathione from other metabolites with overlapping resonances with great precision (R(2) = 0.99). CONCLUSION: A very short TE phase rotation STEAM sequence proved reproducible for metabolites difficult to quantify but important for the study of psychiatric and neurological illness.

Asunto(s)

RESUMEN

Abnormal hippocampal function likely contributes to relational learning deficits observed in schizophrenia. It is unknown whether these deficits can be attenuated with a training intervention. The purpose of this project was to determine if training could facilitate relational learning of the transverse patterning task in schizophrenia. Healthy and schizophrenia subjects completed a version of transverse patterning that incorporated training. The majority of subjects with schizophrenia successfully learned transverse patterning when provided with training. A subgroup (approximately 25%) of schizophrenia subjects showed no tendency to learn with training. These results were replicated in a second study with a separate cohort and different stimuli. This study illustrates that relational learning of the transverse patterning can be facilitated in schizophrenia with training.

RESUMEN

Learning and memory impairments are present in schizophrenia (SZ) throughout the illness course and predict psychosocial function. Abnormalities in prefrontal and hippocampal function are thought to contribute to SZ deficits. The radial arm maze (RAM) is a test of spatial learning and memory in rodents that relies on intact prefrontal and hippocampal function. The goal of the present study was to investigate spatial learning in SZ using a virtual RAM. Thirty-three subjects with SZ and thirty-nine healthy controls (HC) performed ten trials of a virtual RAM task. Subjects attempted to learn to retrieve four rewards each located in separate arms. As expected, subjects with SZ used more time and traveled more distance to retrieve rewards, made more reference (RM) and working memory (WM) errors, and retrieved fewer rewards than HC. It is important to note that the SZ group did learn but did not reach the level of HC. Whereas RM errors decreased across trials in the SZ group, WM errors did not. There were no significant relationships between psychiatric symptom severity and maze performance. To our knowledge, use of a virtual 8-arm radial maze task in SZ to assess spatial learning is novel. Impaired virtual RAM performance in SZ is consistent with studies that examined RAM performance in animal models of SZ. Results provide further support for compromised prefrontal and hippocampal function underlying WM and RM deficits in SZ. The virtual RAM task could help bridge preclinical and clinical research for testing novel drug treatments of SZ.

Asunto(s)

Asunto(s)

RESUMEN

Relational learning, which is learning the relationship among items, is impaired in schizophrenia but can be improved with training. This study investigated neural changes with functional magnetic resonance imaging before and after training on a relational learning task in schizophrenia and healthy control subjects. Despite their acquiring similar relational learning performance, the groups exhibited different neural activation patterns before and following training. Controls engaged regions within the relational learning network that included frontal, parietal, and medial temporal lobe, before and following training. Controls also exhibited activation reductions in region and spatial extent with relational learning proficiency, a commonly observed phenomenon in successful learning. In contrast, subjects with schizophrenia displayed no positive activations compared with the control condition before training. After training, subjects with schizophrenia displayed bilateral inferior parietal region activation as predicted. Contrary to hypothesis, hippocampal activation was not observed following training in schizophrenia. These findings suggest that the parietal lobe may be receptive to cognitive training interventions and that successful relational learning may be achieved in schizophrenia through the use of alternative extrahippocampal brain regions.

Asunto(s)

RESUMEN

Schizophrenia can be classified into two separate syndromes: deficit and nondeficit. Primary, enduring negative symptoms are used to define the deficit form of the illness, which is believed to have a unique neurobiological substrate. Previous research suggests that an aberrant prefrontal-thalamic-parietal network underlies deficit schizophrenia. In this study we conducted diffusion tensor imaging (DTI) fiber tracking to assess the integrity of the superior longitudinal fasciculus (SLF), the major white matter tract that connects prefrontal and parietal cortical regions, in deficit and nondeficit people with schizophrenia. We also used proton magnetic resonance spectroscopy (1H-MRS) to assess neurochemistry in the left middle prefrontal and left inferior parietal cortical regions. A total of 20 subjects with schizophrenia (10 deficit and 10 nondeficit) and 11 healthy subjects participated in this study. Results revealed reduced fractional anisotropy (FA), an index of white matter integrity, in the right hemisphere SLF and frontal white matter in the deficit subjects. There were no differences in MRS metabolite concentrations among groups. To our knowledge, this is the first DTI study to show compromised integrity of the major white matter tract that connects frontal and parietal regions in deficit schizophrenia. These findings provide further support for altered frontal-parietal network in deficit schizophrenia.

Asunto(s)