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Source and raw water quality may deteriorate due to rainfall and river flow events that occur in watersheds. The effects on raw water quality are normally detected in drinking water treatment plants (DWTPs) with a time-lag after these events in the watersheds. Early warning systems (EWSs) in DWTPs require models with high accuracy in order to anticipate changes in raw water quality parameters. Ensemble machine learning (EML) techniques have recently been used for water quality modeling to improve accuracy and decrease variance in the outcomes. We used three decision-tree-based EML models (random forest [RF], gradient boosting [GB], and eXtreme Gradient Boosting [XGB]) to predict two critical parameters for DWTPs, raw water Turbidity and UV absorbance (UV254), using rainfall and river flow time series as predictors. When modeling raw water turbidity, the three EML models (r RF-Tu 2 =0.87, r GB-Tu 2 =0.80 and r XGB-Tu 2 =0.81) showed very good performance metrics. For raw water UV254, the three models (r RF-UV 2 =0.89, r GB-UV 2 =0.85 and r XGB-UV 2 =0.88) again showed very good performance metrics. Results from this study suggest that EML approaches could be used in EWSs to anticipate changes in the quality parameters of raw water and enhance decision-making in DWTPs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Christian Ortiz-Lopez reports financial support was provided by Natural Sciences and Engineering Research Council of Canada (NSERC). If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: There is increasing emphasis on resident involvement in quality improvement (QI) efforts, yet resident engagement in QI has remained low for many reasons. Although QI methods are classically applied to clinical processes, there are many opportunities to incorporate QI principles into curricular design and implementation., Objective: Demonstrate the utility of QI methods when applied to curricular design and the implementation of a novel point-of-care ultrasound portfolio development and quality assurance program at a large internal medicine residency program., Methods: We applied foundational QI methods, including process mapping, plan-do-study-act (PDSA) cycles, time-trap identification, run-chart analysis, and qualitative interviews throughout the curricular design and implementation phases to rapidly identify areas for improvement and perform timely tests of change., Results: Fifty-one interns participated in the curriculum, submitting 731 images in the first trimester. Process mapping and submission review revealed that 29% of images were saved to the incorrect digital archive. Resident-reviewer interpretation concordance was present in 80.7% of submissions. In 95.2% of completed quality assurance cards, the same information was provided in the commentary feedback and the evaluator's checklists, representing a time trap. Interventions included restricting access to image archives and removing redundant fields from quality assurance cards. The time to feedback fell from 69.5 to 6.5 days, demonstrating nonrandom variation via run-chart analysis., Conclusion: This pilot study demonstrates the successful application of QI methods to a novel point-of-care ultrasound curriculum. The systematic use of these methodologies in curricular design and implementation allows expeditious curricular improvement. Emphasizing the relevance of QI methods to subject matter beyond clinical processes may increase resident engagement in QI efforts., (Copyright © 2023 by the American Thoracic Society.)

Background: Lung ultrasound (LUS) is a clinician-performed evidence-based imaging modality that has multiple advantages in the evaluation of dyspnea caused by multiple disease processes, including COVID-19. Despite these advantages, few hospitalists have been trained to perform LUS. The aim of this study was to increase adoption and implementation of LUS during the 2020 COVID-19 pandemic by using recurrent assessments of RE-AIM outcomes to iteratively revise our implementation strategies., Methods: In an academic hospital, we implemented guidelines for the use of LUS in patients with COVID-19 in July 2020. Using a novel "RE-AIM dashboard," we used an iterative process of evaluating the high-priority outcomes of Reach, Adoption, and Implementation at twice monthly intervals to inform revisions of our implementation strategies for LUS delivery (i.e., Iterative RE-AIM process). Using a convergent mixed methods design, we integrated quantitative RE-AIM outcomes with qualitative hospitalist interview data to understand the dynamic determinants of LUS Reach, Adoption, and Implementation., Results: Over the 1-year study period, 453 LUSs were performed in 298 of 12,567 eligible inpatients with COVID-19 (Reach = 2%). These 453 LUS were ordered by 43 out of 86 eligible hospitalists (LUS order adoption = 50%). However, the LUSs were performed/supervised by only 8 of these 86 hospitalists, 4 of whom were required to complete LUS credentialing as members of the hospitalist procedure service (proceduralist adoption 75% vs 1.2% non-procedural hospitalists adoption). Qualitative and quantitative data obtained to evaluate this Iterative RE-AIM process led to the deployment of six sequential implementation strategies and 3 key findings including (1) there were COVID-19-specific barriers to LUS adoption, (2) hospitalists were more willing to learn to make clinical decisions using LUS images than obtain the images themselves, and (3) mandating the credentialing of a strategically selected sub-group may be a successful strategy for improving Reach., Conclusions: Mandating use of a strategically selected subset of clinicians may be an effective strategy for improving Reach of LUS. Additionally, use of Iterative RE-AIM allowed for timely adjustments to implementation strategies, facilitating higher levels of LUS Adoption and Reach. Future studies should explore the replicability of these preliminary findings., (© 2022. The Author(s).)

Acute decompensated heart failure is the leading admitting diagnosis in patients 65 years and older with more than 1 million hospitalizations per year in the US alone. Traditional tools to evaluate for and monitor volume status in patients with heart failure, including symptoms and physical exam findings, are known to have limited accuracy. In contrast, point of care lung ultrasound is a practical and evidenced-based tool for monitoring of volume status in patients with heart failure. However, few inpatient clinicians currently use this tool to monitor diuresis. We performed semi-structured interviews of 23 hospitalists practicing in five geographically diverse academic institutions in the US to better understand how hospitalists currently assess and monitor volume status in patients hospitalized with heart failure. We also explored their perceptions and attitudes toward adoption of lung ultrasound. Hospitalist participants reported poor reliability and confidence in the accuracy of traditional tools to monitor diuresis and expressed interest in learning or were already using lung ultrasound for this purpose. The time required for training and access to equipment that does not impede workflow were considered important barriers to its adoption by interviewees., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2020, Maw et al.)

Background: The metabolic defects of nonalcoholic steatohepatitis (NASH) and prediabetes or type 2 diabetes mellitus (T2DM) seem to be specifically targeted by pioglitazone. However, information about its long-term use in this population is limited., Objective: To determine the efficacy and safety of long-term pioglitazone treatment in patients with NASH and prediabetes or T2DM., Design: Randomized, double-blind, placebo-controlled trial. (ClinicalTrials.gov: NCT00994682)., Setting: University hospital., Participants: Patients (n = 101) with prediabetes or T2DM and biopsy-proven NASH were recruited from the general population and outpatient clinics., Intervention: All patients were prescribed a hypocaloric diet (500-kcal/d deficit from weight-maintaining caloric intake) and then randomly assigned to pioglitazone, 45 mg/d, or placebo for 18 months, followed by an 18-month open-label phase with pioglitazone treatment., Measurements: The primary outcome was a reduction of at least 2 points in the nonalcoholic fatty liver disease activity score in 2 histologic categories without worsening of fibrosis. Secondary outcomes included other histologic outcomes, hepatic triglyceride content measured by magnetic resonance and proton spectroscopy, and metabolic parameters., Results: Among patients randomly assigned to pioglitazone, 58% achieved the primary outcome (treatment difference, 41 percentage points [95% CI, 23 to 59 percentage points]) and 51% had resolution of NASH (treatment difference, 32 percentage points [CI, 13 to 51 percentage points]) (P < 0.001 for each). Pioglitazone treatment also was associated with improvement in individual histologic scores, including the fibrosis score (treatment difference, -0.5 [CI, -0.9 to 0.0]; P = 0.039); reduced hepatic triglyceride content from 19% to 7% (treatment difference, -7 percentage points [CI, -10 to -4 percentage points]; P < 0.001); and improved adipose tissue, hepatic, and muscle insulin sensitivity (P < 0.001 vs. placebo for all). All 18-month metabolic and histologic improvements persisted over 36 months of therapy. The overall rate of adverse events did not differ between groups, although weight gain was greater with pioglitazone (2.5 kg vs. placebo)., Limitation: Single-center study., Conclusion: Long-term pioglitazone treatment is safe and effective in patients with prediabetes or T2DM and NASH., Primary Funding Source: Burroughs Wellcome Fund and American Diabetes Association.

Introduction: Radiographic contrast administration is a major cause of acute kidney injury (AKI), worldwide. Currently, contrast induced acute kidney injury (CI-AKI) is the third leading cause of hospital acquired renal failure in the United States. Over 50% of these cases are the result of contrast exposure during cardiac catheterization. The predictive risk factors for and clinical impact of AKI following coronary procedures have been extensively studied and documented in the literature. Similar data, however, are lacking for AKI following angiography or endovascular interventions for lower extremity peripheral artery disease (PAD)., Methods: The present review examined the published data available for AKI in patients undergoing peripheral procedures using MEDLINE searches. Specific data on number of peripheral cases, subject characteristics, hydration strategies, and AKI incidence rates was recorded., Results: The systematic review resulted in 50 potentially relevant studies and ultimately 15 studies were selected for detailed analysis that included AKI incidence data on patients undergoing peripheral angiography or interventions. The summated studies included 11,311 patients and 10,316 peripheral procedures. The median incidence of AKI in the studies was 10%. The retrieved publications demonstrated significant variations in patient risk factors, definitions of AKI, and specificity of description of endovascular therapies., Conclusions: The incidence, risk factors, and outcomes related to AKI in the context of peripheral angiography or endovascular therapy remain poorly described in the literature and warrant further study in a prospective, systematic fashion. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Objective: Nonalcoholic steatohepatitis (NASH) is increasingly common in obese patients. However, its metabolic consequences in patients with type 2 diabetes mellitus (T2DM) are unknown., Research Design and Methods: We studied 154 obese patients divided in four groups: 1) control (no T2DM or NAFLD), 2) T2DM without NAFLD, 3) T2DM with isolated steatosis, and 4) T2DM with NASH. We evaluated intrahepatic triglycerides by proton MRS ((1)H-MRS) and assessed insulin secretion/resistance during an oral glucose tolerance test and a euglycemic-hyperinsulinemic clamp with glucose turnover measurements., Results: No significant differences among groups were observed in sex, BMI, or total body fat. Metabolic parameters worsened progressively with the presence of T2DM and the development of hepatic steatosis, with worse hyperinsulinemia, insulin resistance, and dyslipidemia (hypertriglyceridemia and low HDL cholesterol) in those with NASH (P < 0.001). Compared with isolated steatosis, NASH was associated with more dysfunctional and insulin-resistant adipose tissue (either as insulin suppression of plasma FFA [33 ± 3 vs. 48 ± 6%] or adipose tissue insulin resistance index [9.8 ± 1.0 vs. 5.9 ± 0.8 mmol/L ⋅ µIU/mL]; both P < 0.03). Furthermore, insulin suppression of plasma FFA correlated well with hepatic steatosis (r = -0.62; P < 0.001) and severity of steatohepatitis (rs = -0.52; P < 0.001). Hepatic insulin sensitivity was also more significantly impaired among patients with T2DM and NASH, both fasting and with increasing insulin levels within the physiological range (10 to 140 µIU/mL), compared with other groups., Conclusions: In obese patients with T2DM, the presence of NAFLD is associated with more severe hyperinsulinemia, dyslipidemia, and adipose tissue/hepatic insulin resistance compared with patients without NAFLD. The unfavorable metabolic profile linked to NAFLD should prompt strategies to identify and treat this population early on., (© 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.)

Background: The AVERT(TM) Contrast Modulation System (AVERT) (Osprey Medical, MN) is designed to reduce contrast volume administration during angiography. The AVERT provides an adjustable resistance circuit which decreases the pressure head delivering contrast towards the patient. The AVERT has not been previously studied in patients undergoing peripheral digital subtraction angiography (DSA). The purpose of this study was (1) to evaluate contrast savings with the AVERT and (2) to evaluate the ability to generate clinically acceptable DSA images in the process. To better define the mechanism of action in the peripheral circulation, we also developed a bench model to study the effects of the AVERT on the hydrodynamics of contrast delivery., Methods: Patients undergoing lower extremity DSA (diagnostic or intervention, sheath or catheter) were studied. The following variables were recorded for each injection: starting control syringe contrast volume, contrast volume injected towards patient, contrast volume returned to AVERT reservoir, net contrast administered to the patient and % savings. The AVERT resistance was adjusted manually based on operator's discretion--balancing image quality and contrast savings., Results: About 408 DSA angiographic sequences were obtained in 22 patients undergoing 29 procedures. Almost 68% of the patients had chronic kidney disease. An 82% presented with critical limb ischemia, 18% had claudication. There was an overall 37% ± 14% savings of contrast (31% for diagnostic DSA, 40% for interventional procedures). Overall 91% of all images were acceptable for clinical decision making. Specifically, 94% of diagnostic and 87% of interventional images were acceptable. Injection through a 4 Fr catheter (77% acceptable) resulted in poorer image quality as compared to a 5 Fr catheter (96% acceptable). Image quality for 5, 6, and 7 Fr sheath injections was 86%, 91%, 98%, respectively. The bench model of peripheral angiography demonstrated a significant reduction in reflux of contrast proximal to the end of the catheter without loss of antegrade image quality - confirming the in vivo findings., Conclusions: We demonstrate that the use of the AVERT device during peripheral angiography results in significant contrast savings without compromising image quality., (© 2015 Wiley Periodicals, Inc.)

Background & Aims: Liver ultrasound (US) is usually used in the clinical setting for the diagnosis and follow-up of patients with nonalcoholic fatty liver disease (NAFLD). However, no large study has carefully assessed its performance using a semiquantitative ultrasonographic scoring system in overweight/obese patients, in comparison to magnetic resonance spectroscopy ((1) H-MRS) and histology., Methods: We recruited 146 patients and performed: a liver US using a 5-parameter scoring system, a liver (1) H-MRS to quantify liver fat content, and a liver biopsy to assess histology. All measurements were repeated in a subgroup of patients (n = 62) after 18 months of follow-up., Results: The performance of liver US (parenchymal echo alone) was rather modest, and significantly worse than (1) H-MRS (AUROC: 0.82 [0.69-0.94] vs. 0.96 [0.90-1.00]; P = 0.04). However, the AUROC improved when different echographic parameters were taken into account (AUROC: 0.89 [0.83-0.96], P = 0.15 against (1) H-MRS). Optimum sensitivity for liver US was achieved at a liver fat content ≥12.5%, suggesting that below this threshold, liver US is less sensitive. Liver (1) H-MRS showed a high accuracy for the diagnosis of NAFLD, and correlated strongly with histological steatosis (r = 0.73, P < 0.0001). None of the imaging tests was adequate enough to predict changes over time in histology., Conclusions: Despite its widespread use, liver US has several important limitations that healthcare providers should recognize, particularly because of its low sensitivity. Using a combination of echographic parameters, liver US showed a significant improvement in its diagnostic performance, but still was of limited value for monitoring treatment over time., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Chronic total occlusions (CTOs) are reported in up to 40% of patients with symptomatic peripheral arterial disease. The Viance Crossing catheter (Covidien) and the CrossBoss catheter (Boston Scientific) are novel devices that facilitate either true lumen or subintimal navigation across CTOs. The purpose of this study was to examine the acute procedural success of these devices for popliteal and below-the-knee (BTK) CTOs., Methods: Clinical and procedural outcome data between Sept 2010 and October 2013 were analyzed from the ongoing multicenter XLPAD registry. Technical success was defined as true lumen passage of the catheter, while procedural success was defined as successful vessel revascularization inclusive of subintimal passage and reentry., Results: Twenty-nine patients underwent 31 procedures, in which 37 lesions were treated with the Viance and CrossBoss catheters. Mean age of the group was 69.1 ± 10.7 years and 26 patients were male (90%). All patients (100%) had hypertension, 62% were diabetic, and 48% were active smokers. Critical limb ischemia was the indication for the procedure in 58% of cases; mean Rutherford class was 4.2 ± 1.2 for the entire cohort. Target CTOs included 14 anterior tibial, 9 posterior tibial, 5 peroneal, 1 tibio-peroneal trunk, and 8 popliteal artery lesions. Mean lesion length was 81 ± 64 mm; 15 lesions (41%) were severely calcified. True lumen passage was obtained in 24 lesions (65% technical success). Subintimal entry was achieved in 5 lesions (14%). Procedural success was achieved in 26 lesions (70%). Procedural failure was related to longer lesion length (P<.001), and mean length of failed lesions was 136 ± 65 mm., Conclusion: Viance and CrossBoss catheters were associated with an overall 70% procedural success with predominantly true lumen crossing in a BTK-CTO cohort. CTO length remains an important determinant of device success.

Unlabelled: Hyperinsulinemia is believed to play a key role in the pathogenesis of nonalcoholic steatohepatitis (NASH) and associated cardiovascular risk. However, the relative contribution of insulin clearance to hyperinsulinemia and its relationship to liver histology have not been carefully evaluated before. To examine this, we enrolled 190 patients (32 without nonalcoholic fatty liver disease [NAFLD], 36 with simple steatosis [SS], and 122 with biopsy-proven NASH). Insulin secretion and hepatic insulin clearance were estimated by means of an oral glucose tolerance test, whereas peripheral insulin sensitivity and whole-body insulin clearance were measured during a euglycemic insulin clamp. A liver biopsy was performed to assess histology (grade/stage). Patients with NASH had similar hepatic insulin sensitivity, compared to patients with SS, but more severe adipose tissue insulin resistance and worse hyperinsulinemia. Patients with SS and NASH had a similar ∼30% reduction (P<0.01) in hepatic insulin clearance, when compared to patients without NAFLD. Reduced hepatic insulin clearance was not associated with severity of inflammation, ballooning, and fibrosis. In contrast, worse histological inflammation and ballooning (but not steatosis or fibrosis) were associated with a progressive reduction in whole-body insulin clearance (P<0.001 for trend). There was no significant difference in insulin secretion between patients with SS versus NASH., Conclusion: Decreased hepatic insulin clearance develops with a mild increase in liver fat (LFAT) accumulation. It appears to be largely driven by hepatic steatosis, whereas steatohepatitis is more closely associated with reduced whole-body insulin clearance. Hyperinsulinemia in NAFLD correlated strongly with impaired insulin clearance, but not with insulin secretion. Strategies that reduce LFAT and improve insulin clearance hold the potential to revert the unfavorable effects of hyperinsulinemia in these patients., (© 2014 by the American Association for the Study of Liver Diseases.)

Background & Aims: Liver biopsy is the only reliable way of diagnosing and staging NASH but its invasive nature limits its use. Plasma caspase-generated cytokeratin-18 fragments (CK-18) have been proposed as a non-invasive alternative. We studied its clinical value in a large multiethnic NAFLD population and examined its relationship to clinical/metabolic/histological parameters., Methods: 424 middle-aged subjects in whom we measured adipose tissue, liver and muscle insulin resistance (IR), liver fat by MRS (n=275) and histology (n=318)., Results: Median CK-18 were elevated in patients with vs. without NAFLD by MRS (209 [IQR: 137-329] vs. 122 [IQR: 98-155]U/L) or with vs. without NASH (232 [IQR: 151-387] vs. 170 [IQR: 135-234]U/L, both p<0.001). Plasma CK-18 raised significantly with any increase in steatosis, inflammation and fibrosis, but there was a significant overlap across disease severity. The CK-18 AUROC to predict NAFLD, NASH or fibrosis were 0.77 (95% CI=0.71-0.84), 0.65 (95% CI=0.59-0.71) and 0.68 (95% CI=0.61-0.75), respectively. The overall sensitivity/specificity for NAFLD, NASH and fibrosis were 63% (57-70%)/83% (69-92%), 58% (51-65%)/68% (59-76%) and 54% (44-63%)/85% (75-92%), respectively. CK-18 correlated most strongly with ALT (r=0.57, p<0.0001) and adipose tissue IR (insulin-suppression of FFA: r=-0.43; p<0.001), less with steatosis, lobular inflammation and fibrosis (r=0.28-0.34, all p<0.001), but not with ballooning, BMI, metabolic syndrome or T2DM., Conclusions: Plasma CK-18 has a high specificity for NAFLD and fibrosis, but its limited sensitivity makes it inadequate as a screening test for staging NASH. Whether combined as a diagnostic panel with other biomarkers or clinical/laboratory tests may prove useful requires further study., (Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Unlabelled: The role of adipose tissue insulin resistance in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) remains unclear. To evaluate this, we measured in 207 patients with NAFLD (age = 51 ± 1, body mass index = 34.1 ± 0.3 kg/m(2) ) and 22 controls without NAFLD (no NAFLD) adipose tissue insulin resistance by means of a validated index (Adipo-IR(i) = plasma free fatty acids [FFA] x insulin [FPI] concentration) and as the suppression of plasma FFA during an oral glucose tolerance test and by a low-dose insulin infusion. We also explored the relationship between adipose tissue insulin resistance with metabolic and histological parameters by dividing them based on quartiles of adipose tissue insulin resistance (Adipo-IR(i) quartiles: Q1 = more sensitive; Q4 = more insulin resistant). Hepatic insulin resistance, measured as an index derived from endogenous glucose production x FPI (HIRi), and muscle insulin sensitivity, were assessed during a euglycemic insulin clamp with 3-[(3) H] glucose. Liver fat was measured by magnetic resonance imaging and spectroscopy, and a liver biopsy was performed to assess liver histology. Compared to patients without steatosis, patients with NAFLD were insulin resistant at the level of adipose tissue, liver, and skeletal muscle and had higher plasma aspartate aminotransferase and alanine aminotransferase, triglycerides, and lower high-density lipoprotein cholesterol and adiponectin levels (all P < 0.01). Metabolic parameters, hepatic insulin resistance, and liver fibrosis (but not necroinflammation) deteriorated as quartiles of adipose tissue insulin resistance worsened (all P < 0.01)., Conclusion: Adipose tissue insulin resistance plays a key role in the development of metabolic and histological abnormalities of obese patients with NAFLD. Treatment strategies targeting adipose tissue insulin resistance (e.g., weight loss and thiazolidinediones) may be of value in this population., (Copyright © 2012 American Association for the Study of Liver Diseases.)

Objective: Prediabetes and type 2 diabetes mellitus (T2DM) are believed to be common and associated with a worse metabolic profile in patients with nonalcoholic fatty liver disease (NAFLD). However, no previous study has systematically screened this population., Research Design and Methods: We studied the prevalence and the metabolic impact of prediabetes and T2DM in 118 patients with NAFLD. The control group comprised 20 subjects without NAFLD matched for age, sex, and adiposity. We measured 1) plasma glucose, insulin, and free fatty acid (FFA) concentration during an oral glucose tolerance test; 2) liver fat by magnetic resonance spectroscopy (MRS); 3) liver and muscle insulin sensitivity (euglycemic insulin clamp with 3-[(3)H]glucose); and 4) indexes of insulin resistance (IR) at the level of the liver (HIR(i)= endogenous glucose production × fasting plasma insulin [FPI]) and adipose tissue (Adipo-IR(i)= fasting FFA × FPI)., Results: Prediabetes and T2DM was present in 85% versus 30% in controls (P < 0.0001), all unaware of having abnormal glucose metabolism. NAFLD patients were IR at the level of the adipose tissue, liver, and muscle (all P < 0.01-0.001). Muscle and liver insulin sensitivity were impaired in patients with NAFLD to a similar degree, whether they had prediabetes or T2DM. Only adipose tissue IR worsened in T2DM and correlated with the severity of muscle (r = 0.34; P < 0.001) and hepatic (r = 0.57; P < 0.0001) IR and steatosis by MRS (r = 0.35; P < 0.0001)., Conclusions: Patients with NAFLD may benefit from early screening for T2DM, because the prevalence of abnormal glucose metabolism is much higher than previously appreciated. Regardless of glucose tolerance status, severe IR is common. In patients with T2DM, adipose tissue IR appears to play a major role in the severity of NAFLD.

Unlabelled: The role of ethnicity in determining disease severity in nonalcoholic steatohepatitis (NASH) remains unclear. We recruited 152 patients with biopsy-proven NASH, 63% of whom were Hispanic and 37% of whom were Caucasian. Both groups were well matched for age, sex, and total body fat. We measured: (1) liver fat by magnetic resonance imaging and spectroscopy; (2) fasting plasma glucose, fasting plasma insulin (FPI), and free fatty acid (FFA) levels; (3) total body fat by dual energy x-ray absorptiometry (DXA); (4) liver and muscle insulin sensitivity (insulin clamp with 3-[(3)H] glucose); (5) insulin resistance at the level of the liver (fasting endogenous glucose production derived from 3-[(3)H] glucose infusion × FPI) and adipose tissue (fasting FFA × FPI). Liver fat was slightly, but not significantly, higher in Hispanic vs. Caucasian patients (27 ± 2% vs. 24 ± 2%, p = 0.16). However, this trend did not translate into worse liver steatosis, necroinflammation or fibrosis. Patients with NASH had severe hepatic, adipose tissue and muscle insulin resistance versus healthy subjects without NASH nonalcoholic fatty liver disease, but there were no differences between both ethnic groups on these parameters. However, Hispanics versus Caucasians with type 2 diabetes mellitus (T2DM) had a trend for worse hepatic/adipose tissue insulin resistance and fibrosis., Conclusion: When Hispanic and Caucasian patients with NASH are well matched for clinical parameters, particularly for adiposity, slightly higher liver fat content is not associated with worse hepatic insulin resistance or more severe NASH on histology. Hispanic ethnicity does not appear to be a major determinant of disease severity in NASH, although those with diabetes may be at greater risk of fibrosis. Given the higher risk of T2DM in Hispanics, long-term studies are needed to define their risk of disease progression., (Copyright © 2011 American Association for the Study of Liver Diseases.)