Circulation, viral diversity and genomic rearrangement in mpox virus in the Netherlands during the 2022 outbreak and beyond.

Mpox is an emerging zoonotic disease which has now spread to over 113 countries as of August 2023, with over 89,500 confirmed human cases. The Netherlands had one of the highest incidence rates in Europe during the peak of the outbreak. In this study, we generated 158 near-complete mpox virus (MPXV) genomes (12.4% of nationwide cases) that were collected throughout the Netherlands from the start of the outbreak in May 2022 to August 2023 to track viral evolution and investigate outbreak dynamics. We detected 14 different viral lineages, suggesting multiple introductions followed by rapid initial spread within the country. The estimated evolutionary rate was relatively high compared to previously described in orthopoxvirus literature, with an estimated 11.58 mutations per year. Genomic rearrangement events occurred at a rate of 0.63% and featured a large deletion event. In addition, based on phylogenetics, we identified multiple potential transmission clusters which could be supported by direct source- and contact tracing data. This led to the identification of at least two main transmission locations at the beginning of the outbreak. We conclude that whole genome sequencing of MPXV is essential to enhance our understanding of outbreak dynamics and evolution of a relatively understudied and emerging zoonotic pathogen.

Time Scales of Human Mpox Transmission in The Netherlands.

Mpox has spread rapidly to many countries in nonendemic regions. After reviewing detailed exposure histories of 109 pairs of mpox cases in the Netherlands, we identified 34 pairs where transmission was likely and the infectee reported a single potential infector with a mean serial interval of 10.1 days (95% credible interval, 6.6-14.7 days). Further investigation into pairs from 1 regional public health service revealed that presymptomatic transmission may have occurred in 5 of 18 pairs. These findings emphasize that precaution remains key, regardless of the presence of recognizable symptoms of mpox.

Prevalence and Predictors of Nonadherence to Direct Oral Anticoagulant Treatment in Patients with Atrial Fibrillation.

Background For most patients with newly diagnosed atrial fibrillation (AF), direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists. However, there is concern that the lack of monitoring may impair therapy adherence and therefore the anticoagulant effect. Objective To assess 1-year DOAC nonadherence in patients with AF and a treatment indication of at least 1 year in the Dutch health care setting, and to identify predictors of nonadherence. Methods We performed a near-nationwide historical cohort study in patients with a novel DOAC indication for AF. Data were obtained from a pharmacy database, covering 65% of all outpatient prescriptions dispensed in the Netherlands. The 1-year nonadherence was assessed by the proportion of days covered; the threshold was set at <80%. Robust Poisson regression analyses were performed to identify predictors of nonadherence. Results A total of 46,211 patients were included and the 1-year nonadherence was 6.5%. We identified male sex (risk ratio [RR] 1.23, 95% confidence interval [CI]: 1.15-1.33), younger age (age ≥60 to <70 years: RR: 1.15, 95% CI: 1.00-1.33, age <60 years: RR: 2.22, 95% CI: 1.92-2.57; reference age ≥85 years), a reduced DOAC dose (RR: 1.10, 95% CI: 1.00-1.22), a twice-daily dosing regimen (RR: 1.21, 95% CI: 1.12-1.30), and treatment with apixaban (RR: 1.16, 95% CI: 1.06-1.26, reference rivaroxaban) or dabigatran (RR: 1.25, 95% CI: 1.14-1.37) as independent predictors of 1-year nonadherence. Conclusion One-year nonadherence to DOACs was low yet relevant in patients with AF newly prescribed a DOAC. Understanding the predictors for nonadherence may help identify patients at risk.

Use of the National Early Warning Score for predicting deterioration of patients with acute pulmonary embolism: a post-hoc analysis of the YEARS Study.

BACKGROUND: The Pulmonary Embolism Severity Index (PESI) and the simplified PESI (sPESI) are validated scores for mortality prediction in patients with pulmonary embolism (PE). National Early Warning Score (NEWS) is a general prognostic risk score for multiple clinical settings. We investigated whether the NEWS had a comparable performance with the PESI and sPESI, for predicting intensive care unit (ICU) admission and death in patients with acute PE. METHODS: In haemodynamically stable patients with confirmed PE from the YEARS Study (2013-2015), we evaluated the performance of the NEWS, PESI and sPESI for predicting 7-day ICU admission and 30-day mortality. Receiver operating characteristic curves were plotted and the area under the curve (AUC) was calculated. RESULTS: Of 352 patients, 12 (3.4%) were admitted to the ICU and 5 (1.4%) died. The AUC of the NEWS for ICU admission was 0.80 (95% CI 0.66 to 0.94) and 0.92 (95% CI 0.82 to 1.00) for 30-day mortality. At a threshold of 3 points, NEWS yielded a sensitivity and specificity of 92% and 53% for ICU admission and 100% and 52% for 30-day mortality. The AUC of the PESI was 0.64 (95% CI 0.48 to 0.79) for ICU admission and 0.94 (95% CI 0.87 to 1.00) for mortality. At a threshold of 66 points, PESI yielded a sensitivity of 75% and a specificity of 38% for ICU admission. For mortality, these were 100% and 37%, respectively. The performance of the sPESI was similar to that of PESI. CONCLUSION: In comparison with PESI and sPESI, NEWS adequately predicted 7-day ICU admission as well as 30-day mortality, supporting its potential relevance for clinical practice.

Diagnostic efficacy of ECG-derived ventricular gradient for the detection of chronic thromboembolic pulmonary hypertension in patients with acute pulmonary embolism.

INTRODUCTION: Application of the chronic thromboembolic pulmonary hypertension (CTEPH) rule out criteria (manual electrocardiogram [ECG] reading and N-terminal pro-brain natriuretic peptide [NTproBNP] test) can rule out CTEPH in pulmonary embolism (PE) patients with persistent dyspnea (InShape II algorithm). Increased pulmonary pressure may also be identified using automated ECG-derived ventricular gradient optimized for right ventricular pressure overload (VG-RVPO). METHOD: A predefined analysis of the InShape II study was performed. The diagnostic performance of the VG-RVPO for the detection of CTEPH and the incremental diagnostic value of the VG-RVPO as new rule-out criteria in the InShape II algorithm were evaluated. RESULTS: 60 patients were included; 5 (8.3%) were ultimately diagnosed with CTEPH. The mean baseline VG-RVPO (at time of PE diagnosis) was -18.12 mV·ms for CTEPH patients and - 21.57 mV·ms for non-CTEPH patients (mean difference 3.46 mV·ms [95%CI -29.03 to 35.94]). The VG-RVPO (after 3-6 months follow-up) normalized in patients with and without CTEPH, without a clear between-group difference (mean Δ VG-RVPO of -8.68 and - 8.42 mV·ms respectively; mean difference of -0.25 mV·ms, [95%CI -12.94 to 12.44]). The overall predictive accuracy of baseline VG-RVPO, follow-up RVPO and Δ VG-RVPO for CTEPH was moderate to poor (ROC AUC 0.611, 0.514 and 0.539, respectively). Up to 76% of the required echocardiograms could have been avoided with VG-RVPO criteria replacing the InShape II rule-out criteria, however at cost of missing up to 80% of the CTEPH diagnoses. CONCLUSION: We could not demonstrate (additional) diagnostic value of VG-RVPO as standalone test or as on top of the InShape II algorithm.

Postthrombotic syndrome and quality of life after deep vein thrombosis in patients treated with edoxaban versus warfarin.

Background: Postthrombotic syndrome (PTS) is a long-term complication after deep vein thrombosis (DVT) and can affect quality of life (QoL). Pathogenesis is not fully understood but inadequate anticoagulant therapy with vitamin K antagonists is a known risk factor for the development of PTS. Objectives: To compare the prevalence of PTS after acute DVT and the long-term QoL following DVT between patients treated with edoxaban or warfarin. Methods: We performed a long-term follow-up study in a subset of patients with DVT who participated in the Hokusai-VTE trial between 2010 and 2012 (NCT00986154). Primary outcome was the prevalence of PTS, defined by the Villalta score. The secondary outcome was QoL, assessed by validated disease-specific (VEINES-QOL) and generic health-related (SF-36) questionnaires. Results: Between 2017 and 2020, 316 patients were enrolled in 26 centers in eight countries, of which 168 (53%) patients had been assigned to edoxaban and 148 (47%) to warfarin during the Hokusai-VTE trial. Clinical, demographic, and thrombus-specific characteristics were comparable for both groups. Mean (SD) time since randomization in the Hokusai-VTE trial was 7.0 (1.0) years. PTS was diagnosed in 85 (51%) patients treated with edoxaban and 62 (42%) patients treated with warfarin (adjusted odds ratio 1.6, 95% CI 1.0-2.6). Mean differences in QoL scores between treatment groups were not clinically relevant. Conclusion: Contrary to our hypothesis, the prevalence of PTS tended to be higher in patients treated with edoxaban compared with warfarin. No differences in QoL were observed. Further research is warranted to unravel the role of anticoagulant therapy on development of PTS.

Effect of polypharmacy on bleeding with rivaroxaban versus vitamin K antagonist for treatment of venous thromboembolism.

BACKGROUND: Polypharmacy, including use of inhibitors of CYP3A4 and P-glycoprotein (P-gp), is common in patients with venous thromboembolism (VTE) and is associated with increased bleeding. METHODS: In 8246 patients included in the EINSTEIN-VTE studies for acute VTE, we evaluated the effect of polypharmacy on bleeding and on the relative differences between rivaroxaban and enoxaparin/vitamin K antagonist (VKA). We assessed the incidence of clinically relevant bleeding (major and clinically relevant nonmajor bleeding) by number of comedications (none, 1-3, ≥4) at baseline, and by use of CYP3A4 and/or P-gp inhibitors. Interaction between rivaroxaban versus enoxaparin/VKA and comedication was assessed by Cox regression analysis with pinteraction estimates. RESULTS: With increasing number of comedications, the incidence of clinically relevant bleeding rose from 5.7% to 13.3% in rivaroxaban recipients and from 9.1% to 11.1% in enoxaparin/VKA recipients. Whereas rivaroxaban was associated with a reduced bleeding risk compared with enoxaparin/VKA in patients without comedication (hazard ratio [HR] 0.6, 95% confidence interval [CI] 0.4-0.9), the risk was similar in patients with ≥4 comedications (HR 1.2, 95% CI 0.97-1.5, pinteraction .002). Use of CYP3A4 and/or P-gp inhibitors was associated with a doubled bleeding risk compared with no use, without a difference between rivaroxaban and enoxaparin/VKA. CONCLUSION: We conclude that fixed-dose rivaroxaban as compared with enoxaparin followed by dose-adjusted VKA is not associated with an increased bleeding risk in patients with VTE administered polypharmacy in general and CYP3A4 and/or P-gp inhibitors specifically. This implies that the observed increased bleeding risks with polypharmacy and use of CYP3A4 and/or P-gp inhibitors are likely explained by comorbidities and frailty, and not by pharmacokinetic interactions.

Epidemiologic and Genomic Analysis of SARS-CoV-2 Delta Variant Superspreading Event in Nightclub, the Netherlands, June 2021.

We report a severe acute respiratory syndrome coronavirus 2 superspreading event in the Netherlands after distancing rules were lifted in nightclubs, despite requiring a negative test or vaccination. This occurrence illustrates the potential for rapid dissemination of variants in largely unvaccinated populations under such conditions. We detected subsequent community transmission of this strain.

Quality of life in patients with pulmonary embolism treated with edoxaban versus warfarin.

BACKGROUND: Long-term sequelae of acute pulmonary embolism (PE) include decreased quality of life (QoL). Evidence suggests that adequacy of initial anticoagulant treatment in the acute phase of venous thrombosis has a key impact on late postthrombotic complications. We hypothesize that patients with acute PE treated with edoxaban for acute PE experience have improved QoL compared to those treated with warfarin. METHODS: Patients with PE who participated in the Hokusai-VTE trial were contacted between June 2017 and September 2020 for a single long-term follow-up visit. Main outcomes were the generic and disease-specific QoL measured by the 36-Item Short Form Health Survey (SF-36) and Pulmonary Embolism Quality of Life questionnaire. RESULTS: We included 251 patients from 26 centers in eight countries, of which 129 (51%) had been assigned to edoxaban and 122 (49%) to warfarin. Patient- and thrombus-specific characteristics were similar in both groups. Mean time since randomization in the Hokusai-VTE trial was 7.0 years (standard deviation, 1.0). No relevant or statistical differences were observed in the QoL for patients treated with edoxaban compared to patients treated with warfarin. The mean difference between patients treated with edoxaban and patients with PE treated with warfarin was 0.8 (95% confidence interval [CI]. -1.6 to 3.2) for the SF-36 summary mental score and 1.6 (95% CI, -0.9 to 4.1) for summary physical score. CONCLUSION: Our findings indicate that patients with an index PE treated with edoxaban or warfarin have a similar long-term QoL. Since our study was a follow-up study from a well-controlled clinical trial setting, future studies should be designed in a daily clinical practice setting. We suggest a longitudinal design for investigation of changes in QoL over time.

Recurrent bleeding and thrombotic events after resumption of oral anticoagulants following gastrointestinal bleeding: Communication from the ISTH SSC Subcommittee on Control of Anticoagulation.

BACKGROUND: Gastrointestinal bleeding frequently complicates anticoagulant therapy causing treatment discontinuation. Data to guide the decision regarding whether and when to resume anticoagulation based on the risks of thromboembolism and recurrent bleeding are scarce. OBJECTIVES: We aimed to retrospectively evaluate the incidence of these events after anticoagulant-related gastrointestinal bleeding and assess their relationship with timing of anticoagulation resumption. METHODS: Patients hospitalized because of gastrointestinal bleeding during oral anticoagulation for any indication were eligible. All patients were followed up to 2 years after the index bleeding for recurrent major or clinically relevant non-major bleeding, venous or arterial thromboembolism, and mortality. RESULTS: We included 948 patients hospitalized for gastrointestinal bleeding occurring during treatment with vitamin K antagonists (n = 531) or direct oral anticoagulants (n = 417). In time-dependent analysis, anticoagulant treatment was associated with a higher risk of recurrent clinically relevant bleeding (hazard ratio [HR] 1.55; 95% confidence interval [CI] 1.08-2.22), but lower risk of thromboembolism (HR 0.34; 95% CI 0.21-0.55), and death (HR 0.50; 95% CI 0.36-0.68). Previous bleeding, index major bleeding, and lower glomerular filtration rate were associated with a higher risk of recurrent bleeding. The incidence of recurrent bleeding increased after anticoagulation restart independently of timing of resumption. CONCLUSIONS: Anticoagulant treatment after gastrointestinal bleeding is associated with a lower risk of thromboembolism and death, but higher risk of recurrent bleeding. The latter seemed to be influenced by patient characteristics and less impacted by time of anticoagulation resumption.

Non-invasive early exclusion of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: the InShape II study.

BACKGROUND: The current diagnostic delay of chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary embolism (PE) is unacceptably long, causing loss of quality-adjusted life years and excess mortality. Validated screening strategies for early CTEPH diagnosis are lacking. Echocardiographic screening among all PE survivors is associated with overdiagnosis and cost-ineffectiveness. We aimed to validate a simple screening strategy for excluding CTEPH early after acute PE, limiting the number of performed echocardiograms. METHODS: In this prospective, international, multicentre management study, consecutive patients were managed according to a screening algorithm starting 3 months after acute PE to determine whether echocardiographic evaluation of pulmonary hypertension (PH) was indicated. If the 'CTEPH prediction score' indicated high pretest probability or matching symptoms were present, the 'CTEPH rule-out criteria' were applied, consisting of ECG reading and N-terminalpro-brain natriuretic peptide. Only if these results could not rule out possible PH, the patients were referred for echocardiography. RESULTS: 424 patients were included. Based on the algorithm, CTEPH was considered absent in 343 (81%) patients, leaving 81 patients (19%) referred for echocardiography. During 2-year follow-up, one patient in whom echocardiography was deemed unnecessary by the algorithm was diagnosed with CTEPH, reflecting an algorithm failure rate of 0.29% (95% CI 0% to 1.6%). Overall CTEPH incidence was 3.1% (13/424), of whom 10 patients were diagnosed within 4 months after the PE presentation. CONCLUSIONS: The InShape II algorithm accurately excluded CTEPH, without the need for echocardiography in the overall majority of patients. CTEPH was identified early after acute PE, resulting in a substantially shorter diagnostic delay than in current practice.

Diagnostic accuracy of four different D-dimer assays: A post-hoc analysis of the YEARS study.

INTRODUCTION: For exclusion of pulmonary embolism (PE) clinical decision rules in combination with a D-dimer assay are applied. Currently available D-dimer assays are not standardized and it is unknown whether these differences have an impact on diagnostic management of suspected PE. Therefore, the aim is to explore differences between D-dimer assays and their impact on diagnostic outcome. METHODS: Data from all patients included in the YEARS study were collected. The YEARS study is a prospective, multicentre, cohort outcome study evaluating 3462 patients with suspected PE in which four different D-dimer assays were applied (Liatest, Innovance, Tinaquant, Vidas). Median D-dimer concentrations were calculated for each D-dimer assay. Sensitivity, specificity, PPV and NPV for detection of PE of all four assays were determined in patients without YEARS items and in those with ≥1 YEARS items (i.e. symptomatic deep vein thrombosis, haemoptysis, and whether PE is the most likely diagnosis). RESULTS: A total of 1323, 1100, 768 and 271 D-dimer concentrations were collected using the Liatest Innovance, Tinaquant and Vidas assay, respectively. Median D-dimer concentrations differed significantly between assays, with lowest values in the Tinaquant assay. In patients without YEARS items using a cutoff level of 1000 ng/mL, the NPV varied from 99,5 to 100%. In patients with ≥1 YEARS items using a 500 ng/mL cutoff, the NPV varied from 97,0 to 100% depending on the assay. CONCLUSIONS: The overall high NPV for all assays demonstrates the clinical value of the D-dimer assay. However, these results confirm differences between D-dimer assays, which have an impact on follow-up imaging. This emphasizes the need for standardization of D-dimer assays.

Outcome of intracranial bleeding managed with prothrombin complex concentrate in patients on direct factor Xa inhibitors or vitamin K antagonists.

Intracranial hemorrhage (ICH) is the most feared complication of anticoagulation with a high mortality and morbidity. Before registration of a specific reversal agent for factor Xa inhibitors (FXa-I), international guidelines recommended prothrombin complex concentrate (PCC), which also is the specific reversal agent for vitamin K antagonists (VKA). In two contemporary cohorts, we compared clinical outcomes between patients with FXa-I and VKA related ICH treated with PCC between 2014 and 2018. Primary outcome was effective hemostasis after 24 h, according to the International Society of Thrombosis and Hemostasis definition. Safety outcomes were defined as venous and arterial thromboembolic complications and death within 30 days. Thirty-six patients with FXa-I-ICH and 39 patients with VKA-ICH were available for analysis. Baseline characteristics were comparable between both groups, except for time from start of symptoms to presentation at the hospital. In the FXa-I-ICH cohort, 24 (73%) patients achieved effective hemostasis compared to 23 (62%) patients in the VKA-ICH cohort (crude odds ratio [OR] 1.62 [95%CI 0.59-4.48], adjusted OR 1.45 [95%CI 0.44-4.83]). Eight (24%) patients with FXa-I-ICH deceased compared to 17 (45%) patients with VKA-ICH (crude OR 0.38 [95%CI 0.14-1.24], adjusted OR 0.41 [95%CI 0.12-1.24]). In this observational cohort study, the outcome of ICH managed with PCC was similar in patients with FXa-I-ICH and in patients with VKA-ICH.

Treatment of Venous Thromboembolism in Special Populations with Direct Oral Anticoagulants.

As a result of the successful completion of their respective phase III studies compared with vitamin K antagonists (VKAs), four direct oral anticoagulants (DOACs) have been approved for the treatment and secondary prevention of venous thromboembolism (VTE). These DOACs-apixaban, dabigatran, edoxaban, and rivaroxaban-have subsequently seen a steady uptake among clinicians since their approval. Despite the suitability of DOACs for a broad range of patients, they are not appropriate in certain situations, whereas in others they require additional considerations such as dose reductions. Subanalyses of phase III trials and studies on specific VTE patient populations have been conducted to evaluate the safety and efficacy of the DOACs in a broad range of settings, such as patients with renal impairment, patients with cancer, patients of childbearing potential, patients with multiple comorbidities and pediatric patients. Furthermore, many recent guidance documents from important hematological societies and other specialists have incorporated several of these developments. These documents also identify the patients for whom DOACs are not suitable and where traditional anticoagulation options such as heparins or VKAs should be considered instead. This review provides an overview of key VTE patient subgroups, the clinical evidence supporting the use of anticoagulation in these patients, and a discussion of the most appropriate approaches to their management, including considerations such as dosing, acute and extended treatment durations, and DOAC selection.

Current practice patterns of outpatient management of acute pulmonary embolism: A post-hoc analysis of the YEARS study.

BACKGROUND: Studies have shown the safety of home treatment of patients with pulmonary embolism (PE) at low risk of adverse events. Management studies focusing on home treatment have suggested that 30% to 55% of acute PE patients could be treated at home, based on the HESTIA criteria, but data from day-to-day clinical practice are largely unavailable. AIM: To determine current practice patterns of home treatment of acute PE in the Netherlands. METHOD: We performed a post-hoc analysis of the YEARS study. The main outcomes were the proportion of patients who were discharged <24 h and reasons for admission if treated in hospital. Further, we compared the 3-month incidence of PE-related unscheduled readmissions between patients treated at home and in hospital. RESULTS: Of the 404 outpatients with PE included in this post-hoc analysis of the YEARS study, 184 (46%) were treated at home. The median duration of admission of the hospitalized patients was 3.0 days. The rate of PE-related readmissions of patients treated at home was 9.7% versus 8.6% for hospitalized patients (crude hazard ratio 1.1 (95% CI 0.57-2.1)). The 3-month incidence of any adverse event was 3.8% in those treated at home (2 recurrent VTE, 3 major bleedings and two deaths) compared to 10% in the hospitalized patients (3 recurrent VTE, 6 major bleedings and fourteen deaths). CONCLUSIONS: In the YEARS study, 46% of patients with PE were treated at home with low incidence of adverse events. PE-related readmission rates were not different between patients treated at home or in hospital.

Emergencies on direct oral anticoagulants: Management, outcomes, and laboratory effects of prothrombin complex concentrate.

BACKGROUND: In the initial absence of specific reversal agents for factor Xa inhibitors (FXa-Is), prothrombin complex concentrate (PCC) as a hemostatic agent has been recommended by guidelines. Since 2017, idarucizumab has been registered for dabigatran reversal. Still, data on the clinical outcome of direct oral anticoagulant (DOAC)-related emergencies (major bleeding or urgent interventions) is scarce. In addition, it is unknown to what extent PCC restores thrombin generation in FXa-I-related emergencies. Our aim was to describe management and clinical outcomes of DOAC-related emergencies and to assess the laboratory effect of PCC in patients with FXa-I emergencies. METHODS: In this prospective cohort study in 5 Dutch hospitals, patients presenting with DOAC-related emergencies were eligible. The primary outcome was effective hemostasis according to the ISTH definition. Safety outcomes were 30-day mortality and thromboembolic rate. In patients treated with PCC, additional blood samples were taken to assess the effect on thrombin generation. RESULTS: We included 101 patients with major bleeding (FXa-I, 76; dabigatran, 25) and 21 patients requiring an urgent intervention (FXa-I, 16; dabigatran, 5). Of patients with major bleeding, 67% were treated with PCC or idarucizumab. Effective hemostasis, 30-day mortality, and thromboembolism rate were 67%, 22%, and 1%, respectively. In a subset of bleeding patients on FXa-I managed with PCC, thrombin generation increased, with 96% immediately after PCC administration. In patients requiring an urgent intervention, effective hemostasis, 30-day mortality, and thromboembolic rate were 95%, 14%, and 5%. CONCLUSIONS: Effective hemostasis was achieved in the majority of patients presenting with DOAC-related emergencies;, thromboembolic complications were rare, and mortality was quite high.

Noninvasive Tests Do Not Accurately Differentiate Nonalcoholic Steatohepatitis From Simple Steatosis: A Systematic Review and Meta-analysis.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease is a rapidly increasing health problem. Liver biopsy analysis is the most sensitive test to differentiate between nonalcoholic steatohepatitis (NASH) and simple steatosis (SS), but noninvasive methods are needed. We performed a systematic review and meta-analysis of noninvasive tests for differentiating NASH from SS, focusing on blood markers. METHODS: We performed a systematic search of the PubMed, Medline and Embase (1990-2016) databases using defined keywords, limited to full-text papers in English and human adults, and identified 2608 articles. Two independent reviewers screened the articles and identified 122 eligible articles that used liver biopsy as reference standard. If at least 2 studies were available, pooled sensitivity (sensp) and specificity (specp) values were determined using the Meta-Analysis Package for R (metafor). RESULTS: In the 122 studies analyzed, 219 different blood markers (107 single markers and 112 scoring systems) were identified to differentiate NASH from simple steatosis, and 22 other diagnostic tests were studied. Markers identified related to several pathophysiological mechanisms. The markers analyzed in the largest proportions of studies were alanine aminotransferase (sensp, 63.5% and specp, 74.4%) within routine biochemical tests, adiponectin (sensp, 72.0% and specp, 75.7%) within inflammatory markers, CK18-M30 (sensp, 68.4% and specp, 74.2%) within markers of cell death or proliferation and homeostatic model assessment of insulin resistance (sensp, 69.0% and specp, 72.7%) within the metabolic markers. Two scoring systems could also be pooled: the NASH test (differentiated NASH from borderline NASH plus simple steatosis with 22.9% sensp and 95.3% specp) and the GlycoNASH test (67.1% sensp and 63.8% specp). CONCLUSION: In the meta-analysis, we found no test to differentiate NASH from SS with a high level of pooled sensitivity and specificity (≥80%). However, some blood markers, when included in scoring systems in single studies, identified patients with NASH with ≥80% sensitivity and specificity. Replication studies and more standardized study designs are urgently needed. At present, no marker or scoring system can be recommended for use in clinical practice to differentiate NASH from simple steatosis.