Liver-related aspects of valoctocogene roxaparvovec gene therapy for hemophilia A: expert guidance for clinical practice.

Adeno-associated virus (AAV)-based gene therapy (valoctocogene roxaparvovec) is an attractive treatment for hemophilia A. Careful clinical management is required to minimize the risk of hepatotoxicity, including assessment of baseline liver condition to determine treatment eligibility and monitoring liver function after gene therapy. This article describes recommendations (developed by a group of hemophilia experts) on hepatic function monitoring before and after gene therapy. To prevent harmful liver-related effects, gene therapy is contraindicated in patients with uncontrolled liver infections, autoimmune hepatitis, liver stiffness ≥8 kPa or cirrhosis. Before using gene therapy in patients with liver steatosis or other liver disorders, the risk of liver damage should be considered using a highly individualized approach. Treatment is not recommended in patients with abnormal liver enzymes, including alanine aminotransferase (ALT) at any level above the upper limit of normal (ULN). Therefore, pre-treatment assessment of liver health should include laboratory tests, abdominal ultrasound and liver stiffness measurements by transient elastography (TE). In the first year after therapy, ALT levels should be monitored 1-2 times/week to detect elevations ≥1.5 × ULN, which may require immunosuppressant therapy. Patients with ALT elevation should receive prednisone 60 mg/day for 2 weeks, followed by stepwise tapering when ALT returns to baseline. ALT monitoring should continue long-term (every 3-6 months), along with abdominal ultrasound (every 6 months) and TE (yearly) evaluations. When patients with good liver health are selected for treatment and closely monitored thereafter, ALT elevations can be promptly treated and are expected to resolve without long-term hepatic sequelae.

The management of liver disease in people with congenital bleeding disorders: guidance from EAHAD, EHC, ISTH, WFH.

People with bleeding disorders (PWBD) have been exposed to the risk of developing chronic viral hepatitis and cirrhosis after replacement therapy. At today, the advent of new pharmacological strategies for the control of hemostasis and the efficacious antiviral therapies against HCV and HBV have significantly reduced this risk. However, the real success for liver health in this clinical setting is based on other risk factors, among them, the severity of liver disease at time of HBV/HCV antiviral therapy and the exposure to highly prevalent factors of chronic liver damage (e.g.; metabolic dysfunction and/or alcohol) that can cause a residual risk of complications such as hepatocellular carcinoma, portal hypertension, liver insufficiency. With this background, a group of experts selected among hepatologists, PWBD treaters and patient representatives, produced this practical multisociety guidance for the protection of liver health and the prevention and management of liver complications in PWBD based on the most updated protocols of care.

Gene therapy for people with hemophilia B: a proposed care delivery model in Italy.

BACKGROUND: Gene therapy is designed to provide people with hemophilia B with a steady and elevated factor (F)IX activity, thereby strengthening protection and relieving the burden of frequent replacement therapy infusions. The European Medicines Agency has approved gene therapy for the severe and moderately severe forms of hemophilia B that uses the FIX-Padua variant (etranacogene dezaparvovec). OBJECTIVES: The aim was to provide a document dedicated to hemophilia B gene therapy and give a comprehensive overview of the topic. METHODS: An Italian group of experts in hemophilia carried out a narrative review of the literature and discussed during a virtual meeting several key aspects of the delivery of this treatment in Italy. The discussion covered the organizational model, the role of the multidisciplinary team, the laboratory surveillance, and the patient's journey, from the follow-up to the identification of safety issues and outcome measures. RESULTS: This article highlights the need to follow the Hub and Spoke organizational model and sheds light on the role of each professional figure within the multidisciplinary teams to favor patient engagement, management, and retention. Moreover, this article stresses the need to perform laboratory tests for patient screening and follow-up and proposes a checklist to help patient identification. Finally, the needs of Italian hemophilia centers have been considered to ensure an efficient implementation of the care delivery model. CONCLUSION: It is crucial to ensure that centers are appropriately organized, equipped, and trained to adequately select patients, deliver the gene therapy, and perform follow-up.

Impact of clonal hematopoiesis of indeterminate potential on hepatocellular carcinoma in individuals with steatotic liver disease.

BACKGROUND AND AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global epidemic and is the most rapidly rising cause of HCC. Clonal hematopoiesis of indeterminate potential (CHIP) contributes to neoplastic and cardiometabolic disorders and is considered a harbinger of tissue inflammation. CHIP was recently associated with increased risk of liver disease. The aim of this study was to examine whether CHIP is associated with HCC development in patients with SLD. APPROACH AND RESULTS: We considered individuals with MASLD-HCC (n=208) and controls with (n =414) and without (n =259) advanced fibrosis who underwent whole exome sequencing. CHIP was diagnosed when ≥2 variant callers identified a known myeloid mutation with variant allele frequency ≥2%. CHIP was observed in 116 participants (13.1%), most frequently in DNMT3A, TET2, TP53 , and ASXL1 , and correlated with age ( p <0.0001) and advanced liver fibrosis (p=0.001). Higher aspartate aminotransferase levels predicted non- DNMT3A -CHIP, in particular with variant allele frequency ≥10% (OR: 1.14, 1.03 -1.28 and OR: 1.30, 1.12 -1.49, respectively, p <0.05). After adjustment for sex, diabetes, and a polygenic risk, a score of inherited MASLD predisposition CHIP was associated with cirrhosis (2.00, 1.30 -3.15, p =0.02), and with HCC even after further adjustment for cirrhosis (OR: 1.81, 1.11 -2.00, 1.30 -3.15, p =0.002). Despite the strong collinearity among aging and development of CHIP and HCC, non- DNTM3A -CHIP, and TET2 lesions remained associated with HCC after full correction for clinical/genetics covariates and age (OR: 2.45, 1.35 -4.53; OR: 4.8, 1.60 -17.0, p =0.02). CONCLUSIONS: We observed an independent association between CHIP, particularly related to non- DNTM3A and TET2 genetic lesions and MASLD-HCC.

Portal hypertension-like pattern in coronavirus disease 2019 acute respiratory distress syndrome.

OBJECTIVES: Although respiratory failure is the most common feature in coronavirus disease 2019 (COVID-19), abdominal organ involvement is likewise frequently observed. To investigate visceral and thoracic circulation and abdominal organ damage in COVID-19 patients. MATERIALS AND METHODS: A monocentric observational study was carried on. In COVID-19 patients affected by acute respiratory distress syndrome (ARDS) (n = 31) or mild pneumonia (n = 60) thoracoabdominal circulation was evaluated using Doppler-ultrasound and computed tomography. The study also included non-COVID-19 patients affected by ARDS (n = 10) or portal hypertension (n = 10) for comparison of the main circulatory changes. RESULTS: Patients affected by COVID-19 ARDS showed hyperdynamic visceral flow and increased portal velocity, hepatic artery resistance-index, and spleen diameter relative to those with mild-pneumonia (p = 0.001). Splanchnic circulatory parameters significantly correlated with the main respiratory indexes (p < 0.001) and pulmonary artery diameter (p = 0.02). The chest and abdominal vascular remodeling pattern of COVID-19 ARDS patients resembled the picture observed in the PH group, while differed from that of the non-COVID ARDS group. A more severe COVID-19 presentation was associated with worse liver dysfunction and enhanced inflammatory activation; these parameters both correlated with abdominal (p = 0.04) and chest imaging measures (p = 0.03). CONCLUSION: In COVID-19 ARDS patients there are abdominal and lung vascular modifications that depict a portal hypertension-like pattern. The correlation between visceral vascular remodeling, pulmonary artery enlargement, and organ damage in these critically ill patients is consistent with a portal hyperlfow-like syndrome that could contribute to the peculiar characteristics of respiratory failure in these patients. CLINICAL RELEVANCE STATEMENT: our data suggest that the severity of COVID-19 lung involvement is directly related to the development of a portal hyperflow-like syndrome. These observations should help in defining the need for a closer monitoring, but also to develop dedicated therapeutic strategies.

Comprehensive investigation of platelet function in patients with cirrhosis.

Cirrhosis presents with thrombocytopenia and possibly thrombocytopathy. Previous studies exploring platelet function gave conflicting results and most controversies are explained by the variety of methods employed for investigation. We sought to assess in-vitro the overall platelet function in cirrhosis. We investigated 34 patients by using the following tests. (i)Aggregometry. (ii)Measurement of the content of platelet granules. (iii)Cytometric platelet activation. (iv)Plasmatic markers of in-vivo platelet activation. (v)Platelet procoagulant activity by thrombin generation (TG) in platelet-rich plasma (PRP). TG measured in PRP for patients and controls was similar. Platelets from patients with cirrhosis showed reduction of aggregation and secretion of ATP. Similar results were observed for platelet activation parameters such as P-selectin expression and PAC-1 platelet binding. Plasma levels of ßeta-thromboglobulin and soluble P-selectin, were increased in patients-vs-controls. In contrast, there were no patients-vs-controls differences for plasmatic platelet-factor-4. Results are consistent with a state of in-vivo platelet activation and decreased in-vitro aggregation. Since bleeding events following invasive procedures are uncommon in cirrhosis, we speculate that in-vitro aggregometry testing does not reflect the situation occurring in-vivo. Results of the study and pathophysiological considerations support the conclusion that platelet function in cirrhosis as determined by aggregometry, although somewhat impaired, may support the overall hemostatic potential, which is needed for most invasive interventions. These conclusions are in line with the recommendations of international guidelines, warning against indiscriminate use of prophylactic preprocedural administration of platelets before invasive procedures. Decision on platelet support should not be made based on in-vitro laboratory testing for platelet function.

Evolution of spontaneous portosystemic shunts over time and following aetiological intervention in patients with cirrhosis.

Background & Aims: Spontaneous portosystemic shunts (SPSS) develop frequently in cirrhosis. Changes over time and the effect of aetiological interventions on SPSS are unknown, so we aimed to explore the effect of these variables on SPSS evolution. Methods: Patients with cirrhosis from the Baveno VI-SPSS cohort were selected provided a follow-up abdominal CT or MRI scan was available. Clinical and laboratory data were collected at baseline and follow-up. Imaging tests were reviewed to evaluate changes in the presence and size of SPSS (large (L)-SPSS was ≥8 mm) over time. Regarding alcohol- or HCV-related cirrhosis, two populations were defined: cured patients (abstinent from alcohol or successful HCV therapy), and non-cured patients. Results: A total of 617 patients were included. At baseline SPSS distribution was 22% L-SPSS, 30% small (S)-SPSS, and 48% without (W)-SPSS. During follow-up (median follow-up of 63 months), SPSS distribution worsened: L-SPSS 26%, S-SPSS 32%, and W-SPSS 42% (p <0.001). Patients with worse liver function during follow-up showed a simultaneous aggravation in SPSS distribution. Non-cured patients (n = 191) experienced a significant worsening in liver function, more episodes of liver decompensation and lower transplant-free survival compared to cured patients (n = 191). However, no differences were observed regarding SPSS distribution at inclusion and at follow-up, with both groups showing a trend to worsening. Total shunt diameter increased more in non-cured (52%) than in cured patients (28%). However, total shunt area (TSA) significantly increased only in non-cured patients (74 to 122 mm2, p <0.001). Conclusions: The presence of SPSS in cirrhosis increases over time and parallels liver function deterioration. Aetiological intervention in these patients reduces liver-related complications, but SPSS persist although progression is decreased. Impact and implications: There is no information regarding the evolution of spontaneous portosystemic shunts (SPSS) during the course of cirrhosis, and especially after disease regression with aetiological interventions, such as HCV treatment with direct-acting antivirals or alcohol abstinence. These results are relevant for clinicians dealing with patients with cirrhosis and portal hypertension because they have important implications for the management of cirrhosis with SPSS after disease regression. From a practical point of view, physicians should be aware that in advanced cirrhosis with portal hypertension, after aetiological intervention, SPSS mostly persist despite liver function improvement, and complications related to SPSS may still develop.

Reappraisal of the conventional hemostasis tests as predictors of perioperative bleeding in the era of rebalanced hemostasis in cirrhosis.

New global laboratory procedures mimicking the in vivo hemostasis process led to the changing paradigm of cirrhosis from the prototype of hemorrhagic diseases to a condition in which hemostasis is normal but fragile, thus justifying the hemorrhagic/thrombotic tendencies that affect these patients. The new paradigm was instrumental to change the management of cirrhosis. For example, international guidelines warn against the entrenched practice of testing patients with conventional hemostasis tests and infusing those with abnormalities with fresh-frozen plasma, coagulation factor concentrates, or platelets, prior to surgery/invasive procedures. These recommendations are, however, largely disattended. The practice of testing patients with the prothrombin time or viscoelastometry and using arbitrary cutoffs to make decisions on perioperative prophylaxis is still common and probably driven by medicolegal issues. There is no doubt that prothrombin time and congeners tests are unable to predict bleeding in cirrhosis. However, it cannot be excluded that some tests may be useful in patients who are severely decompensated. Large prospective collaborative studies are warranted. Enrolled patients should be randomized to receive perioperative prophylaxis based on laboratory testing (eg, viscoelastometry, thrombomodulin-modified thrombin generation) or to usual care. However, for these trials to be useful, a third group of patients who do not receive prophylaxis should be included. In conclusion, until results from these studies are available, physicians attending cirrhosis should refrain from using laboratory tests with arbitrary cutoffs to make decision on perioperative prophylaxis. Decision should be made by considering the clinical history of individual patients and the risk of hemorrhage of specific procedures.

Splanchnic vein thrombosis associated with SARS-CoV-2 infection: A VALDIG case-control study.

Background & Aims: Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a risk factor for splanchnic vein thrombosis (SVT) is unknown. This study aims to assess the impact of SARS-CoV-2 infection on the presentation and prognosis of recent SVT and to identify specific characteristics of SARS-CoV-2-associated SVT. Methods: This is a retrospective study collecting health-related data of 27 patients presenting with recent SVT in the context of SARS-CoV-2 infection in 12 Vascular Liver Disease Group (VALDIG) centres and in comparison with 494 patients with recent SVT before the SARS-CoV-2 pandemic. Results: Twenty-one patients with SARS-CoV-2 had portal vein thrombosis with or without thrombosis of another splanchnic vein, two had superior mesenteric vein thrombosis, one had splenic vein thrombosis, and three had hepatic vein thrombosis. Diagnosis of SVT was made 10 days (95% CI 0-24 days) after the diagnosis of SARS-CoV-2 infection. Fever (52 vs. 15%; p <0.001) and respiratory symptoms (44 vs. 0%; p <0.001) were more frequent, and median lymphocyte count was lower (1.1 × 103/mm3vs. 1.6 × 103/mm3; p = 0.043) in patients with infection than in those without SARS-CoV-2 infection. A prothrombotic condition was identified in 44 and 52% of patients with and without SARS-CoV-2 infection, respectively (p = 0.5). All patients with SARS-CoV-2 received anticoagulation therapy. During a median follow-up of 250 days, three SARS-CoV-2-infected patients (11%) required intestinal resection for infarction 1 to 3 months after diagnosis of SVT compared with 13 (2.6%) controls (p = 0.044). Partial or complete recanalisation of the thrombosed splanchnic vein was performed in 33% of patients with SARS-CoV-2. Conclusions: SARS-CoV-2 infection can be associated with recent SVT. Intestinal infarction leading to intestinal resection might be more frequent in patients with SARS-CoV-2. Impact and implications: SARS-CoV-2 infection can be associated with recent SVT. SVT occurring during SARS-CoV-2 infection is characterised by a higher frequency of respiratory symptoms and a lower lymphocyte count. Intestinal infarction leading to intestinal resection appears to occur more frequently in patients with SARS-CoV-2.

Residual burden of liver disease after HCV clearance in hemophilia: a word of caution in the era of gene therapy.

Ruling out advanced fibrosis/cirrhosis is mandatory for persons with hemophilia (PWH) who are candidates for gene therapy. However, clinical evaluation and noninvasive tests (NITs) may be inaccurate after hepatitis C virus (HCV) clearance. We conducted a prospective hepatological screening to detect advanced fibrosis/cirrhosis in PWH after HCV clearance. Any risk factor of chronic liver damage was registered by using biochemical data, liver stiffness measurement (LSM), and ultrasound (US). A pre/post-HCV clearance analysis was conducted prospectively in a subgroup of patients who underwent LSM, US, and NITs for fibrosis. We evaluated 119 patients (median age, 53 years; range, 36-87 years) with a previous HCV infection (hemophilia A, n = 108; hemophilia B, n = 11). Ninety-six (81%) presented at least 1 potential risk factor of chronic liver damage. Metabolic risk factors were the most prevalent, with 51 patients (44%) having US steatosis. In 21 patients (18%), clinical, biochemical, liver morphology, and/or LSM were suggestive of advanced fibrosis/cirrhosis. Furthermore, 10 patients (8%) had esophageal varices and 3 (3%) had hepatocellular carcinoma. In 57 patients included in the prospective analysis, LSM and NITs were reduced after HCV clearance (P < .05), but US signs specific of cirrhosis remained unchanged. Overall, 23 of 80 patients (29%) with LSM <10 KPa had at least 1 US sign suggestive of advanced fibrosis/cirrhosis. A similar proportion (18%) was observed for LSM <8 KPa. Overall, risk factors of chronic liver damage are frequent after HCV clearance, but changes in LSM and NITs after clearance may be inaccurate to rule out advanced fibrosis/cirrhosis. A specific diagnostic workup is warranted to evaluate liver health in PWH in the era of gene therapy.

Carvedilol as the new non-selective beta-blocker of choice in patients with cirrhosis and portal hypertension.

Portal hypertension (PH) is the most common complication ofcirrhosis and represents the main driver of hepatic decompensation. The overarching goal of PH treatments in patients with compensated cirrhosis is to reduce the risk of hepatic decompensation (i.e development of ascites, variceal bleeding and/or hepatic encephalopathy). In decompensated patients, PH-directed therapies aim at avoiding further decompensation (i.e. recurrent/refractory ascites, variceal rebleeding, recurrent encephalopathy, spontaneous bacterial peritonitis or hepatorenal syndrome) and at improving survival. Carvedilol is a non-selective beta-blocker (NSBB) acting on hyperdynamic circulation/splanchnic vasodilation and on intrahepatic resistance. It has shown superior efficacy than traditional NSBBs in lowering PH in patients with cirrhosis and may be, therefore, the NSBB of choice for the treatment of clinically significant portal hypertension. In primary prophylaxis of variceal bleeding, carvedilol has been demonstrated to be more effective than endoscopic variceal ligation (EVL). In patients with compensated cirrhosis carvedilol achieves higher rate of hemodynamic response than propranolol, resulting in a decreased risk of hepatic decompensation. In secondary prophylaxis, the combination of EVL with carvedilol may prevent rebleeding and non-bleeding further decompensation better than that with propranolol. In patients with ascites and gastroesophageal varices, carvedilol is safe and may improve survival, as long as no impairment of the systemic hemodynamic or renal dysfunction occurs, with maintained arterial blood pressure as suitable safety surrogate. The target dose of carvedilol to treat PH should be 12.5 mg/day. This review summarizes the evidence behind Baveno-VII recommendations on the use of carvedilol in patients with cirrhosis.

Improving Management of Portal Hypertension: The Potential Benefit of Non-Etiological Therapies in Cirrhosis.

Portal hypertension is the consequence of cirrhosis and results from increased sinusoidal vascular resistance and hepatic blood inflow. Etiological therapies represent the first intervention to prevent a significant increase in portal pressure due to chronic liver damage. However, other superimposed pathophysiological drivers may worsen liver disease, including inflammation, bacterial translocation, endothelial dysfunction, and hyperactivation of hemostasis. These mechanisms can be targeted by a specific class of drugs already used in clinical practice. Albumin, rifaximin, statins, aspirin, and anticoagulants have been tested in cirrhosis and were a topic of discussion in the last Baveno consensus as non-etiological therapies. Based on the pathogenesis of portal hypertension in cirrhosis, our review summarizes the main mechanisms targeted by these drugs as well as the clinical evidence that considers them a valid complementary option to manage patients with cirrhosis and portal hypertension.

Rational hemostatic management in cirrhosis: from old paradigms to new clinical challenges.

INTRODUCTION: Patients with cirrhosis are at risk of both thrombotic and hemorrhagic events. Traditional hemostatic tests are inadequate to assess the complex and fragile balance of hemostasis in this setting, especially in advanced stages of disease such as decompensated cirrhosis or acute on chronic liver failure (ACLF). Furthermore, the indiscriminate use of pro-hemostatic agents for prophylaxis and treatment of bleeding episodes is still debated and often contraindicated. Alongside, splanchnic, and peripheral thrombotic events are frequent in this population and require management that involves a careful balance between risks and benefits of antithrombotic therapy. AREAS COVERED: This review aims to address the state of the art on the clinical management of the hemostatic balance of cirrhosis in terms of established knowledge and future challenges. EXPERT OPINION: The old paradigm of cirrhosis as a naturally anticoagulated condition has been challenged by more sophisticated global tests of hemostasis. Integrating this information in the clinical decision-making is still challenging for physicians and experts in hemostasis.

Clinical and genetic determinants of the fatty liver-coagulation balance interplay in individuals with metabolic dysfunction.

Background & Aims: The aim of this study was to examine the determinants of the interplay between liver damage and the coagulation balance in individuals at risk of non-alcoholic fatty liver disease (NAFLD). Methods: We considered 581 healthy participants with ≥3 metabolic alterations undergoing clinical and genomic evaluation, measurement of liver stiffness (LSM) and controlled attenuation parameter (CAP) by Fibroscan, Pro-C3, coagulation balance (von Willebrand factor [vWF], factor VIII/protein C ratio [F8/PC] as the main outcome, D-dimer as marker of coagulation/fibrinolysis activation). Results: Liver fibrosis indices (both Fibrosis-4 [FIB-4] and liver stiffness measurement [LSM]), but not liver fat (CAP), were independently associated with higher F8/PC ratio (p <0.01), triggering D-dimer formation (p = 2E-21). In keeping with a causal role of liver damage in determining a procoagulant status, the main fatty liver inherited risk variant PNPLA3 p.I148M was independently associated with the F8/PC ratio (p = 0.048). Vice versa, the main determinant of the coagulation balance was ABO locus variation (p = 1E-16), through the impact on vWF (p = 8E-26). Both rs687289 ABO and factor V Leiden were independently associated with higher Pro-C3 (p <0.025), with the effect of ABO being mediated by the impact on vWF (p = 5E-10 for association with Pro-C3). Mendelian randomisation analysis was consistent with a causal association of procoagulant imbalance with heightened fibrogenesis (p = 0.001 at robust MR-Egger for Pro-C3), but not with fibrosis (for LSM; p = not significant). Conclusions: In individuals with metabolic dysfunction, liver damage severity and possibly the PNPLA3 p.I148M variant were associated with procoagulant status. Vice versa, evaluation of inherited variants in ABO and other genes influencing coagulation was consistent with a causal role of procoagulant imbalance in activation of early stages of fibrogenesis. Lay summary: In individuals with metabolic alterations at risk of metabolic fatty liver disease, there is a tendency toward heightened blood coagulation (clotting), but the cause and the impact on the progression of liver disease remain unclear. Here we show that liver damage severity and metabolic alterations, but not hepatic fat, are mainly responsible for heightened coagulation in patients with metabolic fatty liver disease. By using genetic approaches, we showed that hepatic inflammation due to lipotoxicity may favour heightened coagulation, which in turn can trigger liver fibrosis, igniting a vicious cycle that leads to progressive liver disease.

The usefulness of D-dimer as a predictive marker for mortality in patients with COVID-19 hospitalized during the first wave in Italy.

BACKGROUND: The coronavirus disease 2019 (COVID-19) presents an urgent threat to global health. Identification of predictors of poor outcomes will assist medical staff in treatment and allocating limited healthcare resources. AIMS: The primary aim was to study the value of D-dimer as a predictive marker for in-hospital mortality. METHODS: This was a cohort study. The study population consisted of hospitalized patients (age >18 years), who were diagnosed with COVID-19 based on real-time PCR at 9 hospitals during the first COVID-19 wave in Lombardy, Italy (Feb-May 2020). The primary endpoint was in-hospital mortality. Information was obtained from patient records. Statistical analyses were performed using a Fine-Gray competing risk survival model. Model discrimination was assessed using Harrell's C-index and model calibration was assessed using a calibration plot. RESULTS: Out of 1049 patients, 507 patients (46%) had evaluable data. Of these 507 patients, 96 died within 30 days. The cumulative incidence of in-hospital mortality within 30 days was 19% (95CI: 16%-23%), and the majority of deaths occurred within the first 10 days. A prediction model containing D-dimer as the only predictor had a C-index of 0.66 (95%CI: 0.61-0.71). Overall calibration of the model was very poor. The addition of D-dimer to a model containing age, sex and co-morbidities as predictors did not lead to any meaningful improvement in either the C-index or the calibration plot. CONCLUSION: The predictive value of D-dimer alone was moderate, and the addition of D-dimer to a simple model containing basic clinical characteristics did not lead to any improvement in model performance.

External validation of risk scores to predict in-hospital mortality in patients hospitalized due to coronavirus disease 2019.

BACKGROUND: The coronavirus disease 2019 (COVID-19) presents an urgent threat to global health. Prediction models that accurately estimate mortality risk in hospitalized patients could assist medical staff in treatment and allocating limited resources. AIMS: To externally validate two promising previously published risk scores that predict in-hospital mortality among hospitalized COVID-19 patients. METHODS: Two prospective cohorts were available; a cohort of 1028 patients admitted to one of nine hospitals in Lombardy, Italy (the Lombardy cohort) and a cohort of 432 patients admitted to a hospital in Leiden, the Netherlands (the Leiden cohort). The endpoint was in-hospital mortality. All patients were adult and tested COVID-19 PCR-positive. Model discrimination and calibration were assessed. RESULTS: The C-statistic of the 4C mortality score was good in the Lombardy cohort (0.85, 95CI: 0.82-0.89) and in the Leiden cohort (0.87, 95CI: 0.80-0.94). Model calibration was acceptable in the Lombardy cohort but poor in the Leiden cohort due to the model systematically overpredicting the mortality risk for all patients. The C-statistic of the CURB-65 score was good in the Lombardy cohort (0.80, 95CI: 0.75-0.85) and in the Leiden cohort (0.82, 95CI: 0.76-0.88). The mortality rate in the CURB-65 development cohort was much lower than the mortality rate in the Lombardy cohort. A similar but less pronounced trend was found for patients in the Leiden cohort. CONCLUSION: Although performances did not differ greatly, the 4C mortality score showed the best performance. However, because of quickly changing circumstances, model recalibration may be necessary before using the 4C mortality score.