KWKoos de Wit

Koos de Wit

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


Koos de Wit has a total of 134 co-authors. Here are the top co-authors by number of shared publications:

  • Robert Bart Takkenberg

    Department of Gastroenterology and Hepatology, Amsterdam University Medical Center, Amsterdam, The Netherlands

    6 shared publications
  • Carlo Alessandria

    Division of Gastroenterology and Hepatology, Azienda Ospedaliero Universitaria Città della Salute e della Scienza di Torino, Torino, Italy

    4 shared publications
  • Elisa Pose

    Liver Unit, Hospital Clínic de Barcelona, Barcelona, Spain

    4 shared publications
  • Pere Ginès

    Liver Unit, Hospital Clínic de Barcelona, Barcelona, Spain

    4 shared publications
  • Ulrich Beuers

    Gastroenterology & Hepatology, Amsterdam University Medical Centres, Amsterdam, The Netherlands

    4 shared publications
  • Daniela Campion

    Division of Gastroenterology and Hepatology, Azienda Ospedaliero Universitaria Città della Salute e della Scienza di Torino, Torino, Italy

    3 shared publications

Latest Publications

  • Open Access

    Rifaximin‐α in Patients With Recurrent Episodes of Hepatic Encephalopathy Due to Cirrhosis Reduces Healthcare Utilization

    by Diederick J. van Doorn, Kirsi. M. A. van Eekhout, Koos de Wit, L. C. Baak, Michael Klemt‐Kropp, Bart J. Verwer, Philip Friederich, Gijs J. de Bruin, Xander G. Vos, Joost P. H. Drenth, et al.

    Background and Aims: Hepatic encephalopathy is a frequent complication of cirrhosis. Rifaximin‐α has been included in guidelines for secondary prevention of hepatic encephalopathy, but there are few real‐world data on its efficacy and impact on healthcare utilization. In this study, we aimed to assess the effect of rifaximin‐α on healthcare utilization.Method: We conducted a cohort analysis in patients from seven hospitals in the Netherlands, who received rifaximin‐α as secondary prophylaxis for hepatic encephalopathy. Data were compared 6 months before and 6 months after the prescription of rifaximin‐α. The primary endpoint was the effect of rifaximin‐α on healthcare utilization. Secondary endpoint was the effect of rifaximin‐α on healthcare costs.Results: We included 126 patients (65% male; median age 68) with a median Model for End‐stage Liver Disease score of 15. The mean number of hepatic encephalopathy episodes after starting rifaximin‐α was lower than before starting rifaximin‐α (0.9 vs. 2.2; p < 0.001). Mean healthcare utilization decreased from 6.1 contacts in the 6 months before rifaximin‐α to 3.3 contacts in the 6 months after starting rifaximin‐α (p < 0.001). The mean number of hospital admissions decreased from 1.7 admissions per patient to 1.0 admissions after starting rifaximin‐α (p < 0.001). The mean number of outpatient visits also decreased after starting rifaximin‐α (2.4 visits per patient to 1.7; p = 0.001). Annual costs per patient before starting rifaximin‐α were €13,320. This was similar to the costs after rifaximin‐α was prescribed (€13,120).Conclusion: Rifaximin‐α significantly reduced the number of episodes of hepatic encephalopathy, the number of hospital admissions as well as the number of outpatient and emergency department visits, contributing to a reduction in healthcare utilization. There was no reduction in overall costs.


  • Novel prognostic biomarkers in decompensated cirrhosis: a systematic review and meta-analysis

    by Adrià Juanola, Ann Thu Ma, Koos de Wit, Kohilan Gananandan, Olivier Roux, Giacomo Zaccherini, César Jiménez, Marta Tonon, Cristina Solé, Clara Villaseca, et al.

    Background Patients with decompensated cirrhosis experience high mortality rates. Current prognostic scores, including the model for end-stage liver disease (MELD), may underperform in settings other than in those they were initially developed. Novel biomarkers have been proposed to improve prognostication accuracy and even to predict development of complications. Methods We performed a systematic review and meta-analysis on novel urine and blood biomarkers and their ability to predict 90-day mortality in patients with decompensated cirrhosis. Secondary outcomes included 28-day and 1-year mortality, and development of acute-on-chronic liver failure, acute kidney injury and other complications. To overcome differences in units, temporal changes in assays and reporting heterogeneity, we used the ratio of means (RoM) as measure of association for assessing strength in predicting outcomes. An RoM>1 implies that the mean biomarker level is higher in those that develop the outcome than in those that do not. Results Of 6629 unique references, 103 were included, reporting on 29 different biomarkers, with a total of 31 362 biomarker patients. Most studies were prospective cohorts of hospitalised patients (median Child-Pugh-Turcotte score of 9 and MELD score of 18). The pooled 90-day mortality rate was 0.27 (95% CI 0.24 to 0.29). The RoM for predicting 90-day mortality was highest for interleukin 6 (IL-6) (2.56, 95% CI 2.39 to 2.74), followed by urinary neutrophil gelatinase-associated lipocalin (uNGAL) (2.42, 95% CI 2.20 to 2.66) and copeptin (2.33, 95% CI 2.17 to 2.50). These RoMs were all higher than for MELD (1.44, 95% CI 1.42 to 1.46). Conclusion Novel biomarkers, including IL-6, uNGAL and copeptin, can probably improve prognostication of patients with decompensated cirrhosis compared with MELD alone.


  • Open Access

    Opt-In and Opt-Out Consent Procedures for the Reuse of Routinely Recorded Health Data in Scientific Research and Their Consequences for Consent Rate and Consent Bias: Systematic Review

    by Yvonne de Man, Yvonne Wieland-Jorna, Bart Torensma, Koos de Wit, Anneke L Francke, Mariska G Oosterveld-Vlug, Robert A Verheij

    Background: Scientific researchers who wish to reuse health data pertaining to individuals can obtain consent through an opt-in procedure or opt-out procedure. The choice of procedure may have consequences for the consent rate and representativeness of the study sample and the quality of the research, but these consequences are not well known. Objective: This review aimed to provide insight into the consequences for the consent rate and consent bias of the study sample of opt-in procedures versus opt-out procedures for the reuse of routinely recorded health data for scientific research purposes. Methods: A systematic review was performed based on searches in PubMed, Embase, CINAHL, PsycINFO, Web of Science Core Collection, and the Cochrane Library. Two reviewers independently included studies based on predefined eligibility criteria and assessed whether the statistical methods used in the reviewed literature were appropriate for describing the differences between consenters and nonconsenters. Statistical pooling was conducted, and a description of the results was provided. Results: A total of 15 studies were included in this meta-analysis. Of the 15 studies, 13 (87%) implemented an opt-in procedure, 1 (7%) implemented an opt-out procedure, and 1 (7%) implemented both the procedures. The average weighted consent rate was 84% (60,800/72,418 among the studies that used an opt-in procedure and 96.8% (2384/2463) in the single study that used an opt-out procedure. In the single study that described both procedures, the consent rate was 21% in the opt-in group and 95.6% in the opt-out group. Opt-in procedures resulted in more consent bias compared with opt-out procedures. In studies with an opt-in procedure, consenting individuals were more likely to be males, had a higher level of education, higher income, and higher socioeconomic status. Conclusions: Consent rates are generally lower when using an opt-in procedure compared with using an opt-out procedure. Furthermore, in studies with an opt-in procedure, participants are less representative of the study population. However, both the study populations and the way in which opt-in or opt-out procedures were organized varied widely between the studies, which makes it difficult to draw general conclusions regarding the desired balance between patient control over data and learning from health data. The reuse of routinely recorded health data for scientific research purposes may be hampered by administrative burdens and the risk of bias.


  • Open Access

    Issue Cover

    by Koos de Wit, Ulrich Beuers, Anna Mukha, Edwin C. A. Stigter, M. Can Gulersonmez, Jose M. Ramos Pittol, Sabine Middendorp, R. Bart Takkenberg, Saskia W. C. van Mil

  • Open Access

    Decompensation as initial presentation in patients with liver cirrhosis is associated with an increased risk of future decompensation and mortality

    by Koos de Wit, Thijs Kuipers, Koen Van der Ploeg, Lubbertus C. Baak, Ulrich Beuers, R. Bart Takkenberg

    The clinical course of patients with liver cirrhosis and adherence to hepatocellular carcinoma (HCC) screening guidelines are not well studied in the Netherlands. We investigated this and potential...


  • Open Access

    Rifaximin stimulates nitrogen detoxification by PXR‐independent mechanisms in human small intestinal organoids

    by Koos de Wit, Ulrich Beuers, Anna Mukha, Edwin C. A. Stigter, M. Can Gulersonmez, Jose M. Ramos Pittol, Sabine Middendorp, R. Bart Takkenberg, Saskia W. C. van Mil

    Background and Aims: Recurrent hepatic encephalopathy (HE) is characterized by hyperammonaemia in combination with neuropsychiatric abnormalities and is treated with lactulose and rifaximin. Rifaximin is a pregnane X receptor (PXR) agonist with low systemic and high intestinal bioavailability. The mechanisms by which it alleviates HE are unclear. We used human small intestinal (hSI) organoids to study whether rifaximin, via PXR activation, affects the epithelial biotransformation machinery, and to gain understanding of its low systemic availability.Methods: We generated PXR knockdown hSI organoids via lentiviral delivery of short hairpin RNAs. Organoids were cultured for 24 h with rifaximin or rifampicin. RNA‐sequencing and metabolomics were performed to analyse gene expression and amino acid metabolism. Luminal rifaximin was quantified by photospectrometry.Results: Treatment of wild‐type hSI organoids with rifaximin resulted in >twofold differential expression of 131 genes compared to DMSO. These effects were largely PXR independent and related to amino acid metabolism. Rifaximin decreased expression of glutaminase‐2 and increased expression of asparagine synthetase and solute carrier 7A11, thereby increasing intracellular glutamine and asparagine concentrations, indicating active ammonia detoxification. Rifaximin was apically excreted into the lumen in an ATP binding cassette B1 (ABCB1)‐dependent manner.Conclusions: Rifaximin—after uptake into enterocytes—stimulates intracellular nitrogen detoxification by PXR‐independent mechanisms. Active apical excretion of rifaximin by ABCB1 into the intestinal lumen explains its low systemic bioavailability. Our study implies that rifaximin, next to modulation of the microbiome, has direct effects on ammonia scavenging in the human small intestinal epithelium.


  • Open Access

    Opt-In and Opt-Out Consent Procedures for the Reuse of Routinely Recorded Health Data in Scientific Research and Their Consequences for Consent Rate and Consent Bias: Systematic Review (Preprint)

    by Yvonne de Man, Yvonne Wieland-Jorna, Bart Torensma, Koos de Wit, Anneke L Francke, Mariska G Oosterveld-Vlug, Robert A Verheij

    Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet #Preprint #PeerReviewMe: Warning: This is a unreviewed preprint. Readers are warned that the document has not been peer-reviewed by expert/patient reviewers or an academic editor, may contain misleading claims, and is likely to undergo changes before final publication, if accepted, or may have been rejected/withdrawn. Readers with interest and expertise are encouraged to sign up as peer-reviewer, if the paper is within an open peer-review period. Please cite this preprint only for review purposes or for grant applications and CVs (if you are the author). Background: Scientific researchers who wish to reuse health data pertaining to individuals can obtain consent through an opt-in procedure or opt-out procedure. The choice of procedure may have consequences for the consent rate and representativeness of the study sample and the quality of the research, but these consequences are not well known. Objective: This review aimed to provide insight into the consequences for the consent rate and consent bias of the study sample of opt-in procedures versus opt-out procedures for the reuse of routinely recorded health data for scientific research purposes. Methods: A systematic review was performed based on searches in PubMed, Embase, CINAHL, PsycINFO, Web of Science Core Collection, and the Cochrane Library. Two reviewers independently included studies based on predefined eligibility criteria and assessed whether the statistical methods used in the reviewed literature were appropriate for describing the differences between consenters and nonconsenters. Statistical pooling was conducted, and a description of the results was provided. Results: A total of 15 studies were included in this meta-analysis. Of the 15 studies, 13 (87%) implemented an opt-in procedure, 1 (7%) implemented an opt-out procedure, and 1 (7%) implemented both the procedures. The average weighted consent rate was 84% (60,800/72,418 among the studies that used an opt-in procedure and 96.8% (2384/2463) in the single study that used an opt-out procedure. In the single study that described both procedures, the consent rate was 21% in the opt-in group and 95.6% in the opt-out group. Opt-in procedures resulted in more consent bias compared with opt-out procedures. In studies with an opt-in procedure, consenting individuals were more likely to be males, had a higher level of education, higher income, and higher socioeconomic status. Conclusions: Consent rates are generally lower when using an opt-in procedure compared with using an opt-out procedure. Furthermore, in studies with an opt-in procedure, participants are less representative of the study population. However, both the study populations and the way in which opt-in or opt-out procedures were organized varied widely between the studies, which makes it difficult to draw general conclusions regarding the desired balance between patient control over data and learning from health data. The reuse of routinely recorded health data for scientific research purposes may be hampered by administrative burdens and the risk of bias.

  • Open Access

    Treatment With Simvastatin and Rifaximin Restores the Plasma Metabolomic Profile in Patients With Decompensated Cirrhosis

    by Elisa Pose, Elsa Solà, Juan J. Lozano, Adrià Juanola, Julia Sidorova, Giacomo Zaccherini, Koos de Wit, Frank Uschner, Marta Tonon, Konstantin Kazankov, et al.

    Patients with decompensated cirrhosis, particularly those with acute‐on‐chronic liver failure (ACLF), show profound alterations in plasma metabolomics. The aim of this study was to investigate the effect of treatment with simvastatin and rifaximin on plasma metabolites of patients with decompensated cirrhosis, specifically on compounds characteristic of the ACLF plasma metabolomic profile. Two cohorts of patients were investigated. The first was a descriptive cohort of patients with decompensated cirrhosis (n = 42), with and without ACLF. The second was an intervention cohort from the LIVERHOPE‐SAFETY randomized, double‐blind, placebo‐controlled trial treated with simvastatin 20 mg/day plus rifaximin 1,200 mg/day (n = 12) or matching placebo (n = 13) for 3 months. Plasma samples were analyzed using ultrahigh performance liquid chromatography–tandem mass spectroscopy for plasma metabolomics characterization. ACLF was characterized by intense proteolysis and lipid alterations, specifically in pathways associated with inflammation and mitochondrial dysfunction, such as the tryptophan–kynurenine and carnitine beta‐oxidation pathways. An ACLF‐specific signature was identified. Treatment with simvastatin and rifaximin was associated with changes in 161 of 985 metabolites in comparison to treatment with placebo. A remarkable reduction in levels of metabolites from the tryptophan–kynurenine and carnitine pathways was found. Notably, 18 of the 32 metabolites of the ACLF signature were affected by the treatment. Conclusion: Treatment with simvastatin and rifaximin modulates some of the pathways that appear to be key in ACLF development. This study unveils some of the mechanisms involved in the effects of treatment with simvastatin and rifaximin in decompensated cirrhosis and sets the stage for the use of metabolomics to investigate new targeted therapies in cirrhosis to prevent ACLF development.


  • Open Access

    The Use of Rifaximin in Patients With Cirrhosis

    by Paolo Caraceni, Victor Vargas, Elsa Solà, Carlo Alessandria, Koos de Wit, Jonel Trebicka, Paolo Angeli, Rajeshwar P. Mookerjee, François Durand, Elisa Pose, et al.

    Rifaximin is an oral nonsystemic antibiotic with minimal gastrointestinal absorption and broad‐spectrum antibacterial activity covering both gram‐positive and gram‐negative organisms. Rifaximin is currently used worldwide in patients with cirrhosis for preventing recurrent HE because its efficacy and safety have been proven by large randomized clinical trials. In the last decade, experimental and clinical evidence suggest that rifaximin could have other beneficial effects on the course of cirrhosis by modulating the gut microbiome and affecting the gut‐liver axis, which in turn can interfere with major events of the pathophysiological cascade underlying decompensated cirrhosis, such as systemic inflammatory syndrome, portal hypertension, and bacterial infections. However, the use of rifaximin for prevention or treatment of other complications, including spontaneous bacterial peritonitis or other bacterial infections, is not accepted because evidence by clinical trials is still very weak. The present review deals in the first part with the potential impact of rifaximin on pathogenic mechanisms in liver diseases, whereas in the second part, its clinical effects are critically discussed. It clearly emerges that, because of its potential activity on multiple pathogenic events, the efficacy of rifaximin in the prevention or management of complications other than HE deserves to be investigated extensively. The results of double‐blinded, adequately powered randomized clinical trials assessing the effect of rifaximin, alone or in combination with other drugs, on hard clinical endpoints, such as decompensation of cirrhosis, acute‐on‐chronic liver failure, and mortality, are therefore eagerly awaited.