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Dive into the research topics where Gert Jan van der Wilt is active.

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Featured researches published by Gert Jan van der Wilt.


The Lancet | 2001

Cognitive behaviour therapy for chronic fatigue syndrome: a multicentre randomised controlled trial

J.B. Prins; Gijs Bleijenberg; Ellen Bazelmans; L.D. Elving; Theo de Boo; Johan L. Severens; Gert Jan van der Wilt; Philip Spinhoven; Jos W. M. van der Meer

BACKGROUND Cognitive behaviour therapy (CBT) seems a promising treatment for chronic fatigue syndrome (CFS), but the applicability of this treatment outside specialised settings has been questioned. We compared CBT with guided support groups and the natural course in a randomised trial at three centres. METHODS Of 476 patients diagnosed with CFS, 278 were eligible and willing to take part. 93 were randomly assigned CBT (administered by 13 therapists recently trained in this technique for CFS), 94 were assigned the support-group approach, and 91 the control natural course. Multidimensional assessments were done at baseline, 8 months, and 14 months. The primary outcome variables were fatigue severity (on the checklist individual strength) and functional impairment (on the sickness impact profile) at 8 and 14 months. Data were analysed by intention to treat. FINDINGS 241 patients had complete data (83 CBT, 80 support groups, 78 natural course) at 8 months. At 14 months CBT was significantly more effective than both control conditions for fatigue severity (CBT vs support groups 5.8 [2.2-9.4]; CBT vs natural course 5.6 [2.1-9.0]) and for functional impairment (CBT vs support groups 263 [38-488]; CBT vs natural course 222 [3-441]). Support groups were not more effective for CFS patients than the natural course. Among the CBT group, clinically significant improvement was seen in fatigue severity for 20 of 58 (35%), in Karnofsky performance status for 28 of 57 (49%), and self-rated improvement for 29 of 58 (50%). Prognostic factors for outcome after CBT were a higher sense of control predicting more improvement, and a passive activity pattern and focusing on bodily symptoms predicting less improvement. INTERPRETATION CBT was more effective than guided support groups and the natural course in a multicentre trial with many therapists. Our study showed a lower proportion of patients with improvement than CBT trials with a few highly skilled therapists.


Arthritis & Rheumatism | 2001

Effect of folic or folinic acid supplementation on the toxicity and efficacy of methotrexate in rheumatoid arthritis: a forty-eight week, multicenter, randomized, double-blind, placebo-controlled study

Annelies E. van Ede; R.F.J.M. Laan; Maarten J. Rood; Tom W J Huizinga; Mart A F J van de Laar; Christiaan van Denderen; Toon Westgeest; Ton C. Romme; Dirk-Jan R.A.M. de Rooij; Marike J. M. Jacobs; Theo de Boo; Gert Jan van der Wilt; Johan L. Severens; Margriet Hartman; Paul F. M. Krabbe; Ben A. C. Dijkmans; Ferdinand C. Breedveld; Leo B. A. Van De Putte

OBJECTIVE To study the effect of folates on discontinuation of methotrexate (MTX) as single-drug antirheumatic treatment due to toxicity, to determine which type of adverse events are reduced, to study the effects on the efficacy of MTX, and to compare folic with folinic acid supplementation in a 48-week, randomized, double-blind, placebo-controlled trial. METHODS Patients with active RA (n = 434) were randomly assigned to receive MTX plus either placebo, folic acid (1 mg/day), or folinic acid (2.5 mg/week). The initial MTX dosage was 7.5 mg/week; dosage increases were allowed up to a maximum of 25 mg/week for insufficient responses. Folate dosages were doubled once the dosage of MTX reached 15 mg/week. The primary end point was MTX withdrawal because of adverse events. Secondary end points were the MTX dosage and parameters of efficacy and toxicity of MTX. RESULTS Toxicity-related discontinuation of MTX occurred in 38% of the placebo group, 17% of the folic acid group, and 12% of the folinic acid group. These between-group differences were explained by a decreased incidence of elevated liver enzyme levels in the folate supplementation groups. No between-group differences were found in the frequency of other adverse events or in the duration of adverse events. Parameters of disease activity improved equally in all groups. Mean dosages of MTX at the end of the study were lower in the placebo group (14.5 mg/week) than in the folic and folinic acid groups (18.0 and 16.4 mg/week, respectively). CONCLUSION Both folate supplementation regimens reduced the incidence of elevated liver enzyme levels during MTX therapy, and as a consequence, MTX was discontinued less frequently in these patients. Folates seem to have no effect on the incidence, severity, and duration of other adverse events, including gastrointestinal and mucosal side effects. Slightly higher dosages of MTX were prescribed to obtain similar improvement in disease activity in the folate supplementation groups.


BMJ | 2006

Comparison of laparoscopic and mini incision open donor nephrectomy: single blind, randomised controlled clinical trial.

Niels F.M. Kok; May Y. Lind; Birgitta M E Hansson; Desiree Pilzecker; Ingrid R.A.M. Mertens Zur Borg; Ben C Knipscheer; Eric J. Hazebroek; Ine M. M. Dooper; Willem Weimar; Wim C. J. Hop; E.M.M. Adang; Gert Jan van der Wilt; H. J. Bonjer; Jordanus A van der Vliet; Jan N. M. IJzermans

Abstract Objectives To determine the best approach for live donor nephrectomy to minimise discomfort to the donor and to provide good graft function. Design Single blind, randomised controlled trial. Setting Two university medical centres, the Netherlands. Participants 100 living kidney donors. Interventions Participants were randomly assigned to either laparoscopic donor nephrectomy or to mini incision muscle splitting open donor nephrectomy. Main outcome measures The primary outcome was physical fatigue using the multidimensional fatigue inventory 20 (MFI-20). Secondary outcomes were physical function using the SF-36, hospital stay after surgery, pain, operating times, recipient graft function, and graft survival. Results Conversions did not occur. Compared with mini incision open donor nephrectomy, laparoscopic donor nephrectomy resulted in longer skin to skin time (median 221 v 164 minutes, P < 0.001), longer warm ischaemia time (6 v 3 minutes, P < 0.001), less blood loss (100 v 240 ml, P < 0.001), and a similar number of complications (intraoperatively 12% v 6%, P = 0.49, postoperatively both 6%). After laparoscopic nephrectomy, donors required less morphine (16 v 25 mg, P = 0.005) and shorter hospital stay (3 v 4 days, P = 0.003). During one years follow-up mean physical fatigue was less (difference - 1.3, 95% confidence interval - 2.4 to - 0.1) and physical function was better (difference 6.2, 2.0 to 10.3) after laparoscopic nephrectomy. Function of the graft and graft survival rate of the recipient at one year censored for death did not differ (100% after laparoscopic nephrectomy and 98% after open nephrectomy). Conclusions Laparoscopic donor nephrectomy results in a better quality of life compared with mini incision open donor nephrectomy but equal safety and graft function.


Annals of Surgical Oncology | 2005

Can the Memorial Sloan-Kettering Cancer Center Nomogram Predict the Likelihood of Nonsentinel Lymph Node Metastases in Breast Cancer Patients in The Netherlands?

Marjolein L. Smidt; Deborah M. Kuster; Gert Jan van der Wilt; Frederik B. Thunnissen; Kimberley J. Van Zee; L.J.A. Strobbe

BackgroundAccording to Dutch guidelines, an axillary lymph node dissection (ALND) is recommended whenever a sentinel lymph node (SLN) contains metastatic disease. However, only in approximately 50% of patients with metastatic disease in the SLN are additional nodal metastases detected in the completion ALND. To identify the individual patient’s risk for non-SLN metastases, a nomogram containing eight predictors was developed by the Breast Service of Memorial Sloan-Kettering Cancer Center (New York, NY). The aim of this study was to test the accuracy of the nomogram on a population of Dutch breast cancer patients.MethodsPatient, tumor, and SLN metastasis characteristics were collected for 222 consecutive patients who underwent a completion ALND. The data of the index and test populations were compared. A receiver operating characteristic curve was drawn, and the area under the curve was calculated to assess the discriminative power of the nomogram.ResultsEven though our patient population differed in many respects from the source population, the area under the receiver operating characteristic curve amounted to .77, a value very much comparable to the one found in the source population.ConclusionsThe nomogram provides a fairly accurate predicted probability for the likelihood of non-SLN metastases in a general population of breast cancer patients at a regional teaching hospital in The Netherlands. This suggests that the nomogram’s originally calculated predictive accuracy may be valid for patient populations that differ considerably from the population in which it was developed.


Digestive Surgery | 2013

Guidelines of Diagnostics and Treatment of Acute Left-Sided Colonic Diverticulitis

Caroline S. Andeweg; Irene M. Mulder; Richelle J. F. Felt-Bersma; Annelies Verbon; Gert Jan van der Wilt; Harry van Goor; Johan F. Lange; Jaap Stoker; Marja A. Boermeester; Robert P. Bleichrodt

Background: The incidence of acute left-sided colonic diverticulitis (ACD) is increasing in the Western world. To improve the quality of patient care, a guideline for diagnosis and treatment of diverticulitis is needed. Methods: A multidisciplinary working group, representing experts of relevant specialties, was involved in the guideline development. A systematic literature search was conducted to collect scientific evidence on epidemiology, classification, diagnostics and treatment of diverticulitis. Literature was assessed using the classification system according to an evidence-based guideline development method, and levels of evidence of the conclusions were assigned to each topic. Final recommendations were given, taking into account the level of evidence of the conclusions and other relevant considerations such as patient preferences, costs and availability of facilities. Results: The natural history of diverticulitis is usually mild and treatment is mostly conservative. Although younger patients have a higher risk of recurrent disease, a higher risk of complications compared to older patients was not found. In general, the clinical diagnosis of ACD is not accurate enough and therefore imaging is indicated. The triad of pain in the lower left abdomen on physical examination, the absence of vomiting and a C-reactive protein >50 mg/l has a high predictive value to diagnose ACD. If this triad is present and there are no signs of complicated disease, patients may be withheld from further imaging. If imaging is indicated, conditional computed tomography, only after a negative or inconclusive ultrasound, gives the best results. There is no indication for routine endoscopic examination after an episode of diverticulitis. There is no evidence for the routine administration of antibiotics in patients with clinically mild uncomplicated diverticulitis. Treatment of pericolic or pelvic abscesses can initially be treated with antibiotic therapy or combined with percutaneous drainage. If this treatment fails, surgical drainage is required. Patients with a perforated ACD resulting in peritonitis should undergo an emergency operation. There is an ongoing debate about the optimal surgical strategy. Conclusion: Scientific evidence is scarce for some aspects of ACD treatment (e.g. natural history of ACD, ACD in special patient groups, prevention of ACD, treatment of uncomplicated ACD and medical treatment of recurrent ACD), leading to treatment being guided by the surgeons personal preference. Other aspects of the management of patients with ACD have been more thoroughly researched (e.g. imaging techniques, treatment of complicated ACD and elective surgery of ACD). This guideline of the diagnostics and treatment of ACD can be used as a reference for clinicians who treat patients with ACD.


Laboratory Animals | 2012

A step-by-step guide to systematically identify all relevant animal studies.

Marlies Leenaars; Carlijn R. Hooijmans; Nieky van Veggel; Gerben ter Riet; M.M.G. Leeflang; Lotty Hooft; Gert Jan van der Wilt; Alice Tillema; Merel Ritskes-Hoitinga

Before starting a new animal experiment, thorough analysis of previously performed experiments is essential from a scientific as well as from an ethical point of view. The method that is most suitable to carry out such a thorough analysis of the literature is a systematic review (SR). An essential first step in an SR is to search and find all potentially relevant studies. It is important to include all available evidence in an SR to minimize bias and reduce hampered interpretation of experimental outcomes. Despite the recent development of search filters to find animal studies in PubMed and EMBASE, searching for all available animal studies remains a challenge. Available guidelines from the clinical field cannot be copied directly to the situation within animal research, and although there are plenty of books and courses on searching the literature, there is no compact guide available to search and find relevant animal studies. Therefore, in order to facilitate a structured, thorough and transparent search for animal studies (in both preclinical and fundamental science), an easy-to-use, step-by-step guide was prepared and optimized using feedback from scientists in the field of animal experimentation. The step-by-step guide will assist scientists in performing a comprehensive literature search and, consequently, improve the scientific quality of the resulting review and prevent unnecessary animal use in the future.


The Lancet Diabetes & Endocrinology | 2016

Adrenal vein sampling versus CT scan to determine treatment in primary aldosteronism: an outcome-based randomised diagnostic trial

Tanja Dekkers; Aleksander Prejbisz; Leo J. Schultze Kool; Hans Groenewoud; M. Velema; Wilko Spiering; Sylwia Kołodziejczyk-Kruk; Mark J. Arntz; Jacek Kądziela; Johannes F Langenhuijsen; Michiel N. Kerstens; Anton H. van den Meiracker; Bert-Jan H. van den Born; Fred C.G.J. Sweep; A.R.M.M. Hermus; Andrzej Januszewicz; Alike F Ligthart-Naber; Peter Makai; Gert Jan van der Wilt; Jacques W. M. Lenders; Jaap Deinum

BACKGROUND The distinction between unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia as causes of primary aldosteronism is usually made by adrenal CT or by adrenal vein sampling (AVS). Whether CT or AVS represents the best test for diagnosis remains unknown. We aimed to compare the outcome of CT-based management with AVS-based management for patients with primary aldosteronism. METHODS In a randomised controlled trial, we randomly assigned patients with aldosteronism to undergo either adrenal CT or AVS to determine the presence of aldosterone-producing adenoma (with subsequent treatment consisting of adrenalectomy) or bilateral adrenal hyperplasia (subsequent treatment with mineralocorticoid receptor antagonists). The primary endpoint was the intensity of drug treatment for obtaining target blood pressure after 1 year of follow-up, in the intention-to-diagnose population. Intensity of drug treatment was expressed as daily defined doses. Key secondary endpoints included biochemical outcome in patients who received adrenalectomy, health-related quality of life, cost-effectiveness, and adverse events. This trial is registered with ClinicalTrials.gov, number NCT01096654. FINDINGS We recruited 200 patients between July 6, 2010, and May 30, 2013. Of the 184 patients that completed follow-up, 92 received CT-based treatment (46 adrenalectomy and 46 mineralocorticoid receptor antagonist) and 92 received AVS-based treatment (46 adrenalectomy and 46 mineralocorticoid receptor antagonist). We found no differences in the intensity of antihypertensive medication required to control blood pressure between patients with CT-based treatment and those with AVS-based treatment (median daily defined doses 3·0 [IQR 1·0-5·0] vs 3·0 [1·1-5·9], p=0·52; median number of drugs 2 [IQR 1-3] vs 2 [1-3], p=0·87). Target blood pressure was reached in 39 (42%) patients and 41 (45%) patients, respectively (p=0·82). On secondary endpoints we found no differences in health-related quality of life (median RAND-36 physical scores 52·7 [IQR 43·9-56·8] vs 53·2 [44·0-56·8], p=0·83; RAND-36 mental scores 49·8 [43·1-54·6] vs 52·7 [44·9-55·5], p=0·17) for CT-based and AVS-based treatment. Biochemically, 37 (80%) of patients with CT-based adrenalectomy and 41 (89%) of those with AVS-based adrenalectomy had resolved hyperaldosteronism (p=0·25). A non-significant mean difference of 0·05 (95% CI -0·04 to 0·13) in quality-adjusted life-years (QALYs) was found to the advantage of the AVS group, associated with a significant increase in mean health-care costs of €2285 per patient (95% CI 1323-3248). At a willingness-to-pay value of €30 000 per QALY, the probability that AVS compared with CT constitutes an efficient use of health-care resources in the diagnostic work-up of patients with primary aldosteronism is less than 0·2. There was no difference in adverse events between groups (159 events of which nine were serious vs 187 events of which 12 were serious) for CT-based and AVS-based treatment. INTERPRETATION Treatment of primary aldosteronism based on CT or AVS did not show significant differences in intensity of antihypertensive medication or clinical benefits for patients after 1 year of follow-up. This finding challenges the current recommendation to perform AVS in all patients with primary aldosteronism. FUNDING Netherlands Organisation for Health Research and Development-Medical Sciences, Institute of Cardiology, Warsaw.


Hpb | 2013

To drain or not to drain: a cumulative meta-analysis of the use of routine abdominal drains after pancreatic resection

Aart A. van der Wilt; M.M.E. Coolsen; Ignace H. de Hingh; Gert Jan van der Wilt; Hans Groenewoud; Cornelis H.C. Dejong; Ronald M. van Dam

BACKGROUND To warrant the adoption or rejection of health care interventions in daily practice, it is important to establish the point at which the available evidence is considered sufficiently conclusive. This process must avoid bias resulting from multiple testing and take account of heterogeneity across studies. The present paper addresses the issue of whether the available evidence may be considered sufficiently conclusive to continue or discontinue the current practice of postoperative abdominal drainage after pancreatic resection. METHODS A systematic review was conducted of randomized and non-randomized studies comparing outcomes after routine intra-abdominal drainage with those after no drainage after pancreatic resection. Studies were retrieved from the PubMed, Cochrane Central Trial Register and EMBASE databases and meta-analysed cumulatively, adjusting for multiple testing and heterogeneity using the iterated logarithm method. RESULTS Three reports, describing, respectively, one randomized and two non-randomized studies with a comparative design, met the inclusion criteria predefined for primary studies reporting on drain management and complications after pancreatic resection. These studies included 89, 179 and 226 patients, respectively. The absolute differences in rates of postoperative complications in these studies were -6.4%, -9.5% and -6.3%, respectively, in favour of the no-drain groups. The cumulative risk difference in major complications, adjusted for multiple testing and heterogeneity, was -7.8%, with a 95% confidence interval of -20.2% to 4.7% (P = 0.214). CONCLUSIONS The routine use of abdominal drains after pancreatic resection may result in a higher risk for major complications, but the evidence is inconclusive.


International Journal of Technology Assessment in Health Care | 1999

ECONOMIC EVALUATION OF DIAGNOSTIC TESTS

Johan L. Severens; Gert Jan van der Wilt

Objectives: The purpose of this review was to examine whether studies from the medical literature focusing on efficiency of diagnostic facilities reported economic evaluation methods appropriately, following guidelines for conducting and reporting economic evaluations. Methods: A Medline search was conducted, and studies that concerned a diagnostic technology and fulfilled the Drummond criteria were selected for methodological review. The reliability of selection and methodological review based on the abstracts was determined by scoring a random sample of both abstracts and full articles. lnterrater reliability was determined by scoring a random sample of abstracts by both authors. Kappa values were calculated. Nine methodological aspects were reviewed: study design, the type of economic evaluation, the comparison made, the studys perspective, the cost-effectiveness ratio used, the definition of cost-effective, the types of costs analyzed, the cost calculation method, and the use of sensitivity analysis. Results: Two hundred fifty studies published between 1992 and 1997 were found regarding efficiency of diagnosticfacilities; 134 studiesfulfilled the Drummond criteriaand were selected for methodological review. Kappavalues showed reliability of selection and methodological review and interrater reliability. The existing literatue on the economic evaluation of diagnostic facilities does not adhere well to guidelines for economic evaluation. In 95%, no perspective was mentioned, in 50% of the cases no ratio was given, in 82% the cost calculation method was not mentioned, and in 66% no sensitivity analysis was reported. Conclusions: Our review suggests that to improve the quality of reporting economic evaluations, editorial boards could issue and enforce guidelines for standard reporting of such studies.


BMC Psychiatry | 2012

Preventing relapse in recurrent depression using mindfulness-based cognitive therapy, antidepressant medication or the combination: trial design and protocol of the MOMENT study

Marloes J. Huijbers; J. Spijker; A. Rogier T. Donders; Digna J. F. van Schaik; Patricia van Oppen; Henricus G. Ruhé; Marc Blom; Willem A. Nolen; Johan Ormel; Gert Jan van der Wilt; Willem Kuyken; Philip Spinhoven; Anne Speckens

BackgroundDepression is a common psychiatric disorder characterized by a high rate of relapse and recurrence. The most commonly used strategy to prevent relapse/recurrence is maintenance treatment with antidepressant medication (mADM). Recently, it has been shown that Mindfulness-Based Cognitive Therapy (MBCT) is at least as effective as mADM in reducing the relapse/recurrence risk. However, it is not yet known whether combination treatment of MBCT and mADM is more effective than either of these treatments alone. Given the fact that most patients have a preference for either mADM or for MBCT, the aim of the present study is to answer the following questions. First, what is the effectiveness of MBCT in addition to mADM? Second, how large is the risk of relapse/recurrence in patients withdrawing from mADM after participating in MBCT, compared to those who continue to use mADM after MBCT?Methods/designTwo parallel-group, multi-center randomized controlled trials are conducted. Adult patients with a history of depression (3 or more episodes), currently either in full or partial remission and currently treated with mADM (6 months or longer) are recruited. In the first trial, we compare mADM on its own with mADM plus MBCT. In the second trial, we compare MBCT on its own, including tapering of mADM, with mADM plus MBCT. Follow-up assessments are administered at 3-month intervals for 15 months. Primary outcome is relapse/recurrence. Secondary outcomes are time to, duration and severity of relapse/recurrence, quality of life, personality, several process variables, and incremental cost-effectiveness ratio.DiscussionTaking into account patient preferences, this study will provide information about a) the clinical and cost-effectiveness of mADM only compared with mADM plus MBCT, in patients with a preference for mADM, and b) the clinical and cost-effectiveness of withdrawing from mADM after MBCT, compared with mADM plus MBCT, in patients with a preference for MBCT.Trial registrationClinicalTrials.gov: NCT00928980

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Marcia Tummers

Radboud University Nijmegen

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Gerhard A. Zielhuis

Radboud University Nijmegen Medical Centre

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Jaap Deinum

Radboud University Nijmegen

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John Grin

University of Amsterdam

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Gea Drost

University Medical Center Groningen

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