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Dive into the research topics where Martijn G. van Oijen is active.

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Featured researches published by Martijn G. van Oijen.


Gastroenterology | 2008

Random comparison of guaiac and immunochemical fecal occult blood tests for colorectal cancer in a screening population

Leo G.M. van Rossum; Anne F. van Rijn; Robert J.F. Laheij; Martijn G. van Oijen; Paul Fockens; Han J.H. van Krieken; A.L.M. Verbeek; Jan Bmj Jansen; Evelien Dekker

BACKGROUND & AIMS Despite poor performance, guaiac-based fecal occult blood tests (G-FOBT) are most frequently implemented for colorectal cancer screening. Immunochemical fecal occult blood tests (I-FOBT) are claimed to perform better, without randomized comparison in screening populations. Our aim was to randomly compare G-FOBT with I-FOBT in a screening population. METHODS We conducted a population-based study on a random sample of 20,623 individuals 50-75 years of age, randomized to either G-FOBT (Hemoccult-II) or I-FOBT (OC-Sensor). Tests and invitations were sent together. For I-FOBT, the standard cutoff of 100 ng/ml was used. Positive FOBTs were verified with colonoscopy. Advanced adenomas were defined as >or=10 mm, high-grade dysplasia, or >or=20% villous component. RESULTS There were 10,993 tests returned: 4836 (46.9%) G-FOBTs and 6157 (59.6%) I-FOBTs. The participation rate difference was 12.7% (P < .01). Of G-FOBTs, 117 (2.4%) were positive versus 339 (5.5%) of I-FOBTs. The positivity rate difference was 3.1% (P < .01). Cancer and advanced adenomas were found, respectively, in 11 and 48 of G-FOBTs and in 24 and 121 of I-FOBTs. Differences in positive predictive value for cancer and advanced adenomas and cancer were, respectively, 2.1% (P = .4) and -3.6% (P = .5). Differences in specificities favor G-FOBT and were, respectively, 2.3% (P < .01) and -1.3% (P < .01). Differences in intention-to-screen detection rates favor I-FOBT and were, respectively, 0.1% (P < .05) and 0.9% (P < .01). CONCLUSIONS The number-to-scope to find 1 cancer was comparable between the tests. However, participation and detection rates for advanced adenomas and cancer were significantly higher for I-FOBT. G-FOBT significantly underestimates the prevalence of advanced adenomas and cancer in the screening population compared with I-FOBT.


Gut | 2014

Healthcare costs of inflammatory bowel disease have shifted from hospitalisation and surgery towards anti-TNFα therapy: results from the COIN study.

Mirthe E. van der Valk; Marie-Josée J. Mangen; Max Leenders; Gerard Dijkstra; Ad A. van Bodegraven; Herma H. Fidder; Dirk J. de Jong; Marieke Pierik; C. Janneke van der Woude; Mariëlle Romberg-Camps; Cees H. Clemens; Jeroen M. Jansen; Nofel Mahmmod; Paul C. van de Meeberg; Andrea E. van der Meulen-de Jong; Cyriel Y. Ponsioen; Clemens J. M. Bolwerk; J. Reinoud Vermeijden; Peter D. Siersema; Martijn G. van Oijen; Bas Oldenburg

Objective The introduction of anti tumour necrosis factor-α (anti-TNFα) therapy might impact healthcare expenditures, but there are limited data regarding the costs of inflammatory bowel diseases (IBD) following the introduction of these drugs. We aimed to assess the healthcare costs and productivity losses in a large cohort of IBD patients. Design Crohns disease (CD) and ulcerative colitis (UC) patients from seven university hospitals and seven general hospitals were invited to fill-out a web-based questionnaire. Cost items were derived from a 3 month follow-up questionnaire and categorised in outpatient clinic, diagnostics, medication, surgery and hospitalisation. Productivity losses included sick leave of paid and unpaid work. Costs were expressed as mean 3-month costs per patients with a 95% CI obtained using non-parametric bootstrapping. Results A total of 1315 CD patients and 937 UC patients were included. Healthcare costs were almost three times higher in CD as compared with UC, €1625 (95% CI €1476 to €1775) versus €595 (95% CI €505 to €685), respectively (p<0.01). Anti-TNFα use was the main costs driver, accounting for 64% and 31% of the total cost in CD and UC. Hospitalisation and surgery together accounted for 19% and <1% of the healthcare costs in CD and 23% and 1% in UC, respectively. Productivity losses accounted for 16% and 39% of the total costs in CD and UC. Conclusions We showed that healthcare costs are mainly driven by medication costs, most importantly by anti-TNFα therapy. Hospitalisation and surgery accounted only for a minor part of the healthcare costs.


Gastroenterology | 2009

Lanreotide Reduces the Volume of Polycystic Liver: A Randomized, Double-Blind, Placebo-Controlled Trial

Loes van Keimpema; Frederik Nevens; Ragna Vanslembrouck; Martijn G. van Oijen; Aswin L. Hoffmann; Helena M. Dekker; Robert A. de Man; Joost P. H. Drenth

BACKGROUND & AIMS Therapy for polycystic liver is invasive, expensive, and has disappointing long-term results. Treatment with somatostatin analogues slowed kidney growth in patients with polycystic kidney disease (PKD) and reduced liver and kidney volume in a PKD rodent model. We evaluated the effects of lanreotide, a somatostatin analogue, in patients with polycystic liver because of autosomal-dominant (AD) PKD or autosomal-dominant polycystic liver disease (PCLD). METHODS We performed a randomized, double-blind, placebo-controlled trial in 2 tertiary referral centers. Patients with polycystic liver (n = 54) were randomly assigned to groups given lanreotide (120 mg) or placebo, administered every 28 days for 24 weeks. The primary end point was the difference in total liver volume, measured by computerized tomography at weeks 0 and 24. Analyses were performed on an intention-to-treat basis. RESULTS Baseline characteristics were comparable for both groups, except that more patients with ADPKD were assigned to the placebo group (P = .03). The mean liver volume decreased 2.9%, from 4606 mL (95% confidence interval (CI): 547-8665) to 4471 mL (95% CI: 542-8401 mL), in patients given lanreotide. In the placebo group, the mean liver volume increased 1.6%, from 4689 mL (95% CI: 613-8765 mL) to 4895 mL (95% CI: 739-9053 mL) (P < .01). Post hoc stratification for patients with ADPKD or PCLD revealed similar changes in liver volume, with statistically significant differences in patients given lanreotide (P < .01 for both diseases). CONCLUSIONS In patients with polycystic liver, 6 months of treatment with lanreotide reduces liver volume.


Inflammatory Bowel Diseases | 2013

Declining risk of colorectal cancer in inflammatory bowel disease: an updated meta-analysis of population-based cohort studies.

Maurice W. Lutgens; Martijn G. van Oijen; Geert J. M. G. van der Heijden; Frank P. Vleggaar; Peter D. Siersema; Bas Oldenburg

Background:Recently reported risks of colorectal cancer (CRC) in inflammatory bowel disease (IBD) have been lower than those reported before 2000. The aim of this meta-analysis was to update the CRC risk of ulcerative and Crohn’s colitis, investigate time trends, and identify high-risk modifiers. Methods:The MEDLINE search engine was used to identify all published cohort studies on CRC risk in IBD. Publications were critically appraised for study population, Crohn’s disease localization, censoring for colectomy, and patient inclusion methods. The following data were extracted: total and stratified person-years at risk, number of observed CRC, number of expected CRC in background population, time period of inclusion, and geographical location. Pooled standardized incidence ratios and cumulative risks for 10-year disease intervals were calculated. Results were corrected for colectomy and isolated small bowel Crohn’s disease. Results:The pooled standardized incidence ratio of CRC in all patients with IBD in population-based studies was 1.7 (95% confidence interval [CI], 1.2–2.2 ). High-risk groups were patients with extensive colitis and an IBD diagnosis before age 30 with standardized incidence ratios of 6.4 (95% confidence interval, 2.4–17.5) and 7.2 (95% confidence interval, 2.9–17.8), respectively. Cumulative risks of CRC were 1%, 2%, and 5% after 10, 20, and >20 years of disease duration, respectively. Conclusions:The risk of CRC is increased in patients with IBD but not as high as previously reported and not in all patients. This decline could be the result of aged cohorts. The risk of CRC is significantly higher in patients with longer disease duration, extensive disease, and IBD diagnosis at young age.


Clinical Gastroenterology and Hepatology | 2013

Long-term Risk of Acute Diverticulitis Among Patients With Incidental Diverticulosis Found During Colonoscopy

Kamyar Shahedi; Garth Fuller; Roger Bolus; Erica R. Cohen; Michelle Vu; Rena Shah; Nikhil Agarwal; Marc Kaneshiro; Mary A. Atia; Victoria Sheen; Nicole Kurzbard; Martijn G. van Oijen; Linnette Yen; Paul Hodgkins; M. Haim Erder; Brennan M. Spiegel

BACKGROUND & AIMS Colonic diverticulosis is the most common finding during routine colonoscopy, and patients often question the significance of these lesions. Guidelines state that these patients have a 10% to 25% lifetime risk of developing acute diverticulitis. However, this value was determined based on limited data, collected before population-based colonoscopy, so the true number of cases of diverticulosis was not known. We measured the long-term risk of acute diverticulitis among patients with confirmed diverticulosis discovered incidentally on colonoscopy. METHODS We performed a retrospective study using administrative and clinical data from the Veterans Affairs Greater Los Angeles Healthcare System, collecting data on patients who underwent colonoscopies from January 1996 through January 2011. We identified patients diagnosed with diverticulosis, determined incidence rates per 1000 patient-years, and analyzed a subgroup of patients with rigorously defined events confirmed by imaging or surgery. We used a Cox proportional hazards model to identify factors associated with the development of diverticulitis. RESULTS We identified 2222 patients with baseline diverticulosis. Over an 11-year follow-up period, 95 patients developed diverticulitis (4.3%; 6 per 1000 patient-years); of these, 23 met the rigorous definition of diverticulitis (1%; 1.5 per 1000 patient-years). The median time-to-event was 7.1 years. Each additional decade of age at time of diagnosis reduced the risk for diverticulitis by 24% (hazard ratio, 0.76; 95% confidence interval, 0.6-0.9). CONCLUSIONS Based on a study of the Veterans Affairs Greater Los Angeles Healthcare System, only about 4% of patients with diverticulosis develop acute diverticulitis, contradicting the common belief that diverticulosis has a high rate of progression. We also found that younger patients have a higher risk of diverticulitis, with risk increasing per year of life. These results can help inform patients with diverticulosis about their risk of developing acute diverticulitis.


Gut | 2011

Thiopurines prevent advanced colorectal neoplasia in patients with inflammatory bowel disease

Fiona van Schaik; Martijn G. van Oijen; Hugo M. Smeets; Geert J. M. G. van der Heijden; Peter D. Siersema; Bas Oldenburg

Background and aims Previous studies have suggested a chemopreventive effect of 5-aminosalicylic acid (5-ASA) therapy in patients with inflammatory bowel disease (IBD). This effect has not been reported in IBD patients using thiopurines. We investigated the association between thiopurine or 5-ASA use and the risk of advanced neoplasia (AN), including high-grade dysplasia and colorectal cancer, in a large cohort of patients with IBD in the Netherlands. Methods PALGA, the nationwide network and registry of histo- and cytopathology in The Netherlands was linked to an anonymised computerised database of a Dutch health insurance company to identify patients with IBD with or without AN. Pharmaceutical data, including type and duration of medication use, were collected between January 2001 and December 2009. Cox proportional hazard regression analysis was used to calculate risk of AN in patients with and without thiopurine or 5-ASA use. Results A total of 2578 patients with IBD were included. Of these, 973 patients (38%) used 5-ASA, 314 (12%) thiopurines, 456 (18%) both 5-ASA and thiopurines and 835 (32%) none of these drugs. Twenty-eight patients (1%) developed AN during 16 289 person-years of follow-up. Of these, 11 patients (39%) had used 5-ASA, two (7%) thiopurines and one (4%) both drugs. Thiopurine use was associated with a significantly decreased risk of developing AN (adjusted HR 0.10, 95% CI 0.01 to 0.75). 5-ASA therapy also had a protective effect on developing AN, but this was not statistically significant (adjusted HR 0.56, 95% CI 0.22 to 1.40). Conclusion Thiopurine use protects IBD patients against the development of AN. The effect of 5-ASA appeared to be less pronounced.


Liver International | 2011

Patients with isolated polycystic liver disease referred to liver centres: clinical characterization of 137 cases

Loes van Keimpema; Daan B. de Koning; Bart van Hoek; Aad P. van den Berg; Martijn G. van Oijen; Robert A. de Man; Frederik Nevens; Joost P. H. Drenth

Background and aim: Isolated polycystic liver disease (PCLD) is characterized by the presence of multiple cysts in the liver in the absence of polycystic kidneys. The clinical profile of PCLD is poorly defined and we set up a study for the clinical characteristics of PCLD.


Journal of Hepatology | 2010

Treatment options for autoimmune hepatitis: A systematic review of randomized controlled trials

M.H. Lamers; Martijn G. van Oijen; Martine Pronk; Joost P. H. Drenth

BACKGROUND & AIMS Predniso(lo)ne with or without azathioprine is considered the mainstay in the treatment of autoimmune hepatitis (AIH), but many therapeutic options are available. The primary objective of this review was to explore the published literature on the optimal induction and subsequent maintenance therapy for AIH. METHODS We performed a systematic search on electronic databases MEDLINE (1950-07.2009), Web of Science, Cochrane, and the website www.clinicaltrials.gov. Randomized controlled trials (RCTs) on apparent beneficial treatment regimens as induction or maintenance treatment in AIH were included. Pediatric studies were excluded. We calculated relative risks (RR) for comparison of treatment options on the primary outcome measure, which was defined as clinical, biochemical and histological remission. RESULTS Eleven RCTs were included, of which 7 studies evaluated the induction therapy in AIH patients: 3 treatment naive (n=253), 2 relapse (n=53), 2 combination of naive and relapse (n=110). The remaining 4 studies (n=162) assessed maintenance therapy. All but one maintenance study (thymostimulin versus no therapy) studied predniso(lo)ne (PRED), azathioprine (AZA) or combination PRED+AZA. We found no differences in primary outcome between induction therapy with PRED and PRED+AZA in treatment naive patients (RR=0.98; 95% CI 0.65-1.47). AZA monotherapy as induction was considered as not viable because of a high mortality rate (30%). This was similar in AIH patients who relapsed: RR for PRED versus PRED+AZA for inducing remission was not different: 0.71 (95% CI 0.37-1.39). PRED+AZA maintained remission more often than PRED (RR=1.40; 95% CI 1.13-1.73). Also AZA maintained a higher remission rate than PRED (RR=1.35; 95% CI 1.07-1.70). Maintenance of remission was not different between PRED+AZA and AZA (RR=1.06; 95% CI 0.94-1.20). CONCLUSIONS Based on available RCTs, PRED monotherapy and PRED+AZA combination therapy are both viable induction therapies for AIH treatment naives and relapsers, while for maintenance therapy PRED+AZA and AZA therapy are superior to PRED monotherapy.


Scandinavian Journal of Gastroenterology | 2012

Rationale in diagnosis and screening of atrophic gastritis with stomach-specific plasma biomarkers

Lars Agréus; Ernst J. Kuipers; Peter Malfertheiner; Francesco Di Mario; Marcis Leja; Varocha Mahachai; Niv Yaron; Martijn G. van Oijen; Guillermo I. Perez Perez; Massimo Rugge; Jukka Ronkainen; Mikko Salaspuro; Pentti Sipponen; Kentaro Sugano; Joseph J.Y. Sung; Erasmus Mc

Abstract Background and aims. Atrophic gastritis (AG) results most often from Helicobacter pylori (H. pylori) infection. AG is the most important single risk condition for gastric cancer that often leads to an acid-free or hypochlorhydric stomach. In the present paper, we suggest a rationale for noninvasive screening of AG with stomach-specific biomarkers. Methods. The paper summarizes a set of data on application of the biomarkers and describes how the test results could be interpreted in practice. Results. In AG of the gastric corpus and fundus, the plasma levels of pepsinogen I and/or the pepsinogen I/pepsinogen II ratio are always low. The fasting level of gastrin-17 is high in AG limited to the corpus and fundus, but low or non-elevated if the AG occurs in both antrum and corpus. A low fasting level of G-17 is a sign of antral AG or indicates high intragastric acidity. Differentiation between antral AG and high intragastric acidity can be done by assaying the plasma G-17 before and after protein stimulation, or before and after administration of the proton pump inhibitors (PPI). Amidated G-17 will rise if the antral mucosa is normal in structure. H. pylori antibodies are a reliable indicator of helicobacter infection, even in patients with AG and hypochlorhydria. Conclusions. Stomach-specific biomarkers provide information about the stomach health and about the function of stomach mucosa and are a noninvasive tool for diagnosis and screening of AG and acid-free stomach.


International Journal of Cancer | 2009

False negative fecal occult blood tests due to delayed sample return in colorectal cancer screening

Leo G.M. van Rossum; Anne F. van Rijn; Martijn G. van Oijen; Paul Fockens; Robert J.F. Laheij; A.L.M. Verbeek; Jan B.M.J. Jansen; Evelien Dekker

Delayed return of immunochemical fecal occult blood test (iFOBT) samples to a laboratory might cause false negatives because of hemoglobin degradation. Quantitative iFOBTs became increasingly more accepted in colorectal cancer screening. Therefore, we studied the effects of delay between sampling and laboratory delivery on iFOBT performance. IFOBT positivity (≥50 ng/ml hemoglobin) in colorectal cancer screening participants without delay between sampling and laboratory delivery (<5 days), was compared with positivity in participants with ≥5 and ≥7 days delay. Additionally, positive tests were stored at room temperature and retested 5 times within 10–14 days. The sampling date was reported by 61% (n = 3,767) of the participants: in 19% delay was ≥5 days and in 5% ≥7 days. Compared with no‐delay, the adenoma detection rate was already significantly decreased after ≥5 days delay (OR 0.6; 95%CI 0.4–0.9). We retested iFOBT samples of 170 positives of which 139 (82%) had a colonoscopy: 45 (32%) had advanced adenomas (not colorectal cancer) and 8 (6%) had colorectal cancer. Mean daily fecal hemoglobin decrease was 29 ng/ml (S.D. 38 and median 11 ng/ml). In patients with advanced adenomas, hemoglobin in the sample was <50 ng/ml in 5 (11%) 2–3 days after the initial test and in 16 (36%) after 10–14 days. Seven days after the initial test, 2 (25%) colorectal cancer patients became false negative. Both had stage I colorectal cancer and initial values below 100 ng/ml, where the average for stage I is 532 ng/ml. Delay in sample return increased false negative immunochemical FOBTs. Mainly precursor lesions, but also colorectal cancer, will be missed due to delayed sample return.

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Peter D. Siersema

Radboud University Nijmegen

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Dirk J. de Jong

Radboud University Nijmegen

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Joost P. H. Drenth

Radboud University Nijmegen

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Brennan M. Spiegel

Cedars-Sinai Medical Center

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