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Dive into the research topics where Charles W Helsper is active.

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Featured researches published by Charles W Helsper.


Pharmacoepidemiology and Drug Safety | 2009

Trends and determinants of adequate gastroprotection in patients chronically using NSAIDs

Charles W Helsper; Hugo M. Smeets; Mattijs E. Numans; Mirjam J. Knol; Arno W. Hoes; Niek J. de Wit

To identify determinants and trends of gastroprotection in patients chronically using NSAIDs.


British Journal of General Practice | 2012

Follow-up of mild alanine aminotransferase elevation identifies hidden hepatitis C in primary care

Charles W Helsper; Gerrit A van Essen; B.D. Frijling; Niek J. de Wit

BACKGROUND Hepatitis C (HCV) and hepatitis B (HBV) virus infection can lead to serious complications if left untreated, but often remain undetected in primary care. Mild alanine aminotransferase (ALT) elevations (30-100 IU/l) are commonly found and could be associated with viral hepatitis; unfortunately, these findings frequently remain without follow-up. AIM To determine if and how mild ALT elevation can be used to identify hidden HCV and HBV infection in primary care. DESIGN AND SETTING Primary care patients referred for liver enzyme testing were selected by a large primary care Diagnostic Centre (Saltro). METHOD First, 750 anonymous samples were collected in three categories of ALT elevation (30-50 IU/l, 50-70 IU/l, and 70-100 IU/l) and tested for HCV and HBV. Second, the national prevalence of each ALT elevation was estimated by analysing all annual ALT tests performed at Saltro. RESULTS HCV prevalence was 1.6% and 1.2% in patients with an ALT of 50-70 IU/l and 70-100 IU/l respectively. In patients with an ALT of 30-50 IU/l, HCV prevalence was normal (≤0.1%). HBV prevalence was normal (≤0.4%) in all groups. The estimated number of ALT tests performed nationally each year in primary care was 1.1 million. An ALT of 30-50 IU/l was found in 21.1%, an ALT of 50-70 IU/l in 5.6%, and 2.6% had an ALT of 70-100 IU/l. CONCLUSION In primary care patients with an ALT level of 50-100 IU/l, HCV prevalence is tenfold the population prevalence, whereas HBV prevalence is not elevated. Therefore, diagnostic follow-up for HCV is indicated in these patients, even when other explanations for ALT elevation are present.


Epidemiology and Infection | 2012

Cost-effectiveness of targeted screening for hepatitis C in The Netherlands.

Charles W Helsper; B. A. Borkent-Raven; N.J. de Wit; G A van Essen; Marc J. M. Bonten; Andy I. M. Hoepelman; Mart P. Janssen; G.A. de Wit

On account of the serious complications of hepatitis C virus (HCV) infection and the improved treatment possibilities, the need to improve HCV awareness and case-finding is increasingly recognized. To optimize a future national campaign with this objective, three pilot campaigns were executed in three regions in The Netherlands. One campaign was aimed at the general population, a second (similar) campaign was extended with a support programme for primary care and a third campaign was specifically aimed at hard-drug users. Data from the pilot campaigns were used to build a mathematical model to estimate the incremental cost-effectiveness ratio of the different campaigns. The campaign aimed at the general public without support for primary care did not improve case-finding and was therefore not cost-effective. The similar campaign accompanied by additional support for primary care and the campaign aimed at hard-drug users emerged as cost-effective interventions for identification of HCV carriers.


Family Practice | 2010

A support programme for primary care leads to substantial improvements in the effectiveness of a public hepatitis C campaign

Charles W Helsper; Gerrit A van Essen; Marc J. M. Bonten; Niek J. de Wit

INTRODUCTION Because of its lack of clinical signs, the detection of hepatitis C virus (HCV) infection in the Netherlands remains suboptimal. Therefore, the Dutch Health Council proposed an HCV campaign aimed to inform the general public and motivate people at risk to seek medical advice. Because knowledge and awareness of HCV infection is low among primary care workers, the implementation of a support programme for primary care complementary to a HCV campaign seems appropriate. OBJECTIVE To evaluate the added value of a support programme for primary care complementary to a public HCV campaign. METHODS We performed a non-randomized controlled intervention study. In two similar regions, a public HCV campaign was organized. In the intervention region, an additional support for primary care was provided by means of brochures, short courses and informative visits. RESULTS In the intervention region, the proportional increase in anti-HCV tests was 3.02 (57-172 tests). In the control region, this increase was 1.36 (86-118 tests). In the intervention region, the increase in positive anti-HCV tests was 1.7% (95% confidence interval (CI): -0.2% to -3.7%). In the control region, this number decreased by 0.9% (95% CI: -4.1% to 2.3%). CONCLUSIONS The addition of primary care practice support leads to considerable improvements in medical consciousness regarding HCV infection in primary care. Even though the positive effect on case finding cannot be indisputably demonstrated due to low prevalence, our results indicate such a positive effect. Therefore, future campaigns aimed at hepatitis C should invariably implement additional support for primary care to improve diagnostic uptake and optimize case finding.


BMC Public Health | 2014

Outcomes of hepatitis C screening programs targeted at risk groups hidden in the general population: a systematic review

Freke R Zuure; Anouk T. Urbanus; Miranda W. Langendam; Charles W Helsper; Charlotte van den Berg; Udi Davidovich; Maria Prins

BackgroundEffective screening programs are urgently needed to provide undiagnosed hepatitis C virus (HCV)-infected individuals with therapy. This systematic review of characteristics and outcomes of screening programs for HCV focuses on strategies to identify HCV risk groups hidden in the general population.MethodsWe conducted a comprehensive search of MEDLINE and EMBASE databases for articles published between 1991–2010, including studies that screened the general population using either a newly developed (nonintegrated) screening program or one integrated in existing health care facilities. Look-back studies, prevalence studies, and programs targeting high-risk groups in care (e.g., current drug users) were excluded.ResultsAfter reviewing 7052 studies, we identified 67 screening programs: 24 nonintegrated; 41 programs integrated in a variety of health care facilities (e.g., general practitioner); and 2 programs with both integrated and nonintegrated strategies. Together, these programs identified approximately 25,700 HCV-infected individuals. In general, higher HCV prevalence was found in programs in countries with intermediate to high HCV prevalence, in psychiatric clinics, and in programs that used a prescreening selection based on HCV risk factors. Only 6 programs used a comparison group for evaluation purposes, and 1 program used theory about effective promotion for screening. Comparison of the programs and their effectiveness was hampered by lack of reported data on program characteristics, clinical follow-up, and type of diagnostic test.ConclusionsA prescreening selection based on risk factors can increase the efficiency of screening in low-prevalence populations, and we need programs with comparison groups to evaluate effectiveness. Also, program characteristics such as type of diagnostic test, screening uptake, and clinical outcomes should be reported systematically.


International Journal of Medical Informatics | 2017

Reusability of coded data in the primary care electronic medical record : A dynamic cohort study concerning cancer diagnoses

Annet Sollie; Rolf H. Sijmons; Charles W Helsper; Mattijs E. Numans

OBJECTIVES To assess quality and reusability of coded cancer diagnoses in routine primary care data. To identify factors that influence data quality and areas for improvement. METHODS A dynamic cohort study in a Dutch network database containing 250,000 anonymized electronic medical records (EMRs) from 52 general practices was performed. Coded data from 2000 to 2011 for the three most common cancer types (breast, colon and prostate cancer) was compared to the Netherlands Cancer Registry. MEASUREMENTS Data quality is expressed in Standard Incidence Ratios (SIRs): the ratio between the number of coded cases observed in the primary care network database and the expected number of cases based on the Netherlands Cancer Registry. Ratios were multiplied by 100% for readability. RESULTS The overall SIR was 91.5% (95%CI 88.5-94.5) and showed improvement over the years. SIRs differ between cancer types: from 71.5% for colon cancer in males to 103.9% for breast cancer. There are differences in data quality (SIRs 76.2% - 99.7%) depending on the EMR system used, with SIRs up to 232.9% for breast cancer. Frequently observed errors in routine healthcare data can be classified as: lack of integrity checks, inaccurate use and/or lack of codes, and lack of EMR system functionality. CONCLUSIONS Re-users of coded routine primary care Electronic Medical Record data should be aware that 30% of cancer cases can be missed. Up to 130% of cancer cases found in the EMR data can be false-positive. The type of EMR system and the type of cancer influence the quality of coded diagnosis registry. While data quality can be improved (e.g. through improving system design and by training EMR system users), re-use should only be taken care of by appropriately trained experts.


BMJ Open | 2016

Do GPs know their patients with cancer? Assessing the quality of cancer registration in Dutch primary care: a cross-sectional validation study.

Annet Sollie; Jessika Roskam; Rolf H. Sijmons; Mattijs E. Numans; Charles W Helsper

Objectives To assess the quality of cancer registry in primary care. Design and setting A cross-sectional validation study using linked data from primary care electronic health records (EHRs) and the Netherlands Cancer Registry (NCR). Population 290 000 patients, registered with 120 general practitioners (GPs), from 50 practice centres in the Utrecht area, the Netherlands, in January 2013. Intervention Linking the EHRs of all patients in the Julius General Practitioners’ Network database at an individual patient level to the full NCR (∼1.7 million tumours between 1989 and 2011), to determine the proportion of matching cancer diagnoses. Full-text EHR extraction and manual analysis for non-matching diagnoses. Main outcome measures Proportions of matching and non-matching breast, lung, colorectal and prostate cancer diagnoses between 2007 and 2011, stratified by age category, cancer type and EHR system. Differences in year of diagnosis between the EHR and the NCR. Reasons for non-matching diagnoses. Results In the Primary Care EHR, 60.6% of cancer cases were registered and coded in accordance with the NCR. Of the EHR diagnoses, 48.9% were potentially false positive (not registered in the NCR). Results differed between EHR systems but not between age categories or cancer types. The year of diagnosis corresponded in 80.6% of matching coded diagnoses. Adding full-text EHR analysis improved results substantially. A national disease registry (the NCR) proved incomplete. Conclusions Even though GPs do know their patients with cancer, only 60.6% are coded in concordance with the NCR. Reusers of coded EHR data should be aware that 40% of cases can be missed, and almost half can be false positive. The type of EHR system influences registration quality. If full-text manual EHR analysis is used, only 10% of cases will be missed and 20% of cases found will be wrong. EHR data should only be reused with care.


Huisarts En Wetenschap | 2018

Zijn de gegevens uit uw HIS een goudmijn

Annet Sollie; Mattijs E. Numans; Charles W Helsper

SamenvattingStel, er komt een patiënt op uw spreekuur met een klacht die op een ernstige aandoening kan wijzen, zoals longkanker bij een chronisch hoestende patiënt. U maakt in uw HIS een episode aan met een ICPC-code voor longkanker. Gelukkig wijst nader onderzoek uit dat er niets aan de hand is. U vergeet echter de ICPC-code van de ernstige aandoening aan te passen. Voor de korte termijn heeft uw codeerfout geen gevolgen, maar wanneer bijvoorbeeld de huisartsenpost de door u in het HIS opgeslagen gegevens gebruikt, kan er veel misgaan. Hoe goed is de kwaliteit van (gecodeerde) gegevens in een doorsnee huisartsenpraktijk eigenlijk? Hoe kunnen we de kwaliteit ervan verbeteren en het hergebruik of delen van gegevens optimaliseren?


British Journal of General Practice | 2018

Identifying patients with a history of ovarian cancer for referral for genetic counselling: non-randomised comparison of two case-finding strategies in primary care

Charles W Helsper; Liesbeth van Vliet; M.E. Velthuizen; Niek J. de Wit; Roy Ph Beijaert; Els S. F. Butter; Marleen Pl van Gent-Wagemakers; Els Witteveen; Ronald P. Zweemer; Sandra van Dulmen; Margreet G. E. M. Ausems

Background Recent guidelines recommend genetic counselling and DNA testing (GCT) for patients with ovarian cancer and survivors of ovarian cancer. Finding survivors of ovarian cancer is challenging. Detecting and referring them for GCT via primary care, to allow proper screening recommendations for patients and their family, may be a solution. Aim To compare the effectiveness and acceptance of two pilot strategies directed at case finding women with a history of ovarian cancer for referral for GCT by their GP. Design and setting Non-randomised comparison of the pilot implementation of two case-finding strategies for women with a history of ovarian cancer in Dutch primary care from May 2016 to April 2017. Method Strategy A (unsupported) asked GPs to identify and refer eligible patients with a history of ovarian cancer. Strategy B (ICT-supported) provided GPs with information and communication technology (ICT) support to identify patients with a history of ovarian cancer electronically. The effectiveness of each strategy was assessed as the proportion of patients who were approached, referred for GCT, and seen by the clinical geneticist. Acceptance of each strategy was assessed by the intervention uptake of GP practices and GP and patient questionnaires. Results Nineteen out of 30 (63%) patients identified with a history of ovarian cancer were deemed eligible for referral for strategy A, and 39 out of 94 (41%) for strategy B. For each strategy, eight patients were referred and five (63%) were seen for GCT. The intervention uptake by GP practices was 31% (11 out of 36) for strategy A and 46% (21 out of 46) for strategy B. GPs considered ‘relevance’ and ‘workability’ as facilitators across both strategies whereas, for strategy B, technical barriers hindered implementation. Conclusion The effectiveness and acceptance of both strategies for case finding of survivors of ovarian cancer in primary care for GCT is promising, but larger studies are required before wide-scale implementation is warranted.


BMC Health Services Research | 2018

Routine primary care data for scientific research, quality of care programs and educational purposes: the Julius General Practitioners’ Network (JGPN)

Hugo M. Smeets; Marlous Kortekaas; Frans H. Rutten; Michiel L. Bots; Willem van der Kraan; Gerard Daggelders; Hanneke Smits-Pelser; Charles W Helsper; Arno W. Hoes; Niek J. de Wit

BackgroundGeneral Practitioners (GPs) in the Netherlands routinely register all patient contacts electronically. These records include longitudinally gathered clinical information of the patient contacts in coded data and free text.MethodsDiagnoses are coded according to the International Coding of Primary Care (ICPC). Drug prescriptions are labelled with the Anatomical Therapeutic Chemical Classification (ATC), and letters of hospital specialists and paramedic health care professionals are linked or directly incorporated in the electronic medical files. A network of a large group of GPs collecting routine care data on an ongoing basis can be used for answering various research questions.ResultsThe Julius General Practitioners’ Network (JGPN) database consists of routine care data from over ten years of a dynamic cohort of around 370,000 individuals registered with the participating GPs from the city of Utrecht and its vicinity. Health care data are extracted anonymously every quartile of a year and these data are used by researchers.ConclusionWe describe the content and usability of our JGPN database, and how a wide variety of research questions could be answered, as illustrated with examples of published articles.

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Mattijs E. Numans

Leiden University Medical Center

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Annet Sollie

VU University Amsterdam

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