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T van der Weijden

Publications and source records attributed to T van der Weijden.

14 recordsLinked to original sources
PubMed2003

Designing a quality improvement intervention: a systematic approach.

Most quality improvement or change management interventions are currently designed intuitively and their results are often disappointing. While improving the effectiveness of interventions requires systematic development, no specific methodology for composing intervention strategies and programmes is available. This paper describes the methodology of systematically designing quality of care improvement interventions, including problem analysis, intervention design and pretests. Several theories on quality improvement and change management are integrated and valuable materials from health promotion are added. One method of health promotion-intervention mapping-is introduced and applied. It describes the translation of knowledge about barriers to and facilitators of change into a concrete intervention programme. Systematic development of interventions, although time consuming, appears to be worthwhile. Decisions that have to be made during the design process of a quality improvement intervention are visualised, allowing them to serve as a starting point for a systematic evaluation of the intervention.

Decision Making, Organizational↗
PubMed2001

[Roaming through methodology. XXXII. False test results].

The number of requests for diagnostic tests is rising. This leads to a higher chance of false test results. The false-negative proportion of a test is the proportion of negative test results among the diseased subjects. The false-positive proportion is the proportion of positive test results among the healthy subjects. The calculation of the false-positive proportion is often incorrect. For example, instead of 1 minus the specificity it is calculated as 1 minus the positive predictive value. This can lead to incorrect decision-making with respect to the application of the test. Physicians must apply diagnostic tests in such a way that the risk of false test results is minimal. The patient should be aware that a perfectly conclusive diagnostic test is rare in medical practice, and should more often be informed of the implications of false-positive and false-negative test results.

Data Interpretation, Statistical↗
PubMed2001

Systematic reviews of diagnostic research. Considerations about assessment and incorporation of methodological quality.

The aim of this paper is to provide a theoretical background for performing and reading systematic reviews of diagnostic studies. We first discuss items for assessment of methodological quality in diagnostic studies and then present methods on how to incorporate these quality measures in systematic reviews. The items of internal validity determine whether the presented results of the individual studies are unbiased and can be trusted. Items of external validity determine to what extent the results are applicable outside the population in which the study was performed. The issues concern the adequacy of the study population, the performance and interpretation of the diagnostic tests and the presentation of the results. Several methods exist for incorporation of issues of methodological quality into systematic reviews, such as subgroup analyses, meta-regression analysis, and methodological scores. Publications of diagnostic studies should provide sufficient information to enable assessment of the methodological quality. Furthermore, publication of results of subgroup analyses should be promoted. Methodological criteria lists might help to improve the quality of systematic reviews of diagnostic research. With the items of methodological quality in mind the general practitioner might be better equipped to critically read and interpret diagnostic reviews.

Epidemiologic Studies↗
PubMed2000

[Limited changes in prescription of third-generation oral contraceptives after reports on elevated thrombosis risk and subsequent professional guidelines].

OBJECTIVE: To compare the prescription behaviour of general practitioners (GP) and gynaecologists regarding 2nd and 3rd generation oral contraceptives (OC) in the period before and after the warning of increased thrombosis risk of 3rd generation pills. DESIGN: Retrospective, descriptive. METHOD: With the aid of data on OC prescriptions collected by the Institute for Medical Statistics, the numbers of prescriptions from Dutch GPs and gynaecologists in the year before the warning by the British Committee on Safety of Medicines that 3rd-generation OC increased the risk of thrombosis, were compared with the numbers in the year after publication of the guideline of the Dutch General Practitioners Society (NHG), which stated a preference for the 2nd-generation OC, and of the guideline of the Dutch Society for Gynaecology and Obstetrics, which stated no preference. RESULTS: In neither the GP nor the gynaecologist groups did the proportion of 3rd-generation pills in the OC prescriptions decrease significantly. However, in the GP group the proportion of new 3rd generation OC prescriptions decreased significantly from 56 to 40%. However, after a few trimesters it rose again. CONCLUSION: The changes in prescription behaviour of the GP group were in accordance with the NHG guidelines. However, the proportion of the 3rd-generation OC prescriptions remained relatively large and the effect was of short duration. The only conclusion that could be drawn regarding the gynaecologists, was that the proportion of 3rd-generation OC prescriptions did not change significantly.

Contraceptives, Oral↗
PubMed1999

Feasibility of a national cholesterol guideline in daily practice. A randomized controlled trial in 20 general practices.

OBJECTIVE: To evaluate the feasibility and implementation needs of a cholesterol guideline by assessing the effectiveness of simple dissemination as well as extensive implementation of this guideline on actual performance of general practitioners (GPs). DESIGN: Randomized controlled trial. SETTING AND SUBJECTS: Thirty-two Dutch GPs in 20 general practices, 3950 patient records. INTERVENTIONS: Guideline dissemination to all 32 GPs, and a 5-month programme for improvement in the intervention group. This programme was developed after barriers to working according to the guideline had been investigated, and consisted of group education, desktop supportive materials, feedback on performance, and face-to-face instruction on location. MAIN OUTCOME MEASURES: The outcome parameters were defined as quality of selective case finding and quality of diagnostic procedures, and were measured by chart audit. RESULTS: The quality of selective case finding, especially the targeting of cholesterol testing to those with positive cardiovascular risk profiles, did not improve following intervention. Performance of the procedure necessary to diagnose hypercholesterolaemia even deteriorated. The quantity of cholesterol testing increased in both groups, but this was probably explained by the increased availability of desktop cholesterol analysers. CONCLUSIONS: Neither simple dissemination nor an intensive programme for improvement had measurable impact on actual performance on working according to the cholesterol guideline. Both the validity and the opinion about feasibility of the guideline in daily practice deserve more attention during guideline development.

Family Practice↗
PubMed1999

Interventions to improve the delivery of preventive services in primary care.

OBJECTIVES: This review was conducted to determine the effectiveness of different interventions to improve the delivery of preventive services in primary care. METHODS: MEDLINE searches and manual searches of 21 scientific journals and the Cochrane Effective Professional and Organization of Care of trials were used to identify relevant studies. Randomized controlled trials and controlled before-and-after studies were included if they focused on interventions designed to improve preventive activities by primary care clinicians. Two researchers independently assessed the quality of the studies and extracted data for use in constructing descriptive overviews. RESULTS: The 58 studies included comprised 86 comparisons between intervention and control groups. Postintervention differences between intervention and control groups varied widely within and across categories of interventions. Most interventions were found to be effective in some studies, but not effective in other studies. CONCLUSIONS: Effective interventions to increase preventive activities in primary care are available. Detailed studies are needed to identify factors that influence the effectiveness of different interventions.

Delivery of Health Care↗
PubMed1998

Economic evaluation of cholesterol-related interventions in general practice. An appraisal of the evidence.

STUDY OBJECTIVE: To investigate and evaluate published data on cost effectiveness of cholesterol lowering interventions, and how this information could be interpreted in a rational approach of cholesterol management in general practice. DESIGN: A systematic review of the literature. SETTING: No restriction on setting. MATERIALS: Papers reporting on the cost effectiveness or cost utility of prevention of (recurrent) coronary heart disease by reduction of hypercholesterolaemia in adults. MAIN RESULTS: Thirty nine studies, most cost effectiveness analyses, were included. In 24 studies drug interventions only were analysed. Costs of screening to target cholesterol lowering interventions to persons with hypercholesterolaemia were considered in nine studies. Adjustments of the efficacy of the intervention for community effectiveness were described in seven studies. In four studies life years gained were adjusted for quality of life. Despite large variation in the outcomes, there is a constant tendency towards a less favourable cost effectiveness ratio for intervening in persons without coronary heart disease compared with persons with coronary heart disease and for women compared with men. CONCLUSIONS: There is lack of data on cost effectiveness of cholesterol lowering interventions in the general practice setting. The cost effectiveness of cholesterol lowering in general practice deteriorates when all relevant costs are taken into account and when efficacy is corrected for community effectiveness. Cholesterol lowering intervention is more cost effective in men compared with women and in patients with coronary heart disease compared with persons without coronary heart disease. Considerations from cost effectiveness analyses should be incorporated into the development and implementation of national cholesterol guidelines for general practitioners. Standardisation of cost effectiveness studies is important for future economic evaluations.

Coronary Disease↗
PubMed1998

Implementing guidelines and innovations in general practice: which interventions are effective?

BACKGROUND: It is crucial that research findings are implemented in general practice if high-quality care is to be achieved. Multifaceted interventions are usually assumed to be more effective than single interventions, but this hypothesis has yet to be tested for general practice care. This review evaluates the effectiveness of interventions in influencing the implementation of guidelines and adoption of innovations in general practice. A systematic literature study was carried out using MEDLINE searches for the period from January 1980 until June 1994, and 21 medical journals were searched manually. Randomized controlled trials and controlled before and after studies (with pre- and post-intervention measurements in all groups) were selected for the analysis. Clinical area, interventions used, methodological characteristics and effects on clinical behaviour were noted independently by two researchers using a standardized scoring form. Of 143 studies found, 61 were selected for the analysis, covering 86 intervention groups that could be compared with a control group without the intervention. Information transfer alone was effective in two out of 18 groups, whereas combinations of information transfer and learning through social influence or management support were effective in four out of eight and three out of seven groups respectively. Information linked to performance was effective in 10 out of 15 groups, but the combination of information transfer and information linked to performance was effective in only three out of 20 groups. Some, but not all, multifaceted interventions are effective in inducing change in general practice. Social influence and management support can improve the effectiveness of information transfer, but information linked to performance does not necessarily do so. The variation in the effectiveness of interventions needs further analysis.

Family Practice↗
PubMed1997

Identifying relevant diagnostic studies in MEDLINE. The diagnostic value of the erythrocyte sedimentation rate (ESR) and dipstick as an example.

OBJECTIVE: We aimed to examine sensitivity and positive predictive value of MEDLINE searching for diagnostic studies, relevant for the primary health care setting. METHOD: Results of MEDLINE searches were compared with a reference standard collection of studies on two subjects, the diagnostic value of ESR in discriminating between 'pathology' and 'no pathology', and the dipstick method in diagnosing urinary tract infections. The main outcome measures were sensitivity (proportion of the total number of reference standard diagnostic studies that could be identified by the search) and positive predictive value (proportion of the total number of publications retrieved by MEDLINE that were incorporated in the reference standard). RESULTS: The combined MeSH and freetext search was more sensitive than MeSH term searching only, for both the ESR and the dipstick search. With this combined search sensitivities of 0.91 and 0.98 and predictive values of 0.10 and 0.68 were found for ESR and dipstick respectively. By restricting the search with keywords describing the primary health care setting the predictive values increased to 0.72 and 1.00 but sensitivity dropped to 0.10 and 0.07 (ESR and dipstick respectively). CONCLUSION: Combining freetext and MeSH term searching, without restriction to the primary health care setting, is a valuable strategy in systematically searching for available evidence on the value of a diagnostic test in the scope of a specific disease. The predictive value seems to depend on the breadth of the disease area. MEDLINE should provide a term such as 'diagnostic evaluation study' to be used in the limit field Publication Type to specify diagnostic studies.

Blood Sedimentation↗
PubMed1996

Comparison of appropriateness of cholesterol testing in general practice with the recommendations of national guidelines: an audit of patient records in 20 general practices.

OBJECTIVE: To compare the profiles of those patients selected by general practitioners for measurement of serum cholesterol with the recommended profiles for opportunistic cholesterol testing described in the national practice guidelines published by the Dutch College of General Practitioners. DESIGN: Retrospective audit of general practitioners' records. MATERIALS: Practice records of 3577 adult patients systematically sampled from 20 general practices. MAIN MEASURES: With criteria set by the national guidelines, the proportion of patients per practice (a) for whom cholesterol testing would be considered justified, and (b) for whom cholesterol testing would be considered unjustified, and the proportion of patients within each of these groups who had had a cholesterol measurement recorded. RESULTS: Cholesterol tests were performed on 415 (11.7%) of the 3577 patients. National guidelines on the management of hypercholesterolaemia state that a positive cardiovascular risk profile is an indication for cholesterol measurement. Just under one fifth (668) of the patients in this study were recorded as having a positive cardiovascular risk profile, but only 31% of these had had their cholesterol measured. Of the patients without recorded evidence of a positive cardiovascular risk profile cholesterol had been measured in 8%. Restricting the analyses to the age group 18-65 (n = 3060) of whom 12.5% had a positive risk profile, did not improve the results. In practices with a computerised information system 37% of patients with recorded evidence of a positive cardiovascular risk profile had had their cholesterol measured. CONCLUSIONS: Cholesterol testing was not targeted as selectively as recommended by the national guidelines. The major problem was failure to test those likely to benefit. Improving the targeting of cholesterol measurements would undoubtedly increase the workload of general practitioners. If the national guidelines are to have an effect on health promotion the first step must be to increase the proportion of patients with positive cardiovascular risk profiles who get their cholesterol tested. A major factor in successfully selecting cases seems to be that practices are equipped with a computerised medical information system.

Adolescent↗
PubMed1994

Cholesterol management in Dutch general practice. A comparison with national guidelines. Dutch College of General Practitioners.

OBJECTIVE: To examine cholesterol diagnosis and treatment by Dutch general practitioners (GPs) in the period before publication of national guidelines, in order to develop implementation strategies based on discrepancies found between daily practice and the guidelines. DESIGN: Data of the 'Dutch National Survey of General Practice', in which GPs were involved in extensive consultation registration, were used. Patients were included for analysis if serum cholesterol, or the ICPC-code lipid metabolism disorder, or cholesterol-lowering treatment was registered. SETTING: General practice. PARTICIPANTS: 161 GPs, 177 practice-nurses. OUTCOME MEASURES: Reasons for consultation, diagnoses, therapy, inter-doctor variation. RESULTS: The main discrepancies between daily practice and the guidelines concerned indications for cholesterol measurement, repeated measurements to diagnose hypercholesterolaemia, and attention for diet advice. A remarkable inter-doctor variation in diagnosis, and less so in treatment, was also found. CONCLUSION: The inter-doctor variation justifies the publication of the standard guidelines. Implementation strategies should aim at indications for cholesterol testing, repeating measurements for diagnosis, and advice on diet.

Adolescent↗