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G J Bonsel

Publications and source records attributed to G J Bonsel.

At least 37 records · Page 2Linked to original sources
PubMed2002

Cost-effectiveness of a family and DNA based screening programme on familial hypercholesterolaemia in The Netherlands.

AIMS: To estimate the cost-effectiveness of the current screening programme on Familial Hypercholesterolaemia (FH) in relatives of diagnosed FH-patients in The Netherlands. METHODS AND RESULTS: Data from 2229 screened FH-relatives, including age, sex, risk factor status and screening outcome, were combined with the Framingham risk function and national disease-specific cost data to arrive at a model-based comparison of survival and costs, with and without the screening programme. Cost-effectiveness ratios were computed for various treatment strategies, with no screening as reference. Costs per life year gained varied between 25.5- and 32-thousand Euros, depending upon the precise treatment strategy after a positive screen. The costs for screening (tracing the FH-positive individuals) were much lower than the follow-up costs (treatment), of which 80% were costs for statins. Consequently, the costs per life year gained of alternative screening programmes are about the same. CONCLUSION: The cost-effectiveness ratio of FH screening is within the range requiring explicit political consideration in The Netherlands. As the costs of statin treatment are the single most important determinant of costs, policy decisions reduce to decisions on the acceptability of statin treatment for this risk group. Pending major changes in statin price, clear guidelines should be developed on how screen positive individuals should be treated, since not all of them have an elevated cholesterol level.

Adolescent↗
PubMed2001

Maternal health, antenatal and at 8 weeks after delivery, in home versus in-hospital fetal monitoring in high-risk pregnancies.

OBJECTIVE: To assess maternal health outcome, comparing high-risk pregnant women to either domiciliary monitoring or in-hospital monitoring, and a low risk pregnant group. DESIGN: Paper and pencil questionnaire, distributed antenatal and 8 weeks after the delivery. SETTING: A university hospital. SUBJECTS: Three groups: 130 high-risk pregnant women, who entered a randomized clinical trial and were allocated to either home (n=69) or in-hospital monitoring (n=61), and a reference cohort of low risk pregnant women (n=55). MAIN OUTCOME MEASURES: Antenatal physical and mental health (RAND36) and social experiences; mode of delivery; complications postpartum; physical health, mental health, and social experiences at 8 weeks postpartum. RESULTS: In all groups, antenatal physical health was considerably lower compared to the physical health of US women aged 18--44 years. Antenatal mental health was lower in high-risk women than in low-risk women (P<0.05). Antenatal maternal health, the mode of delivery, and maternal complications postpartum did not differ significantly between in-hospital and domiciliary monitored women. Eight weeks after delivery, physical health improved considerably in all groups; mental health was significantly lower in high-risks as compared to low-risk women (P<0.01). The allocated monitoring strategy showed a significant effect on mental health at 8 weeks after delivery; the mental health score being lower in the domiciliary monitored group (P<0.05). CONCLUSIONS: At 8 weeks after the delivery, physical health improves substantially in all groups. Mental health is higher in low-risks than in high-risks. Within the high-risk group domiciliary and in-hospital monitored women have the same physical maternal outcome at 8 weeks after delivery. However, mental maternal health in in-hospital monitored women at 8 weeks was probably biased by a medicalization effect.

Adolescent↗
PubMed2001

Vaginal birth after caesarean section in a population with a low overall caesarean section rate.

OBJECTIVE: To determine the clinical outcome of vaginal birth after caesarean section (VBAC) in a Dutch population with a low overall caesarean section (CS) rate of 6.5%. STUDY DESIGN: Prospective population based cohort study of 252 patients with a previous caesarean section (CS). Outcome parameters were trial of labour (TOL), success rate and VBAC rate. RESULTS: The TOL rate in the study cohort was 73%, success rate 77%, VBAC rate 56%. The reason for the previous CS influenced success rate. Complications, morbidity and mortality were not different between elective, emergency CS and TOL group, except for a higher incidence of haemorrhage more than 500 ml in the elective CS compared to the TOL group (29% versus 17%, relative risk (RR) 1.74 (1.15--2.34)). CONCLUSIONS: In this Dutch study the success rate is comparable to rate in US study reports. Increase of the VBAC rate can mainly be achieved by increasing the number of women attempting TOL.

Breech Presentation↗
PubMed2001

Measuring health status using the Health Utilities Index: agreement between raters and between modalities of administration.

The aim of this study was to evaluate interrater and intermodality agreement in assessing health status using the Health Utilities Index. A random sample from a Dutch cohort of 14-year-old Very Low Birth Weight children and their parents were invited to participate in a face-to-face (n = 150) or telephone (n = 150) interview. All 300 participants were also sent a questionnaire by mail. Response rate was 68%. Interrater and intermodality agreement were high for the physical HUI3 attributes and poor for the psychological attributes. Children and parents reported more dysfunction in the psychological attributes when interviewed than when completing the mailed questionnaire. High agreement on the physical attributes may have resulted from the fact that hardly any dysfunction was reported in these attributes, and poor agreement in the psychological attributes may have been a result of the fact that in these attributes much more dysfunction was reported. In measuring children's health status using the HUI3, the results and their interpretation vary with the source of information and the modality of administration. For maximum comparability between studies, written self-report questionnaires seem the preferred option.

Adolescent↗
PubMed2001

Randomized controlled trial of total intravenous anesthesia with propofol versus inhalation anesthesia with isoflurane-nitrous oxide: postoperative nausea with vomiting and economic analysis.

BACKGROUND: To assess the incidence of postoperative nausea and vomiting after total intravenous anesthesia (TIVA) with propofol versus inhalational anesthesia with isoflurane-nitrous oxide, the authors performed a randomized trial in 2,010 unselected surgical patients in a Dutch academic institution. An economic evaluation was also performed. METHODS: Elective inpatients (1,447) and outpatients (563) were randomly assigned to inhalational anesthesia with isoflurane-nitrous oxide or TIVA with propofol-air. Cumulative incidence of postoperative nausea and vomiting was recorded for 72 h by blinded observers. Cost data of anesthetics, antiemetics, disposables, and equipment were collected. Cost differences caused by duration of postanesthesia care unit stay and hospitalization were analyzed. RESULTS: Total intravenous anesthesia reduced the absolute risk of postoperative nausea and vomiting up to 72 h by 15% among inpatients (from 61% to 46%, P < 0.001) and by 18% among outpatients (from 46% to 28%, P < 0.001). This effect was most pronounced in the early postoperative period. The cost of anesthesia was more than three times greater for propofol TIVA. Median duration of stay in the postanesthesia care unit was 135 min after isoflurane versus 115 min after TIVA for inpatients (P < 0.001) and 160 min after isoflurane versus 150 min after TIVA for outpatients (P = 0.039). Duration of hospitalization was equal in both arms. CONCLUSION: Propofol TIVA results in a clinically relevant reduction of postoperative nausea and vomiting compared with isoflurane-nitrous oxide anesthesia (number needed to treat = 6). Both anesthetic techniques were otherwise similar. Anesthesia costs were more than three times greater for propofol TIVA, without economic gains from shorter stay in the postanesthesia care unit

Adult↗
PubMed2001

How disturbing is it to be approached for a genetic cascade screening programme for familial hypercholesterolaemia? Psychological impact and screenees' views.

OBJECTIVES: To assess the screenees' views on, and the psychological impact of, a family-based genetic screening programme for familial hypercholesterolaemia (FH) and to evaluate non-participation. METHODS: Self-administered questionnaires were filled out at the time of screening and after communication of the test result. Non-participants were interviewed by phone. RESULTS: Of the people approached for screening, 2% did not participated. These 2% were not interested, had already been clinically diagnosed, or were afraid of insurance consequences. 677 screenees participated, of whom 215 (32%) tested FH positive. Less than 5% of the screenees were critical of the approach and the information provided. 20% of the screenees expressed feelings of social pressure. Effects on mood were minimal to absent, as were general 'quality of life' effects. CONCLUSIONS: Screening for FH is highly acceptable to screenees, although social pressure is prevalent. Only a small percentage of people being approached did not participate.

Age Factors↗
PubMed2000

A comparison of continuous thalamic stimulation and thalamotomy for suppression of severe tremor.

BACKGROUND: Deep-brain stimulation through an electrode implanted in the thalamus was developed as an alternative to thalamotomy for the treatment of drug-resistant tremor. Stimulation is thought to be as effective as thalamotomy but to have fewer complications. We examined the effects of these two procedures on the functional abilities of patients with drug-resistant tremor due to Parkinson's disease, essential tremor, or multiple sclerosis. METHODS: Sixty-eight patients (45 with Parkinson's disease, 13 with essential tremor, and 10 with multiple sclerosis) were randomly assigned to undergo thalamotomy or thalamic stimulation. The primary outcome measure was the change in functional abilities six months after surgery, as measured by the Frenchay Activities Index. Scores for this index can range from 0 to 60, with higher scores indicating better function. Secondary outcome measures were the severity of tremor, the number of adverse effects, and patients' assessment of the outcome. RESULTS: Functional status improved more in the thalamic-stimulation group than in the thalamotomy group, as indicated by increases in the score for the Frenchay Activities Index (from 31.4 to 36.3 and from 32.0 to 32.5, respectively; difference between groups, 4.4 points; 95 percent confidence interval, 2.0 to 6.9). After adjustment for base-line characteristics, multivariate analysis also showed that the thalamic-stimulation group had greater improvement (difference between groups, 5.1 points; 95 percent confidence interval, 2.3 to 7.9). Tremor was suppressed completely or almost completely in 27 of 34 patients in the thalamotomy group and in 30 of 33 patients in the thalamic-stimulation group. One patient in the thalamic-stimulation group died perioperatively after an intracerebral hemorrhage. With the exception of this incident, thalamic stimulation was associated with significantly fewer adverse effects than thalamotomy. Functional status was reported as improved by 8 patients in the thalamotomy group, as compared with 18 patients in the thalamic-stimulation group (P=0.01). CONCLUSIONS: Thalamic stimulation and thalamotomy are equally effective for the suppression of drug-resistant tremor, but thalamic stimulation has fewer adverse effects and results in a greater improvement in function.

Activities of Daily Living↗
PubMed2000

What is the benefit of preoperative sperm preservation for patients who undergo restorative proctocolectomy for benign diseases?

PURPOSE: In patients with benign colorectal diseases undergoing a restorative proctocolectomy with an ileal pouch-anal anastomosis, semen cryopreservation seems rational to enable the possibility of procreation in case surgery leads to sexual disorders or impotence. The aim of this study was to determine the preoperative and postoperative semen quality in patients undergoing ileal pouch-anal anastomosis. In addition, the study sought to determine the incidence of surgery-induced sexual dysfunction to evaluate the economic efficiency of semen cryopreservation as compared with alternatives such as microsurgical epididymal sperm aspiration. METHODS: Preoperative and postoperative semen analyses were offered to 97 patients with ileal pouch-anal anastomosis with benign colorectal diseases since 1989. The direct costs of the semen cryopreservation program were determined and compared with those of alternatives. RESULTS: In 34 of 40 consecutive patients with ileal pouch-anal anastomosis who made use of preoperative semen preservation, normal sperm concentrations, motility, and morphology were found. Mean semen characteristics of all 23 patients who returned for postoperative analysis were not different from preoperative values, but they were for total sperm number. Two patients developed temporary retrograde ejaculation postoperatively. None of the preserved semen samples was used, thus semen cryopreservation benefited none of these patients. The total costs of semen cryopreservation are between 2.2 and 5 times higher than the costs for one microsurgical epididymal sperm aspiration procedure. CONCLUSIONS: Preoperative semen cryopreservation in patients undergoing ileal pouch-anal anastomosis because of benign colorectal diseases is quite feasible. However, most likely because of improved surgical techniques and the increasing number of effective alternatives, preoperative semen cryopreservation in patients with ileal pouch-anal anastomosis is no longer cost effective.

Adult↗
PubMed2000

The added value that increasing levels of diagnostic information provide in prognostic models to estimate hospital mortality for adult intensive care patients.

OBJECTIVE: To investigate in a systematic, reproducible way the potential of adding increasing levels of diagnostic information to prognostic models for estimating hospital mortality. DESIGN: Prospective cohort study. SETTING: Thirty UK intensive care units (ICUs) participating in the ICNARC Case Mix Programme. PATIENTS: Eight thousand fifty-seven admissions to UK ICUs. MEASUREMENTS AND RESULTS: Logistic regression analysis incorporating APACHE II score, admission type and increasing levels of diagnostic information was used to develop models to estimate hospital mortality for intensive care patients. The 53 UK APACHE II diagnostic categories were substituted with data from a hierarchical, five-tiered (type of condition required surgery or not, body system, anatomical site, physiological/pathological process, condition) coding method, the ICNARC Coding Method. The inter-rater reliability using the ICNARC Coding Method to code reasons for admission was good (kappa = 0.70). All new models had good discrimination (AUC = 0.79-0.81) and similar or better calibration compared with the UK APACHE II model (Hosmer-Lemeshow goodness-of-fit H = 18.03 to H = 26.77 for new models versus H = 63.51 for UK APACHE II model). CONCLUSION: The UK APACHE II model can be simplified by extending the admission type and substituting the 53 UK APACHE II diagnostic categories with nine body systems, without losing discriminative power or calibration.

APACHE↗
PubMed2000

Cost-effectiveness of in vitro fertilization and embryo transfer.

OBJECTIVE: Economic analyses in reproductive medicine often fail to take into account the chances of treatment-independent conception. We compared the cost-effectiveness of several realistic strategies involving IVF using no treatment as the reference strategy. DESIGN: A decision tree was constructed for a subfertile couple in which the clinician had to decide whether to offer treatment with IVF. No treatment at all was used as the reference strategy. SETTING: An analytic decision-making framework. PATIENT(S): Hypothetical subfertile couples. INTERVENTION(S): Two potential treatment approaches: three IVF cycles performed as soon as possible, or no treatment performed initially and then three or four IVF cycles performed if a pregnancy resulting in a live birth does not occur naturally after 212 years. MAIN OUTCOME MEASURE(S): The cost of establishing one pregnancy that results in a live birth. RESULT(S): The cost-effectiveness of IVF depended not only on the costs and expected success rates of IVF itself but also on the couple-specific chances of treatment-independent conception. Consequently, the cost-effectiveness of IVF is strongly dependent on the age of the female partner. This finding corresponds with everyday clinical experience. CONCLUSION(S): Economic analyses in reproductive medicine should take into account the option of providing no treatment.

Adult↗
PubMed2000

Comparing treatment valuations between and within subjects in clinical trials: does it make a difference?

Valuations may be sensitive to biases, especially if elicited alongside randomized clinical trials. We investigated the construction of valuations assigned by women who entered a randomized clinical trial and were allocated to in-hospital or domiciliary monitoring. Women assigned valuations (0-10 visual analogue scale) to the strategy they had been allocated to and to the alternative strategy. Valuations were expressed as a between-subject difference (assigned by the women allocated to the respective strategies) and as within-subject differences (assigned by all women). Domiciliary monitoring was valued higher by the women allocated to that strategy (P = 0.10). In-hospital monitoring was valued higher by the women allocated to that strategy (P = 0.02). The average within-subject differences differed by allocated strategy (P<0.01). The within-subject valuation differences showed large variability between and within groups. An overrepresentation of women favoring domiciliary monitoring and asymmetric treatment experience inflated the average within-subject difference in the domiciliary group but deflated that difference in the in-hospital group. Neither the average between-subject difference nor the average within-subject differences are free of bias. Other study designs probably cannot prevent bias. Comparing within-subject and between-subject differences is instructive.

Adult↗
PubMed1999

Empirical evidence of design-related bias in studies of diagnostic tests.

CONTEXT: The literature contains a large number of potential biases in the evaluation of diagnostic tests. Strict application of appropriate methodological criteria would invalidate the clinical application of most study results. OBJECTIVE: To empirically determine the quantitative effect of study design shortcomings on estimates of diagnostic accuracy. DESIGN AND SETTING: Observational study of the methodological features of 184 original studies evaluating 218 diagnostic tests. Meta-analyses on diagnostic tests were identified through a systematic search of the literature using MEDLINE, EMBASE, and DARE databases and the Cochrane Library (1996-1997). Associations between study characteristics and estimates of diagnostic accuracy were evaluated with a regression model. MAIN OUTCOME MEASURES: Relative diagnostic odds ratio (RDOR), which compared the diagnostic odds ratios of studies of a given test that lacked a particular methodological feature with those without the corresponding shortcomings in design. RESULTS: Fifteen (6.8%) of 218 evaluations met all 8 criteria; 64 (30%) met 6 or more. Studies evaluating tests in a diseased population and a separate control group overestimated the diagnostic performance compared with studies that used a clinical population (RDOR, 3.0; 95% confidence interval [CI], 2.0-4.5). Studies in which different reference tests were used for positive and negative results of the test under study overestimated the diagnostic performance compared with studies using a single reference test for all patients (RDOR, 2.2; 95% CI, 1.5-3.3). Diagnostic performance was also overestimated when the reference test was interpreted with knowledge of the test result (RDOR, 1.3; 95% CI, 1.0-1.9), when no criteria for the test were described (RDOR, 1.7; 95% CI, 1.1-2.5), and when no description of the population under study was provided (RDOR, 1.4; 95% CI, 1.1-1.7). CONCLUSION: These data provide empirical evidence that diagnostic studies with methodological shortcomings may overestimate the accuracy of a diagnostic test, particularly those including nonrepresentative patients or applying different reference standards.

Bias↗
PubMed1999

[No consensus on the definition, diagnosis and treatment of habitual abortion in the Netherlands].

OBJECTIVE: To review the current policy in diagnosis and treatment of recurrent miscarriage in the Netherlands. DESIGN: Cross-sectional survey. METHOD: A printed questionnaire was sent in 1996 to all 125 departments of gynaecology in the Netherlands with questions about definition, investigation and therapy of recurrent miscarriage. RESULTS: The response rate was 90% (n = 112). Twenty-nine per cent of the respondents defined recurrent miscarriage as having two or more abortions and 71% as three or more abortions. In 42% of the departments a diagnostic protocol for recurrent miscarriage was present. Diagnostic investigations most frequently performed were vaginal ultrasound (79%), parental chromosome analysis (78%), thyroid-stimulating hormone (72%), lupus anticoagulant (69%), blood glucose (65%), hysterosalpingography (56%) and anticardiolipin antibodies (IgG, IgM) (56%). Therapy most frequently applied was prescription of folic acid (53%). CONCLUSION: The definition of recurrent miscarriage differed. Uncertainty about a rational diagnostic approach was evident from the large number of tests requested by 20-50% of the respondents. Some diagnostic tests like immunological investigation and search for infectious factors were not followed by a therapeutical intervention.

Abortion, Habitual↗
PubMed1999

Interobserver variability of the neurological optimality score.

OBJECTIVE: To assess the interobserver reliability of the neurological optimality score. STUDY DESIGN: The neurological optimality score of 21 full term healthy, neurologically normal newborn infants was determined by two well trained observers. RESULTS: The interclass correlation coefficient was 0.31. Kappa for optimality (score of 58 or higher) was 0.19. A systematic difference of 1.3 points between the two observers was present. CONCLUSIONS: The interobserver variability of the neurological optimality score of the newborn infant is substantial. The subtle judgement of elicited responses as optimal or non-optimal proved to be especially critical in this concordance study. A difference of at least two points in the score is considered as a valid endpoint for comparative studies. If two or more observers are involved in the neurological examination of the newborn infant in a study to assess influences on perinatal morbidity, frequent re-instruction sessions are recommended.

Birth Weight↗
PubMed1999

The effect of adding a cognitive dimension to the EuroQol multiattribute health-status classification system.

A methodological study was conducted to examine the effect of extending a frequently used simple multiattribute health-status classification system by adding a cognitive dimension. The EQ-5D questionnaire is a generic instrument to value health, developed by the EuroQol Group. The EQ-5D defines health according to five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. We defined 18 different health states according to the standard EQ-5D classification. A second set of health states was constructed similar to the first, except for the addition of a cognitive dimension (EQ-5D+C). Valuations of both sets of health states were statistically analyzed to detect the effect of the additional dimension. The cognitive dimension generated systematically different values compared with the standard EQ-5D version, whereas the content validity improved. Both systems evoked equally reliable values. Analyses showed that a simple additive model to predict summary values for health states was not optimal for both systems. Although there is a current lack of consensus regarding the domains that are selected to represent health status, this study has shown the importance of considering the inclusion of a cognitive domain.

Activities of Daily Living↗
PubMed1999

Cardiovascular disease in the Netherlands, 1975 to 1995: decline in mortality, but increasing numbers of patients with chronic conditions.

OBJECTIVE: To examine the relation between trends over time in mortality and hospital morbidity caused by various cardiovascular diseases in the Netherlands. DESIGN: Trend analysis by Poisson regression of national data on mortality and hospital admissions from 1975 to 1995. SUBJECTS: The Dutch population. RESULTS: All cardiovascular diseases combined were responsible for 39% of all deaths and 16% of all hospital admissions in 1995. From 1975 to 1995, age adjusted cardiovascular mortality declined by an annual change of -2.0% (95% confidence intervals (CI) -2.1% to -1.9%), while in the same period age adjusted discharge rates increased annually by 1. 3% (95% CI 1.1% to 1.5%). Around 60% of the gain in life expectancy in this period was related to lower cardiovascular mortality. For mortality, major reductions were seen in coronary heart disease (annual change -2.9%) and in stroke (-2.1%), whereas the increase in hospital admissions was mainly caused by chronic manifestations of coronary heart disease (5.1%), heart failure (2.1%), and diseases of the arteries (1.8%). In recent years, the gap between men and women at risk of dying from coronary heart disease became smaller for those aged </= 65 years. CONCLUSIONS: Our findings of a decrease in cardiovascular mortality and an increase in admission rates for chronic conditions such as heart failure, chronic coronary syndromes, and diseases of the arteries, support the hypothesis that the longer survival of many patients with heart diseases is leading to a growing pool of patients at increased risk for subsequent cardiovascular complications in Western countries.

Adolescent↗
PubMed1999

MR angiography as a screening tool for intracranial aneurysms: feasibility, test characteristics, and interobserver agreement.

OBJECTIVE: MR angiography may be an appropriate tool to screen for unruptured intracranial aneurysms. Feasibility, test characteristics, and interobserver agreement in evaluation of MR angiograms were assessed by members of the MARS (Magnetic resonance Angiography in Relatives of patients with Subarachnoid hemorrhage) Study Group. SUBJECTS AND METHODS: We screened 626 first-degree relatives of a consecutive series of 193 patients with subarachnoid hemorrhage examined at two institutions. We used MR imaging and MR angiography (three-dimensional time-of-flight imaging at both institutions and additional three-dimensional phase-contrast imaging at one institution). Three observers independently assessed the MR angiograms. Conventional angiography was performed in relatives with possible or definite aneurysms on MR angiography and was considered the standard of reference. RESULTS: Thirty-three aneurysms were found in 25 (4%; 95% confidence interval [CI], 3-6%) of 626 relatives. Thirteen (8%) of 169 relatives who refused screening had MR-related reasons; an additional six persons could not be screened because of contraindications for MR imaging (pregnancy, n = 1; claustrophobia, n = 5). The positive predictive value of MR angiography was 100% (95% CI, 79-100%) for "definite" aneurysms and 58% (95% CI, 28-85%) for "possible" aneurysms. Sensitivity of MR angiography was estimated at 83% (95% CI, 65-94%) and specificity at 97% (95% CI, 94-98%). Interobserver agreement in the evaluation of MR angiograms was poor (kappa < .30), probably because different diagnostic strategies used by individual observers resulted in different use of the assessment category "possible aneurysm." CONCLUSION: MR angiography is a feasible screening tool for detection of intracranial aneurysms. Positive predictive value, sensitivity, and specificity are acceptable when at least two neuroradiologists independently assess MR angiograms.

Adult↗