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G J Bonsel

Publications and source records attributed to G J Bonsel.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Evaluation of drugs: efficacy, applicability, effectiveness and efficiency].

In view of rising costs of drugs and the limited budget, government, institutes, researchers, prescribers, pharmacists and pharmaceutical industries should have a standardized assessment system at their disposal on which to base their pharmacotherapeutic policy. Evaluation can be achieved in four successive steps, taking into account both therapeutical and financial aspects. The first two steps, determining efficacy and applicability, represent the current system of evaluating drugs before allowance to the market. Steps 3 and 4 describe the ways in which effectiveness and efficiency can be involved in the evaluation by means of (cost) effectiveness analysis. Achieving optimal results from this stepwise approach requires speedy acceptance of the currently available guidelines for effective and efficient research.

Cost-Benefit Analysis↗
PubMed1998

The relation between TISS and real paediatric ICU costs: a case study with generalizable methodology.

OBJECTIVE: To determine the quantitative relation between the Therapeutic Intervention Scoring System (TISS) in combination with other relevant clinical variables and the real costs of (paediatric) intensive care. DESIGN: A prospective, observational study. SETTING: A Ten-bed paediatric intensive care unit in a university children's hospital. PATIENTS AND PARTICIPANTS: In a 17-months registration period we collected patient- and treatment-related data for all 611 consecutive admissions. A 21-day calibration period was used to collect detailed data to calculate the real costs of 33 consecutive admissions, in addition to the same data as in the registration period. MEASUREMENTS AND RESULTS: We used the Multi Moment Measurement method to measure time spent by nurses and physicians and medication used in the 21-day calibration period. The calibration period data set with explanatory variables including TISS was used to build a regression model to estimate nurse and physician time, which were converted to personnel costs, and to estimate medication costs. The regression models built from the calibration period were subsequently used to estimate the total costs per day and per admission in different patient groups in the registration period. CONCLUSION: It was feasible to calculate total direct medical costs based on a limited number of readily available clinical variables related to patient characteristics and treatment, of which TISS was the most important determinant. The proposed methods provide further tools for assessment of (paediatric) intensive care unit performance.

Direct Service Costs↗
PubMed1998

Intensification of fetal and maternal surveillance in pregnant women with hypertensive disorders.

OBJECTIVE: To examine the need to intensify fetal and maternal surveillance in pregnant women with mild pregnancy hypertension. METHODS: The multi-center cohort study in 2413 healthy nulliparae analyzed differences in hypertension-related adverse events (small-for-gestational age, perinatal mortality, eclampsia, abruptio placentae and HELLP syndrome) according to maximum diastolic blood pressure and proteinuria. RESULTS: Compared to the reference group (diastolic blood pressure 70-85 mmHg) (n = 1882) the relative risks of adverse fetal and maternal outcome in 34 proteinuric hypertensive women were 8.9 (95% CI 3.3-24.1) and 41.5 (95% CI 9.7-178.4), respectively. In 203 non-proteinuric women with a maximum diastolic blood pressure of > or = 95 mmHg only the relative risk of adverse maternal outcome was increased (11.6, 95% CI 3.1-42.8), but it was not increased in 230 non-proteinuric women with a maximum diastolic of 90 mmHg. CONCLUSIONS: Intensified surveillance in women with mild pregnancy hypertension is not indicated and should be reserved for groups with increased fetal and maternal risk.

Female↗
PubMed1998

Risk factors for preeclampsia in nulliparous women in distinct ethnic groups: a prospective cohort study.

OBJECTIVE: To determine whether baseline characteristics during early pregnancy, proposed as potential risk factors for preeclampsia, show differences in prevalence and effects within distinct ethnic groups. METHODS: In a prospective cohort study of 2413 healthy nulliparous women from eight midwives' practices, we analyzed risk factors for preeclampsia (maternal age, body mass index, blood pressure at booking, smoking habit, and abortion history) in white, Mediterranean, Asian, and black women. In a univariate analysis, we estimated the relative risk of preeclampsia for the baseline variables and for ethnicity. In a multivariate analysis, we evaluated the simultaneous effect of the baseline variables in white (n = 1641) and black (n = 317) women. RESULTS: Significant differences were found in the prevalence of the risk factors in different ethnic groups. In the univariate analysis, the relative risk (RR) of preeclampsia in black women was 2.4 (95% confidence interval [CI] 1.1, 5.6) compared with white women. In the multivariate analysis in white women, the adjusted RR of preeclampsia for a diastolic blood pressure at booking above 70 mmHg was 4.4 (CI 0.9, 20.8). Among black women, the adjusted RR of preeclampsia was increased for high maternal age (RR 1.2; CI 1.0, 1.4), but not for a diastolic blood pressure at booking above 70 mmHg (RR 0.8; CI 0.2, 3.9). CONCLUSION: In studies of risk factors for preeclampsia, black women should be analyzed separately from white women.

Adult↗
PubMed1998

Maternal and perinatal outcome after expectant management of the HELLP syndrome compared with pre-eclampsia without HELLP syndrome.

OBJECTIVE: To compare maternal and perinatal outcome of pregnancies complicated by pregnancy induced hypertension and HELLP syndrome with the outcome of pregnancies complicated by pre-eclampsia only. DESIGN: It was a retrospective cohort study. Fifty one patients with pregnancy induced hypertension and HELLP syndrome were matched with 51 pre-eclamptic patients according to parity and gestational age on admission in hospital. Management was expectant, treatment only symptomatic and delivery was mainly effectuated because of fetal condition. RESULTS: There was no maternal mortality in either group; maternal morbidity was more frequent in the HELLP group. Immediate intervention within a few hours of admission because of fetal distress more often occurred in the HELLP group. In both groups 41 children (80%) are still alive, with one major handicapped child in each group. Logistic regression analysis identified gestational age on admission and antihypertensive treatment on admission as significant contributors to perinatal mortality or major handicap. Whether the patient belonged to the HELLP group or the pre-eclamptic group had no influence on outcome. CONCLUSION: Expectant management of pregnancy induced hypertension with HELLP syndrome and pre-eclampsia without HELLP syndrome results in similar maternal and perinatal outcome. Perinatal outcome is strongly influenced by gestational age and the severity of hypertension as expressed by the need of antihypertensive treatment, irrespective of the underlying syndrome.

Adolescent↗
PubMed1998

Within-subject variability of differences between conventional and automated blood pressure measurements in pregnancy.

OBJECTIVE: To determine whether measured differences between standard mercury sphygmomanometry and the SpaceLabs 90207 ambulatory blood pressure monitor in pregnant women remain constant during 24 h measurements. STUDY DESIGN: Repeated comparisons between standard mercury sphygmomanometry and Spacelabs 90207 were performed at nine predetermined time points during 24 h ambulatory blood pressure measurements in a group of ten pregnant women with various pregnancy complications, including hypertension. Individual and group differences between standard mercury sphygmomanometry and SpaceLabs 90207 were calculated for each time point. Friedman's ANOVA was used to test stability of differences across time. RESULTS: Mean group differences (standard deviation) between mercury sphygmomanometry and the SpaceLabs 90207 were -2 (6) mmHg and 3 (7) mmHg for systolic and diastolic pressure respectively. For systolic pressure the differences between time points were not statistically significant. Although a statistical significant trend was found for diastolic pressure differences (P<0.05), none of the contrasts between any pair of time points reached statistical significance. For both systolic and diastolic pressure the minimal and maximal difference lay at least 10 mmHg apart in seven patients. CONCLUSIONS: Despite standardisation and training, a substantial within-subject variability of the pressure difference between observers and SpaceLabs was found in this heterogeneous group of women. However, a systematic time-related effect on this pressure difference could not be demonstrated. The pressure difference between both methods cannot be estimated with great precision. This is a serious impediment for the clinical interpretation of automated or ambulatory blood pressure data.

Adult↗
PubMed1998

Technology assessment of the Dutch Lung Transplantation Program.

The costs, effects, and cost-effectiveness of the Dutch Lung Transplantation program were assessed. The results show that lung transplantation is a very costly intervention that improves survival and quality of life. Costs per life-year and per QALY gained were, respectively, US $90,000 and US $71,000.

Algorithms↗
PubMed1998

Low sodium diet and pregnancy-induced hypertension: a multi-centre randomised controlled trial.

OBJECTIVE: To examine the effectiveness of the standard policy in the Netherlands to prescribe a sodium restricted diet to prevent or to treat mild pregnancy-induced hypertension. DESIGN: Multi-centre randomised controlled trial between April 1992 and April 1994. SETTING: Seven practices of independent midwives and one university hospital. PARTICIPANTS: The experimental group comprised 184 women given a low sodium diet (< or = 50 mmol sodium/day) and a control group of 177 women given a normal diet. Eligible women for inclusion had had a rise of blood pressure, or excessive weight gain or oedema during the antenatal period. The 361 women in the trial were recruited from 2020 nulliparae, of whom 1512 (75%) gave informed consent at the beginning of their pregnancy to participate in the study. MAIN OUTCOME MEASURES: The difference between highest diastolic blood pressure after randomisation and diastolic blood pressure at the moment of randomisation; referral and admission to hospital for hypertension. RESULTS: There was no difference in increase of diastolic blood pressure after randomisation, the percentage of referral and admission to hospital for hypertension, or in obstetric outcome between the two groups. Urinary sodium excretion after randomisation in the normal diet group was significantly higher than in the low sodium group. CONCLUSION: Prescribing a sodium-restricted diet to prevent or to treat mild pregnancy-induced hypertension is not effective. Therefore there is no need to introduce a salt restricted diet in prenatal care, although increasing evidence shows that a low sodium diet prevents hypertension in non-pregnant individuals.

Adult↗
PubMed1998

Epidemiology of stroke in The Netherlands from 1972 to 1994: the end of the decline in stroke mortality.

In 1994, stroke was responsible for the death of 4,994 men and 7,601 women in the Netherlands, corresponding to 7.5% of all deaths in men and 11.4% in women. Age-adjusted stroke mortality declined by 39% for men and by 45% for women between 1972 and 1994. However, the decline in mortality levelled off after 1987. In contrast to mortality, age-adjusted discharge rates increased by 47% for men and by 28% for women during the study period. The decline in mortality was equally distributed over the age groups, while the increase in the number of hospital admissions was more pronounced in the older age groups. The analyses by diagnostic subgroups of stroke showed the importance of increasing diagnostic capabilities in the hospital setting. The use of diagnostic subgroups in national mortality data was of limited value, illustrated by the fact that 70% of all stroke deaths in 1994 belonged to the ill-defined type of stroke.

Age Distribution↗
PubMed1998

Does lung transplantation prolong life? A comparison of survival with and without transplantation.

BACKGROUND: Because of the assumed beneficial effect of lung transplantation on survival, controlled trials to assess the therapeutic benefit of lung transplantation are considered to be unethical. Therefore other methods must be used to provide control data. In this study the effect of lung transplantation on survival for patients with end-stage pulmonary disease was analyzed, with waiting list survival rates used as control data. METHODS: The analysis was based on 157 consecutive patients who were put on the waiting list of the Dutch lung transplantation program during the period November 1990 to January 31, 1996, of whom 76 underwent transplantation. Following the principles of control group estimation as set out in the context of heart transplantation, a stepwise approach was used to arrive at a multivariate time-dependent Cox regression model. The following prognostic variables were included in the analyses: age, forced expiratory volume in 1 second, partial pressure of carbon dioxide, partial pressure of oxygen, and diagnosis. RESULTS: The 1- and 2-year waiting list survival rates were 78% and 58%, respectively. The 1- and 2-year transplantation survival rates (i.e., survival from placement on the waiting list, including posttransplantation survival) were 79% and 64%, respectively. The multivariate time-dependent Cox analysis showed that lung transplantation reduced the risk of dying by 55% (95% confidence interval, 3% to 79%). For patients with emphysema the risk of dying was estimated to be 77% lower than for patients with other diagnoses (96% confidence interval, 50% to 89%). CONCLUSIONS: With Cox regression, adjusting for age, forced expiratory volume in 1 second, partial pressure of carbon dioxide, partial pressure of oxygen, and diagnosis, lung transplantation showed a statistically significant effect on survival in selected patients with end-stage pulmonary disease.

Adult↗
PubMed1997

Cost-minimization analysis of domiciliary antenatal fetal monitoring in high-risk pregnancies.

OBJECTIVE: To compare safety and cost-effectiveness of domiciliary antenatal fetal monitoring (cardiotocography and obstetric surveillance) with in-hospital monitoring in high-risk pregnancies. METHODS: From September 1992 to June 1994, 150 consecutive women with high-risk pregnancies, who would otherwise be monitored in the hospital, entered a randomized controlled trial of in-hospital (n = 74) or domiciliary (n = 76) monitoring. The main outcome measures were neonatal safety (Prechtl neurologic optimality score, the proportion of non-optimals) and cost-effectiveness. To test a two-point difference in mean Prechtl scores (two-tailed o = .05. 1-beta = .80), 150 women were needed. Safety and cost-effectiveness were analyzed according to intention to treat. Conditional on the safety outcomes, a cost-minimization analysis based on actual resource use was performed. Uncertainty of results was explored by sensitivity analyses. RESULTS: Neonatal outcomes were equal. No cost-shifting between the antenatal and postpartum period occurred. Substituting domiciliary for in-hospital monitoring reduced mean (standard deviation) antenatal costs from $3558 ($2841) to $1521 ($1459) per woman (P < .001). If costs were varied by the addition of 50%, costs were still reduced. The magnitude of the reduction was sensitive to the costs of hospital care and less sensitive to the costs of domiciliary monitoring. CONCLUSION: Domiciliary monitoring is safe and reduces costs by one-half. The technique seems transferable to other settings but local circumstances may sometimes hamper its dissemination.

Adult↗
PubMed1997

The comparability and reliability of five health-state valuation methods.

The objective of the study was to consider five methods for valuing health states with respect to their comparability (convergent validity, value functions) and reliability. Valuation tasks were performed by 104 student volunteers using five frequently used valuation methods: standard gamble (SG), time trade-off (TTO), rating scale (RS), willingness-to-pay (WTP) and the paired comparisons method (PC). Throughout the study, the EuroQol classification system was used to construct 13 health-state descriptions. Validity was investigated using the multitrait-multimethod (MTMM) methodology. The extent to which results of one method could be predicted by another was examined by transformations. Reliability of the methods was studied parametrically with Generalisability Theory (an ANOVA extension), as well as non-parametrically. Mean values for SG were slightly higher than TTO values. The RS could be distinguished from the other methods. After a simple power transformation, the RS values were found to be close to SG and TTO. Mean values of WTP were linearly related to SG and TTO, except at the extremes of the scale. However, the reliability of WTP was low and the number of inconsistencies substantial. Valuations made by the RS proved to be the most reliable. Paired comparisons did not provide stable results. In conclusion, the results of the parametric transformation function between RS and SG/TTO provide evidence to justify the current use of RS (with transformations) not only for reasons of feasibility and reliability but also for reasons of comparability. A definite judgement on PC requires data of a complete design. Due to the specific structure of the correlation matrix which is inherent in valuing health states, we believe that full MTMM is not applicable for the standard analysis of health-state valuations.

Adult↗
PubMed1997

Health status prediction in critically ill children: a pilot study introducing Standardized Health Ratios.

Performance of intensive care is usually quantified by means of standardized mortality rates, where standardization is directed towards the severity of illness on admission. However, as more critically ill patients survive, functional outcome and quality of life of these patients becomes more important. In a prospective study in a 10-bed tertiary paediatric intensive care unit (ICU), admission and follow-up health status were collected for 209 surviving patients. For this cohort of patients, health status 1 year after admission was also predicted, using the quantified health-utility-index (HUI), as a value between 0 and 1. For this purpose, two alternative multiple regression models were constructed. The most important predictors of 1-year health status were the level of sensation, mobility and cognition on admission to which self-care, systolic blood pressure, oxygen, Glascow Coma Scale, glucose and age may be added. The two alternative predictive models performed equally well (R2 = 0.83 and 0.84 respectively), indicating that health status could be predicted to a significant degree. The concept of relating expected future health status (based on base-line health status), with actual (observed) health status is denoted with the Standardized Health Ratio (SHR). In combination with the Standardized Mortality Ratios (SMR), such a ratio may become a new comprehensive indicator of performance in intensive care medicine.

Adolescent↗
PubMed1997

Additive or sequential nucleoside analogue therapy compared with continued zidovudine monotherapy in human immunodeficiency virus-infected patients with advanced disease does not prolong survival: an observational study.

To study the effect of sequential or additive use of zalcitabine or didanosine on survival in 308 human immunodeficiency virus-infected patients with advanced disease treated with zidovudine, an observational study using time-dependent Cox proportional hazards models was done. Changing to sequential or additive therapy was based on deterioration of a patient's health status, a significant drop in CD4 cell count, or intolerance for zidovudine. The median CD4 cell count at baseline was 110 x 10(6)/L; 42% of patients had AIDS. The median count before a change in therapy was 50 x 10(6)/L. Additive or sequential treatment was associated with an increased risk for death (relative hazard, 1.59; 95% confidence interval [CI], 1.01-2.49; and 1.58; 95% CI, 1.10-2.37, respectively). Adjustment of the models for prognostic factors failed to substantially affect this observation. Possibly the lack of benefit in this study is because patients switched therapy at advanced stages, whereas the switch may be more effective in early disease.

Adult↗
PubMed1997

An empirical comparison of four generic health status measures. The Nottingham Health Profile, the Medical Outcomes Study 36-item Short-Form Health Survey, the COOP/WONCA charts, and the EuroQol instrument.

OBJECTIVES: An empirical, head-to-head comparison of the performance characteristics of four generic health status measures. METHODS: The Nottingham Health Profile, the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36), the COOP/WONCA charts, and the EuroQol instrument were simultaneously employed in a controlled survey measuring the impact of migraine on health status. The feasibility (number of missing cases per item), internal consistency (Cronbach's alpha), construct validity (correlation patterns and common factor analysis), and discriminative ability (Receiver Operating Characteristics analyses) of the four measures were investigated. RESULTS: The Nottingham Health Profile produced the lowest missing value rate. The internal consistency of the Nottingham Health Profile scales was lower than the scales of the SF-36. Combined factor analyses with data of the four instruments together resulted in two-factor solutions with a physical and a mental factor, explaining approximately 50% of variance. The SF-36 exhibited the best ability to discriminate between groups. Test-retest reliability and sensitivity to change over time could not be tested because of the cross-sectional character of the study. CONCLUSIONS: None of the instruments performed uniformly as "best" or "worst." Purely on the basis of the results of the psychometric analyses, the SF-36 appeared to be the most suitable measure of health status in this relatively healthy population. In general, the choice of the most suitable instrument for generic health status assessment in a particular study should be guided by the special features of each candidate instrument under consideration.

Adult↗
PubMed1996

NHP or SIP--a comparative study in renal insufficiency associated anemia.

In this study we compared the feasibility, internal structure and psychometric characteristics (internal consistency, test-retest reliability, construct validity) of two widely used generic health status measures, i.e. the Nottingham Health Profile (NHP) and the Sickness Impact Profile (SIP) when employed among a sample of patients on renal dialysis (n = 63). The NHP was found to be more feasible, i.e. shorter and less difficult, than the SIP. The NHP scales showed somewhat higher levels of internal consistency (mean alpha = 0.67, range = 0.39-0.80) than the SIP scales (mean alpha = 0.65, range = 0.14-0.82). Test-retest reliability with a 24-hour interval was acceptable for most NHP scales (not available for the SIP in this study). Intercorrelations between the NHP scales were somewhat weaker than those for the SIP, and the expected patterns of scale intercorrelations were largely confirmed. The overall pattern of correlations between NHP scales and SIP scales was consistent with expectations, although the correlations were generally rather weak. Correlations between NHP scales and SIP scales and instruments measuring mainly physical functioning (ADL, Karnofsky) were largely as expected. Similarly, correlations between NHP scales and SIP scales and instruments measuring mainly psychological functioning [STAI (anxiety), SDS-Zung (depression)] were also as expected, although here the correlations were weaker for the SIP when compared with the NHP. The Index of Well-being exhibited intra-class correlations > 0.3 with one SIP scale and with five out of six NHP scales. Common factor analysis, yielding a two-factor solution with a physical and a mental factor of equal importance, showed the SIP scales to load more on the physical factor, while the NHP scales loaded more on the mental factor. The NHP generally performed better than the SIP in terms of feasibility and internal consistency. Physical functioning is emphasized in the SIP, whereas the emphasis of the NHP lies on mental functioning. The analysis confirmed to some extent the intentions of the constructors of NHP and SIP respectively, i.e. the NHP to be a measure of perceived health and the SIP to be a more functional measure.

Adult↗
PubMed1996

Reliability and validity of a comprehensive health status measure in a heterogeneous population of children admitted to intensive care.

This study assesses psychometric and empirical characteristics of the Multi-Attribute Health Status Classification (MAHSC) in a heterogeneous population of children admitted to intensive care. The MAHSC encompasses six health domains (sensation, mobility, emotion, cognition, self-care, and pain), each with four or five hierarchic levels of dysfunction. The health status of 254 consecutively admitted children was determined independently by 3 different observers (parents, attending clinicians, and investigators). The proportion of children with health impairment varied between 13% (in sensation) and 58.7% (in mobility). Interrater reliability of domain scores, as analyzed by Spearman's rank, Pearson product moment, and intraclass correlations, was high, generally exceeding 0.80 for all pairs of observers. Intraclass correlation appeared to be highest in nonsurgical patients (range, 0.89-0.98) and lowest in cardiovascular surgery patients (range, 0.50-0.84). The validity of the classification was supported by (1) the presence of expected specific health status impairment in patient suffering from diseases with an acknowledged impact on specific domains and (2) the presence of a relation between health impairment and medical consumption. The absence of a relation between the average (chronic) health status preceding admission and the acute risk of mortality precipitating the admission confirmed their independent prominence in outcome assessment. We conclude that the MAHSC is a feasible, reliable, and valid measure for outcome assessment in a heterogeneous population of children within a demanding clinical situation. Excellent interrater reliability allows the use of various raters, adjusted to practical requirements.

Adolescent↗