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Data Interpretation, Statistical↗
Biomedical subjects
Gert Jan van der Wilt
Publications and source records attributed to Gert Jan van der Wilt.
Design of the PROCON trial: a prospective, randomized multi-center study comparing cervical anterior discectomy without fusion, with fusion or with arthroplasty.
BACKGROUND: PROCON was designed to assess the clinical outcome, development of adjacent disc disease and costs of cervical anterior discectomy without fusion, with fusion using a stand alone cage and implantation of a Bryan's disc prosthesis. Description of rationale and design of PROCON trial and discussion of its strengths and limitations. METHODS/DESIGN: Since proof justifying the use of implants or arthroplasty after cervical anterior discectomy is lacking, PROCON was designed. PROCON is a multicenter, randomized controlled trial comparing cervical anterior discectomy without fusion, with fusion with a stand alone cage or with implantation of a disc. The study population will be enrolled from patients with a single level cervical disc disease without myelopathic signs. Each treatment arm will need 90 patients. The patients will be followed for a minimum of five years, with visits scheduled at 6 weeks, 3 months, 12 months, and then yearly. At one year postoperatively, clinical outcome and self reported outcomes will be evaluated. At five years, the development of adjacent disc disease will be investigated. DISCUSSION: The results of this study will contribute to the discussion whether additional fusion or arthroplasty is needed and cost effective.
Adolescent↗
Comparison of laparoscopic and mini incision open donor nephrectomy: single blind, randomised controlled clinical trial.
OBJECTIVES: To determine the best approach for live donor nephrectomy to minimise discomfort to the donor and to provide good graft function. DESIGN: Single blind, randomised controlled trial. SETTING: Two university medical centres, the Netherlands. PARTICIPANTS: 100 living kidney donors. INTERVENTIONS: Participants were randomly assigned to either laparoscopic donor nephrectomy or to mini incision muscle splitting open donor nephrectomy. MAIN OUTCOME MEASURES: The primary outcome was physical fatigue using the multidimensional fatigue inventory 20 (MFI-20). Secondary outcomes were physical function using the SF-36, hospital stay after surgery, pain, operating times, recipient graft function, and graft survival. RESULTS: Conversions did not occur. Compared with mini incision open donor nephrectomy, laparoscopic donor nephrectomy resulted in longer skin to skin time (median 221 v 164 minutes, P < 0.001), longer warm ischaemia time (6 v 3 minutes, P < 0.001), less blood loss (100 v 240 ml, P < 0.001), and a similar number of complications (intraoperatively 12% v 6%, P = 0.49, postoperatively both 6%). After laparoscopic nephrectomy, donors required less morphine (16 v 25 mg, P = 0.005) and shorter hospital stay (3 v 4 days, P = 0.003). During one year's follow-up mean physical fatigue was less (difference - 1.3, 95% confidence interval - 2.4 to - 0.1) and physical function was better (difference 6.2, 2.0 to 10.3) after laparoscopic nephrectomy. Function of the graft and graft survival rate of the recipient at one year censored for death did not differ (100% after laparoscopic nephrectomy and 98% after open nephrectomy). CONCLUSIONS: Laparoscopic donor nephrectomy results in a better quality of life compared with mini incision open donor nephrectomy but equal safety and graft function.
Adult↗
Non-compliance on the part of the professional community with a national guideline: an argumentative policy analysis.
In 1997, the National Health Insurance Board of the Netherlands (CVZ) introduced a guideline for the use of a new anti-epileptic drug, Lamotrigine. The goal was to limit the use of this relatively expensive drug to patients with difficult-to-treat epilepsy. A survey had shown that only a minority of neurologists were familiar with the guideline, and even fewer applied it in practice. In the present study, interviews were held with stakeholders to obtain a better understanding of why this policy measure failed. The results indicate that the problem definitions of policy maker and practicing neurologists differed widely, and that the policy measure was conflicting with certain professional beliefs. In such cases, the theory of argumentative policy predicts that policy is unlikely to succeed, unless policy makers take actions to ensure a greater congruence in interpretative frames between them and their target population.
Anticonvulsants↗
Can the Memorial Sloan-Kettering Cancer Center nomogram predict the likelihood of nonsentinel lymph node metastases in breast cancer patients in the Netherlands?
BACKGROUND: According to Dutch guidelines, an axillary lymph node dissection (ALND) is recommended whenever a sentinel lymph node (SLN) contains metastatic disease. However, only in approximately 50% of patients with metastatic disease in the SLN are additional nodal metastases detected in the completion ALND. To identify the individual patient's risk for non-SLN metastases, a nomogram containing eight predictors was developed by the Breast Service of Memorial Sloan-Kettering Cancer Center (New York, NY). The aim of this study was to test the accuracy of the nomogram on a population of Dutch breast cancer patients. METHODS: Patient, tumor, and SLN metastasis characteristics were collected for 222 consecutive patients who underwent a completion ALND. The data of the index and test populations were compared. A receiver operating characteristic curve was drawn, and the area under the curve was calculated to assess the discriminative power of the nomogram. RESULTS: Even though our patient population differed in many respects from the source population, the area under the receiver operating characteristic curve amounted to .77, a value very much comparable to the one found in the source population. CONCLUSIONS: The nomogram provides a fairly accurate predicted probability for the likelihood of non-SLN metastases in a general population of breast cancer patients at a regional teaching hospital in The Netherlands. This suggests that the nomogram's originally calculated predictive accuracy may be valid for patient populations that differ considerably from the population in which it was developed.
Breast Neoplasms↗
Experience with shared decision making in gynaecological practice: treatment decisions in patients with dysfunctional uterine blood loss.
OBJECTIVE: To study the impact of introducing a blood loss chart as a means to support treatment selection in women with dysfunctional uterine blood loss. STUDY DESIGN: Retrospective chart review, prospective observational study, and decision modelling. RESULTS: Introduction of a blood loss chart resulted in a 50% reduction of re-treatments within 1 year (from 25% to 12.5%). The use of the blood loss chart resulted in a slightly higher expected value and lower costs, which is reflected in a more favourable cost/quality adjusted life year (QALY) ratio. CONCLUSION: The use of a blood loss chart as an aid in treatment selection in women with dysfunctional uterine blood loss is feasible. Although its use requires an extra outpatient visit, the associated extra costs are off-set by its impact on initial treatment selection, and, in particular, on the probability of re-treatment within 1 year of follow-up.
Adult↗
Cost-effectiveness analysis in relation to budgetary constraints and reallocative restrictions.
BACKGROUND: Present cost-effectiveness analyses (CEAs) provide not all information necessary for decision-making. One of the factors that hamper decision-making is the difficulty in reallocating resources to new technologies. In a CEA, the incremental costs and incremental benefits of a new technology are calculated. In this article we focus on the incremental cost side. The underlying assumption in socio-economic evaluation is that resources from the substituted alternatives can be used to finance the new technology. In practice, however, not all resources are becoming available to introduce the alternative. The budgets in health care are rather fixed and shifting from one alternative to another or from one sector to another is often impossible. Even within a budget, the personnel and material resources are usually not entirely usable for the new technology, and sometimes not at all. Therefore, the present CEA outcomes might overestimate the cost-effectiveness in practice, which might influence implementation of a new technology. AIM: To optimise the usefulness of economic evaluation for health care decision-making by correcting the incremental costs of a new technology for the possible limitations in reallocating resources and adjusting budgets in health care. METHODS: Case Research. Literature, data from two completed CEAs and interviews with decision makers in the hospital setting. RESULTS: Case 1: The combined outpatient and home-treatment of psoriasis--In a CEA it was calculated that the new technology lead to much lower cost, given the same effects. The direct costs of this technology comprise personnel, material and capacity costs. Personnel and capacity are inflexible with regard to reallocation, at least in the short term. Considering these reallocative restrictions results show that the cost-savings of the combined treatment are in the short run significantly smaller than in the long run: 694 versus 6.058, respectively. Therefore, the anticipated savings, estimated are not realistic for decision makers with a short time horizon. The short-term savings amount to only 11% of the anticipated savings in the long run. Nevertheless, the combined treatment remains a cost-effective treatment. Analysing the budgetary constraints resulted in the finding that the substitution of the in-hospital treatment by the combined treatment has taken place without negative financial consequences for the hospital. Case 2: The ground bound mobile medical team--Economic arguments to implement the ground bound mobile medical team (MMT) are undecided. With respect to the budgetary constraints we find that the budget for the trauma centre is conditional upon the deployment of the ground bound MMT. Moreover, the cost of the ground bound MMT is a relatively small part of the budget for the trauma centre and therefore no hurdle to implement. CONCLUSIONS: On the basis of these findings we conclude that limitations in reallocating resources and adjusting budgets in health care may hamper the usefulness of economic evaluation for decision-making. Researching the extent of these limitations provides, together with the CEA, better information on which the decision whether a new technology should be implemented and what the expected welfare gains from such an implementation might be can be made. For this a set of checklists is developed.
Budgets↗
Bayes' theorem: a negative example of a RCT on grommets in children with glue ear.
Bayesian inference presupposes that practitioners' belief in the effectiveness of medical intervention is the product of prior belief and recent evidence from studies. Although increasingly used, up to now the posterior belief calculated according to the theorem has not been compared with an empirically measured posterior belief. We conducted a RCT, which was preceded by elicitation of prior beliefs among ENT-surgeons, and which was followed by elicitation of posterior beliefs among ENT-surgeons, 1 year after completion of the trial. We compared the posterior beliefs of ENT-surgeons about the effect of grommets in children with glue ears, as predicted by Bayes' theorem with actual measured posterior beliefs. The distribution of the measured posterior beliefs was not in line with the calculated posterior, but almost identical to the distribution of the measured prior beliefs. The results showed that our trial had little or no impact on the beliefs of the ENT-surgeons, i.e. they did not adjust their belief to the extent that was expected according to Bayes' theorem.
Bayes Theorem↗
Prospective randomized controlled study comparing simple decompression versus anterior subcutaneous transposition for idiopathic neuropathy of the ulnar nerve at the elbow: Part 1.
OBJECTIVE: The main objective of this study was to compare the clinical outcome of participants treated by simple decompression (SD) of the ulnar nerve versus anterior subcutaneous transposition (AST). METHODS: A prospective randomized controlled study was performed. Three hundred forty participants were referred to our institution between March 1999 and July 2002. One hundred fifty-two patients met the inclusion criteria and were randomized into two surgical groups: 75 were assigned to SD, and 77 were assigned to AST. Participants were followed for 1 year after surgery. The main outcome measure was clinical outcome 1 year after surgery. RESULTS: An excellent or good result was obtained in 49 of 75 participants who underwent SD and in 54 of 77 participants undergoing AST. The difference was not statistically significant. However, the complication rate was statistically lower in the SD group (9.6%) compared with the AST group (31.1%) (risk ratio, 0.32; 95% confidence interval, 0.14-0.69). Duration of symptoms, (sub)luxation of the ulnar nerve, and severity of the complaints did not influence outcome. CONCLUSION: Surgery for ulnar neuropathy at the elbow is effective. The outcomes of SD and AST are equivalent, except for the complication rate. Because the intervention is simpler and associated with fewer complications, SD is advised, even in the presence of (sub)luxation.
Adult↗
Simple decompression or anterior subcutaneous transposition for ulnar neuropathy at the elbow: a cost-minimization analysis--Part 2.
OBJECTIVE: A randomized controlled trial was reported recently, in which simple decompression and anterior subcutaneous transposition were compared for treatment of ulnaropathy at the elbow. Clinically, both surgical options seem to be equally effective. The objective of this study is to compare the costs, from a societal standpoint, of simple decompression versus anterior subcutaneous transposition in Euros. METHODS: Published and unpublished data from a randomized controlled trial that compared simple decompression and anterior subcutaneous transposition were used. The investigators tabulated the actual costs incurred for professional fees, use of the operating room, duration of sick leave, reintervention, and treatment of complications directly related to the surgical treatment. RESULTS: The total costs per group and per patient were statistically significantly less for those treated with simple decompression. The total median costs per patient were 1124 Euros for simple decompression and 2730 Euros for anterior subcutaneous transposition. The main difference was in the costs related to sick leave, which is significantly shorter for simple decompression. There also was a statistically significant difference in operation time in favor of simple decompression. A remarkable finding was that paid workers in both treatment groups returned to work much later than unpaid workers. CONCLUSION: Although clinically equally effective, simple decompression was associated with lower cost than anterior subcutaneous transposition for the treatment of ulnar neuropathy at the elbow. Compared with anterior subcutaneous transposition, we recommend simple decompression for the treatment of idiopathic ulnar neuropathy at the elbow.
Absenteeism↗
Policy relevance of Bayesian statistics overestimated?
OBJECTIVES: The observed posterior probability distributions regarding the benefits of surgery for otitis media with effusion (OME) with expected probability distributions, using Bayes' theorem are compared. METHODS: Postal questionnaires were used to assess prior and posterior probability distributions among ear-nose-throat (ENT) surgeons in the Netherlands. RESULTS: In their prior probability estimates, ENT surgeons were quite optimistic with respect to the effectiveness of tube insertion in the treatment of OME. The trial showed no meaningful benefit of tubes on hearing and language development. Posterior probabilities calculated on the basis of prior probability estimates and trial results differed widely from those, elicited empirically 1 year after completion of the trial and dissemination of the results. CONCLUSIONS: ENT surgeons did not adjust their opinion about the benefits of surgical treatment of glue ears to the extent that they should have done according to Bayes' theorem. Users of the results of Bayesian analyses, notably policy-makers, should realize that Bayes' theorem is prescriptive and not necessarily descriptively correct. Health policy decisions should not be based on the untested assumption that health-care professionals use new evidence to adjust their subjective beliefs in a Bayesian manner.
Attitude of Health Personnel↗
Economic evaluation of folate supplementation during methotrexate treatment in rheumatoid arthritis.
OBJECTIVE: To determine cost-effectiveness of folic or folinic acid supplementation in patients with rheumatoid arthritis (RA) who started methotrexate (MTX) treatment. METHODS: An economic evaluation, performed alongside a randomized, double blind, placebo controlled trial with followup of 48 weeks. Patients started MTX with placebo (n = 137), folic acid (n = 133), or folinic acid (n = 141). Outcome measures were drug survival and quality-adjusted life-years (QALY), measured with the EuroQol questionnaire. Both medical and nonmedical costs were analyzed. RESULTS: Drug survival after 48 weeks was 60% for placebo, 81% for folic acid, and 87% for folinic acid. QALY during a 48 week period were 0.55 (95% CI 0.52-0.58) in the placebo group, 0.55 (95% CI 0.52-0.58) in the folic acid group, and 0.58 (95% CI 0.56-0.60) in the folinic acid group. Mean medical costs were 1398 US dollars (placebo), 1409 US dollars (folic acid), and 1776 US dollars (folinic acid). Mean total costs were 3339 US dollars, 3632 US dollars, and 3296 US dollars, respectively. CONCLUSION: In terms of resource deployment, no statistically significant difference was found between the 3 strategies. The preferred strategy consists of folic acid supplementation because of improved drug survival.
Antirheumatic Agents↗
Health care and the principle of fair equality of opportunity: a report from The Netherlands.
In The Netherlands, the public funding of a number of health care services is controversial. What can we learn from this about the moral concerns that underlie these judgements? And, if there is anything to learn, can we use this improved understanding to scrutinise the adequacy of particular decisions concerning the public funding of health care services? In the present paper, I will analyse three cases: corrective surgery, In Vitro Fertilisation and liver transplantation. I will summarise the arguments that have been used to support or to challenge the public funding of these services. I will then assess the merits of Daniels' fair equality of opportunity account of justice in health care. Can this account improve our understanding of the moral concerns underlying our judgements about the public funding of these services? Can it serve to scrutinise the adequacy of particular decisions that are made concerning the public funding of health care services? My answer to both questions will be a qualified yes. Daniels' account can provide guidance, but not because we can deductively infer from it what is right and what is wrong. Instead, I will argue for a more casuistic use of the concept of fair equality of opportunity.
Attitude↗