Biomedical subjects

W B van den Hout

Publications and source records attributed to W B van den Hout.

9 recordsLinked to original sources

PubMed2005

Long-term followup of health status in patients with severe rheumatoid arthritis after high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation.

OBJECTIVE: High-dose chemotherapy (HDC) followed by autologous hematopoietic stem cell transplantation (HSCT) is a new treatment for patients with severe, refractory rheumatoid arthritis (RA). The present study was undertaken to assess the health status of patients with severe RA over a long-term followup period after treatment with HDC + HSCT. METHODS: Health status and utility scores were assessed in 8 patients before and after treatment with HDC + HSCT. Patients were followed up for 5 years posttransplantation. Health status was assessed by the Health Assessment Questionnaire (HAQ), the RAND-36 version of the Short Form 36 (SF-36) health survey, and the Arthritis Impact Measurement Scales (AIMS). Utility scores were calculated using the EuroQol (EQ-5D) questionnaire and the SF-36-derived utility index (called the SF-6D), from which quality-adjusted life years (QALYs) were derived. RESULTS: Most measures of health status improved compared with baseline in the first 2 years posttransplantation, notably HAQ and AIMS scores and scores on the functional status, general health, and health change summary scales of the RAND-36 version of the SF-36. Utility scores derived from the EQ-5D questionnaire and the SF-6D also increased significantly after transplantation. This was reflected in the 0.28 QALYs gained compared with baseline. For a putative 50-year-old RA patient with a life expectancy of 20 years, a threshold analysis revealed that HDC + HSCT yielded more QALYs than conventional therapy when treatment-related mortality (TRM) was <2.8%. CONCLUSION: HDC + HSCT temporarily increased the functionality and health status of patients with severe, refractory RA. With a reported TRM of 1.3%, HDC + HSCT can be considered a realistic treatment option for patients with severe RA.

Adult↗

PubMed2004

Looking for caries...? Teachers evaluate a program to improve caries diagnosis from radiographs.

We developed a computer-assisted learning (CAL) program to improve student caries diagnosis from bitewing radiographs. In order to decide on its appropriateness, dental teachers independently evaluated the program before it was introduced. Our objective was to describe an evaluation by the teachers of the CAL diagnostic module and to compare the diagnostic performance with the evaluation score of the program. Key dental teachers involved in teaching clinical caries diagnosis and epidemiology (n = 22) viewed the CAL program. They evaluated aspects of the program by scoring 10 criteria on a visual analogue scale. Measures of the teachers' initial diagnostic accuracy assessed during use of the program were: sensitivity and specificity for the presence of dentine caries. Using Pearson's correlation coefficients, these measures of the teachers' diagnostic accuracy were compared separately with their evaluation score of one aspect of the program: the overall functionality of the program for a 2nd-year dental student. The teachers' mean sensitivity for dentine caries diagnosis was 76.5% (median 77.8%; SD 15.4%) and the mean specificity was 93.7% (median 94.2%; SD 3.9%). The teachers gave the program a mean overall functionality score of 68% (median 75.1%; SD 21%). Dentists with a lower sensitivity (P = 0.065) for dentine caries tended to give the CAL program a higher overall functionality score than the other teachers. The CAL program was valued as generally useful. It tended to be more highly valued by the dentists with initially lower scores for diagnostic accuracy.

Computer-Assisted Instruction↗

PubMed2003

Cost effectiveness and cost utility analysis of multidisciplinary care in patients with rheumatoid arthritis: a randomised comparison of clinical nurse specialist care, inpatient team care, and day patient team care.

OBJECTIVE: To assess the relative cost effectiveness of clinical nurse specialist care, inpatient team care, and day patient team care. METHODS: Incremental cost effectiveness analysis and cost utility analysis, alongside a prospective randomised controlled trial with two year follow up. Included were patients with rheumatoid arthritis (RA) with increasing difficulty in performing activities of daily living over the previous six weeks. Quality of life and utility were assessed by the Rheumatoid Arthritis Quality of Life questionnaire, the Short Form-6D, a transformed rating scale, and the time tradeoff. A cost-price analysis was conducted to estimate the costs of inpatient and day patient hospitalisations. Other healthcare and non-healthcare costs were estimated from cost questionnaires. RESULTS: 210 patients with RA (75% female, median age 59 years) were included. Aggregated over the two year follow up period, no significant differences were found on the quality of life and utility instruments. The costs of the initial treatment were estimated at euro 200 for clinical nurse specialist care, euro 5000 for inpatient team care, and euro 4100 for day patient team care. Other healthcare costs and non-healthcare costs were not significantly different. The total societal costs did not differ significantly between inpatients and day patients, but were significantly lower for the clinical nurse specialist patients by at least euro 5400. CONCLUSIONS: Compared with inpatient and day patient team care, clinical nurse specialist care was shown to provide equivalent quality of life and utility, at lower costs. Therefore, for patients with health conditions that allow for any of the three types of care, the preferred treatment from a health-economic perspective is the care provided by the clinical nurse specialist.

Activities of Daily Living↗

PubMed2003

Preferences for oral health states: effect on prescribing periapical radiographs.

OBJECTIVES: To elicit preferences for the outcomes of radiographic endodontic diagnosis and subsequent therapy, and to test for differences in these preferences between three types of dental specialists. METHODS: Using the "standard gamble" method, dentists involved in teaching oral diagnosis (n=26) were asked to rank on a scale of 0.0-1.0 their preferences (utilities) for four treatment outcomes, "composite filling in vital tooth", "composite restoration and root filled", "root filled and post crown" and "extraction and bridge", from a previously analysed diagnostic testing and therapeutic strategy for managing damaged anterior teeth. Respondents consisted of oral radiologists (n=9), specialized treatment planners (n=11) and specialist endodontists (n=6). Using the derived utilities, a decision analysis was subsequently carried out on the expected health value of taking periapical radiographs of patients with otherwise symptomless fractured incisors. RESULTS: "Composite restoration and root filled" (mean utility 0.83, SD 0.15) was the option preferred above that of "root filled and post crown" (mean utility 0.77, SD 0.16) by the entire sample of oral diagnosticians (P=0.007). Radiologists and endodontists had higher utilities for "composite restoration and root filled" than treatment planners. According to the decision analysis, for the preferred option of "composite restoration and root filled", taking a radiograph was the best strategy only when the prevalence of pathology exceeds 10%, 12% and 50% for radiologists, endodontists and treatment planners, respectively. CONCLUSIONS: The expected utility of using radiographs as a diagnostic test varies among groups of dental specialists. We conclude that variation in utilities among dentists could in part explain variation in the diagnostic use of dental radiographs.

Adolescent↗

PubMed2003

Randomized controlled trial of a computer-assisted learning program to improve caries detection from bitewing radiographs.

OBJECTIVES: To investigate whether using a computer-assisted learning (CAL) calibration program improves the accuracy of dental students in caries detection from bitewing radiographs. METHODS: Dental students were assigned to an experimental (n=33) and control (n=34) group using a randomized block design. The experimental group used the CAL program with feedback to calibrate themselves against experts in radiographic caries detection and a histological gold standard of the actual clinical condition. Feedback was provided visually of the actual tooth surface condition and in the form of graphics showing diagnostic accuracy performance measures. Performance was tested before the program (for the control group) and after the program (for the experimental group) by assessing surfaces (n=56) from a new independent digital test set of evaluation radiographs for the presence, histologically, of dentine caries (n=23). The summary receiver operating characteristic (SROC) method for summarizing true positive ratio (TPR) (sensitivity) and false positive ratio (FPR) (1-specificity) was used to analyse the dichotomous data. Differences between the control and experimental groups were tested for (a) the area under the SROC curve (A(z)) and (b) the TPR, FPR and diagnostic odds ratio (DOR) using the Mann-Whitney test (P<0.05). RESULTS: The mean TPR for dentine caries detection was 76.3% (SD 13.0%) for the experimental group and 66.9% (SD 14.8%) for the control group (P=0.005). Mean FPRs were similar (experimental 28.1% and control 28.7%; P>0.5). The area under the SROC curve A(z) was 0.832 for the experimental group and 0.773 for the control group (P=0.002). The mean DOR for dentine caries in the experimental group (12.4) was better than that in the control group (8.8) (P=0.003). CONCLUSIONS: The CAL program does improve diagnostic performance. Improving the cognitive feedback provided by the program should be considered before implementation.

Area Under Curve↗

PubMed2002

Cost-effectiveness analysis of colorectal cancer treatments.

A concise overview is provided of the methodology of cost-effectiveness analyses, followed by a survey of published CEAs of colorectal cancer treatments. To gain credibility, the methodology applied in CEAs must be further improved. Costs are rarely estimated from the societal perspective, and little is known about how colorectal patients value their treatment and health.

Chemotherapy, Adjuvant↗

PubMed2002

Comparing the accuracy of Dutch dentists and dental students in the radiographic diagnosis of dentinal caries.

OBJECTIVES: To compare the diagnostic accuracy of dental students using bitewing radiographs for the diagnosis of dentinal caries with that of general dental practitioners and to establish a bench mark for testing for improvement in diagnostic performance. METHODS: Fourth year dental students (n=259) viewed bitewing radiographs of 105 proximal tooth surfaces. According to a micro-radiography "gold standard" 45 surfaces had dentine caries. The students were asked to diagnose presence and absence of dentine caries from which, under supervision, they calculated their sensitivity (TPR) and false positive rate (FPR). The students binary diagnostic data was compared with the historical data from a random sample of Dutch dentists (n=273). The Summary Receiver Operating Characteristic (SROC) curve method was used to analyse the data. The two groups were tested for differences in (a) diagnostic odds ratio and (b) the area under the SROC curve. RESULTS: The students mean TPR for dentine caries diagnosis was 67.2% (s.d. 11.8%) and the FPR was 8.3% (s.d. 8.4%). The corresponding values for dentists were: TPR 54.0% (s.d. 14.1%) and FPR 3.1% (s.d. 4.5%). Significantly more dentists (85%) than students (72%, P<0.001) had a diagnostic odds ratio > or =21. The area under the SROC curve (Az) was 0.8194 for students and 0.8140 for dentists (P=0.70). CONCLUSIONS: In our study (i) the students had a higher TPR but also a higher FPR than the dental practitioners, (ii) their overall performance (Az) was similar but (iii) for a clinically relevant population the dental practitioners would out-perform the students in diagnostic performance.

Benchmarking↗

PubMed1999

International differences in health care costs in Europe and the United States: Do these affect the cost-effectiveness of diagnostic strategies for pulmonary embolism?

The aim of this study was to assess whether potential differences in costs for diagnostic procedures and treatment of pulmonary embolism (PE) among European and U. S. hospitals alter the optimal cost-effective diagnostic strategy for PE. A standardized questionnaire was used to obtain cost data for the diagnosis and treatment of PE in participating European and U. S. hospitals. Costs for diagnostic tests and treatment of PE were then calculated in a standardized manner for all participating hospitals, from the hospital perspective. Costs were used in an existing cost-effectiveness analysis (CEA) model to determine the most cost-effective diagnostic strategy in participating hospitals. There were considerable differences in costs for diagnostic and therapeutic procedures for PE among the participating centers. These differences, however, did not affect the most cost-effective strategy based on incremental cost-effectiveness. In all hospitals the most cost-effective strategy appeared to be ultrasound followed by helical CT. International differences in cost of diagnostic and therapeutic procedures certainly exist and should be considered before applying a published CEA. Nevertheless, despite these cost differences, the diagnostic strategy for PE of ultrasound followed by helical CT appears most cost-effective.

Angiography↗

PubMed1999

The effect of a single fraction compared to multiple fractions on painful bone metastases: a global analysis of the Dutch Bone Metastasis Study.

PURPOSE: To answer the question whether a single fraction of radiotherapy that is considered more convenient to the patient is as effective as a dose of multiple fractions for palliation of painful bone metastases. PATIENTS: 1171 patients were randomised to receive either 8 Gy x 1 (n = 585) or 4 Gy x 6 (n = 586). The primary tumour was in the breast in 39% of the patients, in the prostate in 23%, in the lung in 25% and in other locations in 13%. Bone metastases were located in the spine (30%), pelvis (36%), femur (10%), ribs (8%), humerus (6%) and other sites (10%). METHOD: Questionnaires were mailed to collect information on pain, analgesics consumption, quality of life and side effects during treatment. The main endpoint was pain measured on a pain scale from 0 (no pain at all) to 10 (worst imaginable pain). Costs per treatment schedule were estimated. RESULTS: On average, patients participated in the study for 4 months. Median survival was 7 months. Response was defined as a decrease of at least two points as compared to the initial pain score. The difference in response between the two treatment groups proved not significant and stayed well within the margin of 10%. Overall, 71% experienced a response at some time during the first year. An analysis of repeated measures confirmed that the two treatment schedules were equivalent in terms of palliation. With regard to pain medication, quality of life and side effects no differences between the two treatment groups were found. The total number of retreatments was 188 (16%). This number was 147 (25%) in the 8 Gy x 1 irradiation group and 41 (7%) in the 4 Gy x 6 group. It was shown that the level of pain was an important reason to retreat. There were also indications that doctors were more willing to retreat patients in the single fraction group because time to retreatment was substantially shorter in this group and the preceding pain score was lower. Unexpectedly, more pathological fractures were observed in the single fraction group, but the absolute percentage was low. In a cost-analysis, the costs of the 4 Gy x 6 and the 8 Gy x 1 treatment schedules were calculated at 2305 and 1734 Euro respectively. Including the costs of retreatment reduced this 25% cost difference to only 8%. The saving of radiotherapy capacity, however, was considered the major economic advantage of the single dose schedule. CONCLUSION: The global analysis of the Dutch study indicates the equality of a single fraction as compared to a 6 fraction treatment in patients with painful bone metastases provided that 4 times more retreatments are accepted in the single dose group. This equality is also shown in long term survivors. A more detailed analysis of the study is in progress.

Adult↗