Medium-term cost analysis of breast reconstructions in a single Dutch centre: a comparison of implants, implants preceded by tissue expansion, LD transpositions and DIEP flaps.

BACKGROUND: Free flap breast reconstruction (BR) is generally believed to be more expensive than implant BR, but costs were previously shown to level out over time due to complications and re-operations. The aim of this study was to assess the economic implications of four BR techniques: silicone prosthesis (SP), implant preceded by tissue expansion (TE/SP), latissimus dorsi transposition with or without implant (LD ± SP) and deep inferior epigastric perforator (DIEP) flap. METHODS: A prospective historic cohort study was performed to evaluate intramural medical costs in 427 patients, who had undergone BR between 2002 and 2009. Short- and medium-term complications were incorporated. In addition, 58 patients, who had recently undergone BR, participated in a questionnaire study to prospectively evaluate extramural medical and non-medical costs. Estimates of mean short- and medium-term costs are presented per patient. RESULTS: Intramural medical costs for BR and short-term complications for unilateral DIEP flaps (€ 12,848) and TE/SP reconstructions (€ 12,400) were significantly higher than those for LD ± SP reconstructions (€ 5804), which, in turn, were more expensive than SP reconstructions (€ 4731). In bilateral cases, costs of TE/SP (€ 12,723) and LD ± SP (€ 10,760) reconstructions were comparable, while DIEP flaps (€ 15,747) were significantly more expensive and SP reconstructions were significantly cheaper (€ 6784). Overall, the medium-term costs for complications and additional operations were not significantly different (€ 3017-€ 4503). Extramural medical costs and non-medical costs were approximately € 9300 per stage, regardless of technique. CONCLUSIONS: Differences in short-term costs between techniques did not level out during follow-up and SP reconstructions remained least expensive. Single-stage SP reconstructions, however, are not suitable for all patients due to high complication rates. Definite implant placement is therefore increasingly preceded by tissue expansion at more comparable costs to autologous BR. Incorporation of non-medical costs into the cost analysis would render two-stage procedures more costly than autologous BR. To achieve the optimal result, careful patient selection is critical. Only in select cases where two options are equally applicable, cost comparison becomes a valid argument for treatment selection.

Screening for colorectal cancer: comparison of perceived test burden of guaiac-based faecal occult blood test, faecal immunochemical test and flexible sigmoidoscopy.

BACKGROUND: Perceived burden of colorectal cancer (CRC) screening is an important determinant of participation in subsequent screening rounds and therefore crucial for the effectiveness of a screening programme. This study determined differences in perceived burden and willingness to return for a second screening round among participants of a randomised population-based trial comparing a guaiac-based faecal occult blood test (gFOBT), a faecal immunochemical test (FIT) and flexible sigmoidoscopy (FS) screening. METHODS: A representative sample of the Dutch population (aged 50-74years) was randomised to be invited for gFOBT, FIT and FS screening. A random sample of participants of each group was asked to complete a questionnaire about test burden and willingness to return for CRC screening. RESULTS: In total 402/481 (84%) gFOBT, 530/659 (80%) FIT and 852/1124 (76%) FS screenees returned the questionnaire. The test was reported as burdensome by 2.5% of gFOBT, 1.4% of FIT and 12.9% of FS screenees (comparing gFOBT versus FIT p=0.05; versus FS p<0.001). In total 94.1% of gFOBT, 94.0% of FIT and 83.8% of FS screenees were willing to attend successive screening rounds (comparing gFOBT versus FIT p=0.84; versus FS p<0.001). Women reported more burden during FS screening than men (18.2% versus 7.7%; p<0.001). CONCLUSIONS: FIT slightly outperforms gFOBT with a lower level of reported discomfort and overall burden. Both FOBTs are better accepted than FS screening. All three tests have a high level of acceptance, which may affect uptake of subsequent screening rounds and should be taken into consideration before implementing a CRC screening programme.

Nurse-led follow-up of patients after oesophageal or gastric cardia cancer surgery: a randomised trial.

Between January 2004 and February 2006, 109 patients after intentionally curative surgery for oesophageal or gastric cardia cancer were randomised to standard follow-up of surgeons at the outpatient clinic (standard follow-up; n=55) or by regular home visits of a specialist nurse (nurse-led follow-up; n=54). Longitudinal data on generic (EuroQuol-5D, European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30) and disease-specific quality of life (EORTC QLQ-OES18), patient satisfaction and costs were collected at baseline and at 6 weeks and 4, 7 and 13 months afterwards. We found largely similar quality-of-life scores in the two follow-up groups over time. At 4 and 7 months, slightly more improvement on the EQ-VAS was noted in the nurse-led compared with the standard follow-up group (P=0.13 and 0.12, respectively). Small differences were also found in patient satisfaction between the two groups (P=0.14), with spouses being more satisfied with nurse-led follow-up (P=0.03). No differences were found in most medical outcomes. However, body weight of patients of the standard follow-up group deteriorated slightly (P=0.04), whereas body weight of patients of the nurse-led follow-up group remained stable. Medical costs were lower in the nurse-led follow-up group (2600 euro vs 3800 euro), however, due to the large variation between patients, this was not statistically significant (P=0.11). A cost effectiveness acceptability curve showed that the probability of being cost effective for costs per one point gain in general quality-of-life exceeded 90 and 75% after 4 and 13 months of follow-up, respectively. Nurse-led follow-up at home does not adversely affect quality of life or satisfaction of patients compared with standard follow-up by clinicians at the outpatient clinic. This type of care is very likely to be more cost effective than physician-led follow-up.

[The 1996 revision of the Dutch cervical cancer screening programme: increased coverage, fewer repeat smears and less opportunistic screening]. / Herziening bevolkingsonderzoek op baarmoederhalskanker 1996: hogere dekkingsgraad, minder herhalingsuitstrijkjes en minder opportunistische screening.

OBJECTIVE: Comparison of the indicators of effectiveness and efficiency of the Dutch national cervical cancerscreening programme in 2003 and 1994, the last year before implementation of important changes in the medical and organisational guidelines. DESIGN: Descriptive. METHOD: Data on all Pap smears made in 1994 and 2003 were retrieved from the Pathologic Anatomical National Automated Archive (PALGA), together with the matching cytological and histological follow-up until April 2004. In order to calculate the 5-year coverage, the number of women that had had a smear taken was placed in the numerator and divided by the number of women that had been invited for the screening programme during those 5 years. RESULTS: The 5-year coverage in the age range 30-64 years increased from 69 in 1994 to 77% in 2003. The percentage of smears resulting in a recommendation for a repeat smear decreased from 10 to 2. The percentage of timely compliance with recommendations for a repeat smear increased from 47 to 86, while that of smears with an immediate referral recommendation remained the same (about go). There was a sharp decrease in screening outside of the target-age range and screening with too short an interval. As a consequence, despite the higher coverage, the total number of smears decreased. CONCLUSION: The changes in the Dutch cervical cancerscreening programme in 1996 with regard to participation, the number of and compliance with recommendations for repeat smears, and screening activity outside of the target group were accompanied by significant improvements in agreement with the goals of the revision. The potential consequences for the effectiveness of the screening programme (reduction of cervical cancer mortality) will become apparent in the years to come.

The burden of upper gastrointestinal endoscopy in patients with Barrett's esophagus.

BACKGROUND AND STUDY AIMS: Patients with Barrett's esophagus are recommended to undergo regular surveillance with upper gastrointestinal endoscopy, an invasive procedure that may cause anxiety, pain, and discomfort. We assessed to what extent patients perceived this procedure as burdensome. PATIENTS AND METHODS: A total of 192 patients with Barrett's esophagus were asked to fill out questionnaires at 1 week and immediately before endoscopy, and at 1 week and 1 month afterwards. Four variables were assessed: (i) pain and discomfort experienced during endoscopy; (ii) symptoms; (iii) psychological burden, i. e., anxiety, depression and distress levels (Hospital Anxiety and Depression scale, Impact of Event Scale); and (iv) perceived risk of developing adenocarcinoma. RESULTS: At least one questionnaire was returned by 180 patients (94 %), 151 completed all four (79 %). Of all patients, only 14 % experienced the endoscopy as painful. However, 59 % reported it to be burdensome. Apart from an increase in throat ache (47 % after endoscopy versus 12 % before), the procedure did not cause physical symptoms. Patients' anxiety, depression, and distress levels were significantly increased in the week before endoscopy compared with the week after. Patients perceiving their risk of developing adenocarcinoma as high reported higher levels of psychological distress and that the procedure was a greater burden. CONCLUSIONS: Upper gastrointestinal endoscopy is burdensome for many patients with Barrett's esophagus and causes moderate distress. Perception of a high risk of adenocarcinoma may increase distress and the burden experienced from the procedure. The benefits of endoscopic surveillance for patients with Barrett's esophagus should be weighed against its drawbacks, including the short-term burden for patients.

Reliability and validity of the Health Outcomes Burn Questionnaire for infants and children in The Netherlands.

The Health Outcomes Burn Questionnaire (HOBQ) is a self-administered questionnaire to monitor outcome after burns in young children. This study aimed to assess feasibility, reliability and validity of the Dutch version of the HOBQ. The HOBQ was adapted into Dutch and tested in a population of children aged 0-4 years with a primary admission to a Dutch burn centre in March 2001-February 2004. Parents of 413 children were sent a questionnaire. To assess validity, a generic outcome instrument was included, the Infant Toddler Quality of Life Questionnaire (ITQOL). The response rate was 50.0% (n=196). Mean self-reported completion time was 16.7 min. The internal consistency of all the HOBQ-scales was good (Cronbach's alpha's>0.69). Test-retest results showed no differences in 7 out of 10 scales. High correlations between HOBQ-scales and conceptually equivalent ITQOL and scales were found in 5 out of 7 comparisons. The majority of the HOBQ-scales (7 out of 10) showed significant differences in the expected direction between children with a long versus short length of stay. Our data support the reliability and validity of the Dutch HOBQ. The HOBQ can be used as a research tool, to monitor functional outcome after burns in young children. Further research in other samples is recommend to fully establish the reliability and validity of the HOBQ.

Reliability and validity of health status measurement by the TAPQOL.

BACKGROUND: In addition to clinical measures in the evaluation of paediatric interventions, health related quality of life (HRQoL) is an important outcome. The TAPQOL (TNO-AZL Preschool children Quality of Life) was developed to measure HRQoL in preschool children. It is a generic instrument consisting of 12 scales that cover the domains physical, social, cognitive, and emotional functioning. AIMS: To evaluate the feasibility, score distribution, internal consistency, test-retest reliability, and discriminative and concurrent validity of the TAPQOL multi-item scales in preschool children, aged 2-48 months. Also to evaluate the feasibility, reliability, and validity separately for infants (2-12 months old) and toddlers (12-48 months old). METHODS: Parents of a random general population sample of 500 preschool children were sent a questionnaire by mail. A random subgroup of 159 parents who participated received a retest after two weeks. RESULTS: The response rate was 83% at the test and 75% at the retest. There were few missing answers. Six scales showed ceiling effects. Nine scales had Cronbach's alphas >0.70. In general, score distributions and Cronbach's alphas were comparable for infants and toddlers. Test-retest showed no significant differences in mean scale scores; two scales had intra-class correlations <0.50. Five scales showed significant differences between children with no conditions versus children with two or more parent reported chronic conditions. CONCLUSION: Results showed that the TAPQOL is a feasible instrument to measure HRQoL and support the reliability and discriminative validity of the majority of its scales for infants as well as toddlers.

Including the quality-of-life effects in the evaluation of prostate cancer screening: expert opinions revisited?

OBJECTIVE: To apply the general empirical framework for estimating utilities in cost-utility analysis (CUA) of population-based prostate cancer screening, including an assessment of empirical health status with a classifying measure (e.g. the EQ-5D) and linking these descriptions to utility estimates using the standard preference-based algorithm, combining them with the appropriate duration into quality-adjusted life years, and sensitivity analysis. MATERIALS AND METHODS: Empirical studies to describe and value the health status effects of prostate cancer screening have been ongoing within the Rotterdam centre of the European Randomised Study on Screening for Prostate Cancer since 1995. The results of these studies, including the screening, the primary treatment phase and advanced disease, will be used in estimating utilities for cost-utility analysis. RESULTS: Estimation of cost-utility of population-based prostate cancer screening with the results of the three empirical health status studies yielded partly counterintuitive results, underestimating the unfavourable health status effects that are inevitably associated with prostate cancer screening. This may be caused by other than health effects of the screening itself ('process effects') and adaptive changes in perception of their situation in patients after curative primary treatment ('response shift'), among other elements. CONCLUSIONS: These results prompted us to reconsider the suitability of the general framework of CUA for screening programmes. Possible directions for solutions are indicated.

Reliability and validity of the child health questionnaire-child form (CHQ-CF87) in a Dutch adolescent population.

UNLABELLED: Feasibility, reliability, and discriminative validity of the cross-culturally adapted Dutch version of the originally US child health questionnaire-child form (CHQ-CF87), an 87-item generic pediatric health-related quality of life instrument, were assessed. The success criterion in this first evaluation was the equivalence of psychometric properties of the adapted and the original CHQ. A total of 466 schoolchildren (9-17 years) were invited to complete the questionnaire in the classroom. Test-retest reliability was measured after 14 days in a subgroup (n = 71). Response was 96%. Four scales had ceiling effects (>50%), as was reported in an Australian study. Cronbach alpha-values were adequate (>0.70), except for 'physical functioning' (0.56). Test-retest correlations, not previously reported, were not statistically significant for two CHQ-scales, whereas average retest scores indicated better health for five scales (p < 0.01). The CHQ scales discriminated significantly (p < 0.01) between children without (n = 281) and children with two or more self-reported chronic diseases (n = 59). This is in correspondence with US and Australian reports. CONCLUSIONS: The current data support application of the Dutch CHQ-CF in predominantly healthy populations, e.g. in school settings. Given the limitations of this study and some less favorable results (score distributions, internal consistency, test-retest reliability), further evaluation of the CHQ-CF is recommended, preferably by analyses of item performance and scale validity in international data sets that include varied clinical subgroups.

Health-related quality of life and cost-effectiveness studies in the European randomised study of screening for prostate cancer and the US Prostate, Lung, Colon and Ovary trial.

Decisions on policies for screening for prostate cancer require that information upon health-related quality of life (HRQL) and cost-effectiveness (CE) be available, as the lead time for some of the cases detected by screening will be very long and detriments in quality of life could have a major impact on the subjects remaining life-span. A framework within which both HRQL and cost-effectiveness of prostate cancer screening can be assessed is presented. Studies of both are ongoing in the European Randomised Study of screening for prostate cancer and the US Prostate, Lung, Colon and Ovary trial. Preliminary information confirms that it is important to study screened subjects and controls, and not to assume that inferences derived from study of prostate cancer outside screening trials can be extrapolated to the trials. However, it will require prolonged study to enable the overall effects on quality of life, and on cost-effectiveness to be determined. Such studies are ongoing for the two trials.

A national burden of disease calculation: Dutch disability-adjusted life-years. Dutch Burden of Disease Group.

OBJECTIVES: This study estimated the burden of disease due to 48 major causes in the Netherlands in 1994 in disability-adjusted life-years (DALYs), using national epidemiologic data and disability weights, and explored associated problems and uncertainties. METHODS: We combined data from Dutch vital statistics, registrations, and surveys with Dutch disability weights to calculate disease-specific health loss in DALYs, which are the sum of years of life lost (YLLs) and years lived with disability (YLDs) weighted for severity. RESULTS: YLLs were primarily lost by cardiovascular diseases and cancers, while YLDs were mostly lost by mental disorders and a range of chronic somatic disorders (such as chronic nonspecific lung disease and diabetes). These 4 diagnostic groups caused approximately equal numbers of DALYs. Sensitivity analysis calls for improving the accuracy of the epidemiologic data in connection with disability weights, especially for mild and frequent diseases. CONCLUSIONS: The DALY approach appeared to be feasible at a national Western European level and produced interpretable results, comparable to results from the Global Burden of Disease Study for the Established Market Economies. Suggestions for improving the methodology and its applicability are presented.

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.

Estimating parametric relationships between health description and health valuation with an application to the EuroQol EQ-5D.

Generic health status measures classify patients into different health states. For example, the EQ-5D descriptive system developed by the EuroQol Group classifies patients into 243 health states. Empirical values for the health states are available for only a selection (mostly 12 to 45) of these health states. Several parametric relationships between the descriptive system and the known values can be formulated to estimate the values for the unrecorded health states. This paper describes several of these modeling exercises in a comprehensible way, using the EQ-5D as an illustration. It is shown that the estimation task does not depend on the meaning of the values, but does depend on the selection of the empirically valued health states and the assumptions about the relationship between these values and the descriptive system.

Translation, validation, and norming of the Dutch language version of the SF-36 Health Survey in community and chronic disease populations.

The primary objectives of this research were to translate, validate, and generate normative data on the SF-36 Health Survey for use among Dutch-speaking residents of the Netherlands. Translation of the SF-36 into Dutch followed the stepwise, iterative procedures developed by the IQOLA Project. Following extensive pilot testing, the SF-36 was administered to: (1) a random sample of adult residents of Amsterdam (n = 4172); (2) a random, nationwide sample of adults (n = 1742); (3) a sample of migraine sufferers (n = 423); and (4) a sample of cancer patients undergoing active anti-neoplastic treatment (n = 485). Data quality across the four studies was consistently high. The rates of missing data ranged from 1% to 5% at the item level, and from 1.2% to 2.6% at the scale level. Multitrait scaling analysis confirmed the hypothesized scale structure of the SF-36 and associated scale scoring in all four samples. Cronbach's alpha coefficients surpassed the 0.70 criterion for group comparisons in all but one case (the Social Functioning scale in the cancer sample), with a mean alpha coefficient across all scales and samples of 0.84. Known-group comparisons yielded consistent support for the validity of the SF-36. In the two community samples, statistically significant differences in SF-36 mean scale scores were observed as a function of age, gender, and the prevalence of chronic health conditions. In the migraine and cancer samples, mean SF-36 scale scores varied significantly as a function of various indicators of disease severity. The SF-36 profiles for the two community samples were highly similar. The cancer sample yielded the lowest SF-36 scores, with the migraine sample holding an intermediate position. On-going studies will generate data on the responsiveness of the SF-36 to within-group changes in health over time. Efforts are underway to translate and validate the questionnaire for use among ethnic minority groups in the Netherlands.

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.

Sacral rhizotomies and electrical bladder stimulation in spinal cord injury. 2. Cost-effectiveness and quality of life analysis. Dutch Study Group on Sacral Anterior Root Stimulation.

OBJECTIVES: To present a cost-effectiveness analysis of sacral rhizotomies and electrical bladder stimulation compared with conventional care of neurogenic bladder dysfunction in patients with spinal cord injury. METHODS: During a 3-year inclusion period, data on costs and quality of life before the intervention were collected to describe conventional care. Data on the pre-implantation period, the implantation and a follow-up period of 2 years were collected following a strict protocol simultaneous with medical and urodynamic data and were used to calculate the costs and effects on quality of life of the implantation of the stimulator. RESULTS: Between June 1991 and June 1994, 52 patients with complete cervical or thoracic spinal cord lesions underwent sacral posterior rhizotomies and implantation of a Finetech-Brindley sacral anterior root stimulator. Although the initial costs of sacral anterior root stimulation are high, they are earned back in this series in about 8 years after the implantation. General indicators of the quality of life show no significant changes after the implantation. Factors related to psychological well-being and the patients' satisfaction with the emptying of the bladder increased significantly whereas the experienced problems of micturition and incontinence all decreased significantly. CONCLUSION: Sacral rhizotomies and electrical bladder stimulation make a cost-effective method of treatment of lower urinary tract dysfunction in patients with spinal cord injury. Considerable savings on health care costs are possible in the long run with simultaneous positive effects on aspects of health status.

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.

Labor and health status in economic evaluation of health care. The Health and Labor Questionnaire.

A health care program may influence both costs and health effects. We developed the Health and Labor Questionnaire (HLQ), which consists of four modules, to collect data on absence from work, reduced productivity, unpaid labor production, and labor-related problems. We applied the HLQ in several studies, and the results are encouraging.

Societal perspective on the burden of migraine in The Netherlands.

This study presents a comprehensive overview of the societal burden of migraine in The Netherlands. We assessed the direct and indirect costs of this disease, and the health status of patients with migraine. We developed the 'illness and labour' (I&L) questionnaire to collect data on the effect of illness on labour performance. 846 migraine patients and 834 controls were selected from the general population. Participants completed an I&L questionnaire as well as generic health status questionnaires. The direct costs of migraine amounted to 134 million Netherlands guilders (NLG) [$US1 = NLG1.68, October 1994]. Conservative calculations of the costs of absence from work and reduced productivity at work were NLG264 and NLG277 million per year, respectively. Our study did not indicate that migraine caused household productivity losses. The baseline estimate of the total societal costs of migraine in The Netherlands was NLG675 million per year. The assessment of health status showed considerable impairment of psychological and social functioning in migraine patients.

Test-retest reliability of health state valuations collected with the EuroQol questionnaire.

This study is a contribution by the Dutch participants to the research programme of the EuroQol Group. This collaborative group of researchers engaged in outcome measurement is working towards the development of a standardized, non-disease-specific instrument for describing and particularly valuing health-related quality of life. The present article analyses the test-retest reliability of the valuations collected with the EuroQol questionnaire in a population survey (n = 208). The choice of the appropriate method for test-retest analysis is discussed and the results of several approaches with the EuroQol data are shown. Generalizability Theory is proposed as the most suitable method. This method is the most comprehensive, giving distinct information about the relative contributions of different sources of variance. The EuroQol valuations appear to have good test-retest reliability.