The Erectile Function Visual Analog Scale (EF-VAS): a disease-specific utility instrument for the assessment of erectile function.

UNLABELLED: This article presents the responsiveness results of the Erectile Function Visual Analog Scale (EF-VAS) and reports, for the first time, utilities associated with erectile dysfunction (ED), as calculated by a disease-specific utility assessment. The EF-VAS is a new quality of life (QoL) instrument specific to ED that combines the strengths of the disease-specific approach to measuring QoL (greater disease relevance and responsiveness, with relevance to clinicians and patients) with those of preference-based assessments (generalizability and relevance to decision makers). The EF-VAS has demonstrated feasibility, reliability, and validity as reported in a recent publication. METHODS: Standard instrument development methodology was utilized and the finalized content was integrated into a preference based scoring instrument comprised of two visual analogue scales (VAS). The EF-VAS was implemented in a clinical trial and data from the trial was subjected to validation analysis. Three methods were used to evaluate the responsiveness of the EF-VAS: Spearman correlations, effect size and standardized response means. VAS scores were converted to von Neumann-Morgenstern (vNM) utilities through a conversion curve. RESULTS: The EF-VAS was established to be responsive to changes in disease state within and between patients with ED. The EF-VAS allowed the calculation of vNM utility values and a significant increase in utility was observed in the sildenafil group compared to placebo at study end. CONCLUSION: The EF-VAS represents an important advance in the understanding of the impact of ED on patients' QoL and in providing a mechanism to allow the quantification of the health status that patients associate with ED. Based on its responsiveness, the EF-VAS will provide an important clinical tool to assess and contribute to the understanding of the impact of treatment for ED. The EF-VAS represents a major advance in the science of health-related quality of life (HRQol) assessment, as it is the first validated ED-specific utility assessment reported in the literature.

Effectiveness and safety of repeat courses of hylan G-F 20 in patients with knee osteoarthritis.

OBJECTIVE: To compare the effectiveness and safety of repeat treatment with hylan G-F 20 based on data from a randomized, controlled trial [Raynauld JP, Torrance GW, Band PA, Goldsmith CH, Tugwell P, Walker V, et al. A prospective, randomized, pragmatic, health outcomes trial evaluating the incorporation of hylan G-F 20 into the treatment paradigm for patients with knee osteoarthritis (Part 1 of 2): clinical results. Osteoarthritis Cartilage 2002;10:506-17]. The hypotheses tested were whether the single-course and repeat-course subgroups would be superior to appropriate care and not different from each other. METHOD: A total of 255 patients with knee osteoarthritis were randomized to "appropriate care with hylan G-F 20" or "appropriate care without hylan G-F 20". The hylan G-F 20 group was partitioned into two subgroups: (1) patients who received a single course of hylan G-F 20; and (2) patients who received two or more courses of hylan G-F 20. RESULTS: For the primary effectiveness measure, change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score as a percent of baseline, the single-course subgroup improved by 41%, the repeat-course subgroup by 35%, and the appropriate care group by 14%. Both subgroups improved significantly more than the appropriate care group (P<0.05), and were not statistically significantly different from each other (70% power to detect a 20% difference). Secondary effectiveness measures showed similar results. In the repeat-course subgroup, no statistically significant differences were found in the number of local adverse events, the number of patients with local adverse events, or arthrocentesis rates between the first and repeat courses of treatment. CONCLUSIONS: Although the study was neither designed nor powered to examine repeat treatment, this a posteriori analysis provides support for a favorable effectiveness and safety profile of hylan G-F 20 in repeat course patients.

Evaluation of WOMAC 20, 50, 70 response criteria in patients treated with hylan G-F 20 for knee osteoarthritis.

OBJECTIVE: A secondary analysis of a previously conducted one year randomised controlled trial to evaluate the capacity of responder criteria based on the WOMAC index to detect between treatment group differences. METHODS: 255 patients with knee osteoarthritis were randomised to "appropriate care with hylan G-F 20" (AC+H) or "appropriate care without hylan G-F 20" (AC). In the original analysis, two definitions of patient response from baseline to month 12 were used: (1) at least a 20% reduction in WOMAC pain score (WOMAC 20P); (2) at least a 20% reduction in WOMAC pain score and at least a 20% reduction in either WOMAC function or stiffness score (WOMAC 20PFS). For this analysis, a responder was identified using 50% and 70% minimum clinically important response levels to investigate how increasing response affects the ability to detect treatment group differences. RESULTS: The hylan G-F 20 group had numerically more responders using all patient responder criteria. Increasing the response level from 20% to 50% detected similar differences between treatment groups (25% to 29%). Increasing the response level to 70% reduced the differences between treatment groups (11% to 12%) to a point where the differences were not significant after Bonferroni adjustment. CONCLUSIONS: These results provide evidence for incorporating response levels (WOMAC 50) in clinical trials. While differences at the highest threshold (WOMAC 70) were not statistically detectable, an appropriately powered study may be capable of detecting differences even at this very high level of improvement.

Development and initial validation of a new preference-based disease-specific health-related quality of life instrument for erectile function.

UNLABELLED: Health-related quality of life instruments may be generic or specific. In general, only generic instruments use preference-based scoring. We report on a novel approach to combine in one instrument the strengths of the specific approach, greater disease relevance and responsiveness, with those of preference-based scoring, generalizability through utilities. OBJECTIVES: The primary objective was to develop a self-administered, preference-based instrument capable of measuring utilities in the disease-specific context of erectile dysfunction (ED). METHODS: Content derivation/validation began with a literature review. Eight attributes (domains) were selected to provide clinical experts structure for focus group discussion. Four levels describing a continuum of dysfunction-function were defined for each domain. Each domain, including functional levels, was reviewed and modified until consensus was achieved regarding content. This content was then integrated into a preference based scoring instrument using two visual analogue scales (VAS) with which patients rated three 'marker' health states (representing mild, moderate and severe ED), their self-state and a previously validated external marker state. The instrument was pilot tested, and implemented in a clinical trial. Initial validation analyses have been performed. RESULTS: A self-administered, preference-based, VAS instrument was developed for use in the ED population, and the instrument was feasible to complete, was reliable beyond the threshold of acceptability established a priori and demonstrated good validity. Evidence of these properties accumulates over time and this study begins that process with this instrument. Responsiveness is being assessed in the context of a clinical trial.

Improvement in health utility among patients with rheumatoid arthritis treated with adalimumab (a human anti-TNF monoclonal antibody) plus methotrexate.

OBJECTIVES: To compare health-related quality of life (HRQoL), as measured by health utility, in patients with rheumatoid arthritis (RA) treated with adalimumab (a human anti-tumour necrosis factor (anti-TNF) monoclonal antibody) plus methotrexate or placebo plus methotrexate. METHODS: HRQoL data were obtained in two randomized, double-blind, placebo-controlled, multidose clinical trials conducted in the United States and Canada. The Health Utilities Index Mark 3 (HUI3) was administered in both studies at baseline, at the end of the study and at two time points in between. Patients' HUI3 scores were compared with population norm scores. Change in HUI3 was defined as the end-of-study score minus the baseline score. Utility gained throughout the study was measured by area under the utility curve and expressed as quality-adjusted life years (QALYs). Statistical testing adjusted for confounders and used the Dunnett test to account for multiple comparisons. RESULTS: Patients' utility scores at baseline were low (range of treatment group means 0.38-0.44) compared with population norms (0.88). HUI3 mean changes from baseline scores for adalimumab-treated patients were 0.22 and 0.21 in the two trials, whereas placebo patients' changes were 0.04 and 0.07. The rate of QALYs gained per year in the treatment group compared with the placebo group were 0.145 in the ARMADA trial and 0.104 in the DE019 trial. All gains were clinically important and statistically significant. CONCLUSIONS: Treatment with adalimumab plus methotrexate provides clinically important and statistically significant improvements in HRQoL as measured by health utility in patients with RA. This translates into measurable and important gains in QALYs.

A prospective, randomized, pragmatic, health outcomes trial evaluating the incorporation of hylan G-F 20 into the treatment paradigm for patients with knee osteoarthritis (Part 1 of 2): clinical results.

OBJECTIVE: First, to assess the clinical effectiveness of hylan G-F 20 in an appropriate care treatment regimen (as defined by the American College of Rheumatology (ACR) 1995 guidelines) as measured by validated disease-specific outcomes and health-related quality of life endpoints for patients with osteoarthritis (OA) of the knee. Second, to utilize the measures of effectiveness and costs in an economic evaluation (see accompanying manuscript). DESIGN: A total of 255 patients with OA of the knee were enrolled by rheumatologists or orthopedic surgeons into a prospective, randomized, open-label, 1-year, multi-centred trial, conducted in Canada. Patients were randomized to 'Appropriate care with hylan G-F 20' (AC+H) or 'Appropriate care without hylan G-F 20' (AC). Data were collected at clinic visits (baseline, 12 months) and by telephone (1, 2, 4, 6, 8, 10, and 12 months). RESULTS: The AC+H group was superior to the AC group for all primary (% reduction in mean Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale: 38% vs 13%,P =0.0001) and secondary effectiveness outcome measures. These differences were all statistically significant and exceeded the 20% difference between groups set a priori by the investigators as the minimum clinically important difference. Health-related quality of life improvements in the AC+H group were statistically superior for the WOMAC pain, stiffness and physical function (all P< 0.0001), the SF-36 aggregate physical component (P< 0.0001) and the Health Utilities Index Mark 3 (HUI3) overall health utility score (P< 0.0001). Safety (adverse events and patient global assessments of side effects) differences favoured the AC+H group. CONCLUSION: The data presented here indicate that the provision to patients with knee OA of viscosupplementation with hylan G-F 20 within an appropriate care treatment regimen provides benefits in the knee, overall health and health related quality of life at reduced levels of co-therapy and systemic adverse reactions.

A prospective, randomized, pragmatic, health outcomes trial evaluating the incorporation of hylan G-F 20 into the treatment paradigm for patients with knee osteoarthritis (Part 2 of 2): economic results.

OBJECTIVE: Viscosupplementation with hylan G-F 20 has recently become registered for treatment of patients with osteoarthritis (OA) of the knee in most parts of the world. The cost effectiveness and cost utility of this new therapeutic modality were determined as part of a Canadian prospective, randomized, 1-year, open-label, multicentered trial. DESIGN: A total of 255 patients were randomized to 'Appropriate care with hylan G-F 20' (AC+H) or 'Appropriate care without hylan G-F 20' (AC). Costs (1999 Canadian dollars) were collected from the societal viewpoint and included all costs related to OA of the knee and OA in all joints. Patients completed a number of outcomes questionnaires including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Health Utilities Index Mark 3 (HUI3). Data were collected at clinic visits (baseline, 12 months) and by telephone (1, 2, 4, 6, 8, 10, and 12 months). RESULTS: The AC+H group over the year had higher costs ($2125-$1415=$710, P< 0.05), more patients improved (69%-40%=29%,P =0.0001), greater increases in HUI3 (0.13-0.03=0.10, P< 0.0001) and increased quality-adjusted life years (QALYs) (0.071, P< 0.05). The incremental cost-effectiveness ratio was $2505/patient improved. The incremental cost-utility ratio was $10000/QALY gained. Sensitivity analyses and a second cost perspective gave similar results. CONCLUSION: The cost-utility ratio is below the suggested Canadian adoption threshold. The results provide strong evidence for adoption of treatment with hylan G-F 20 in the patients and settings studied in the trial.

The Health Utilities Index (HUI) system for assessing health-related quality of life in clinical studies.

This paper reviews the Health Utilities Index (HUI) systems as means to describe health status and obtain utility scores reflecting health-related quality of life (HRQoL). The HUI Mark 2 (HUI2) and Mark 3 (HUI3) classification and scoring systems are described. The methods used to estimate multiattribute utility functions for HUI2 and HUI3 are reviewed. The use of HUI in clinical studies for a wide variety of conditions in a large number of countries is illustrated. HUI provides a comprehensive description of the health status of subjects in clinical studies. HUI has been shown to be a reliable, responsive and valid measure in a wide variety of clinical studies. Utility scores provide an overall assessment of the HRQoL of patients. Utility scores are also useful in cost-utility analyses and related studies. General population norm data are available. The widespread use of HUI facilitates the interpretation of results and permits comparisons. HUI is a useful tool for assessing health status and HRQoL in clinical studies.

Visual analog scales: do they have a role in the measurement of preferences for health states?

Visual analog scales (VASs) have long been used as a method of measuring preferences for health outcomes. They are easy and inexpensive to implement, can be administered quickly, and lend themselves to self-completion. Over time, however, disturbing questions have emerged concerning the validity of the VAS approach. This article reviews briefly the history, theory, practice, problems, and advantages of VASs; presents some suggestions to improve the validity of VASs; and recommends a limited but useful role for VASs in the process of measuring preferences for health states.

What should be reported in a methods section on utility assessment?

BACKGROUND: The measurement of utilities, or preferences, for health states may be affected by the technique used. Unfortunately, in papers reporting utilities, it is often difficult to infer how the utility measurement was carried out. PURPOSE: To present a list of components that, when described, provide sufficient detail of the utility assessment. METHODS: An initial list was prepared by one of the authors. A panel of 8 experts was formed to add additional components. The components were drawn from 6 clusters that focus on the design of the study, the administration procedure, the health state descriptions, the description of the utility assessment method, the description of the indifference procedure, and the use of visual aids or software programs. The list was updated and redistributed among a total of 14 experts, and the components were judged for their importance of being mentioned in a Methods section. RESULTS: More than 40 components were generated. Ten components were identified as necessary to include even in an article not focusing on utility measurement: how utility questions were administered, how health states were described, which utility assessment method(s) was used, the response and completion rates, specification of the duration of the health states, which software program (if any) was used, the description of the worst health state (lower anchor of the scale), whether a matching or choice indifference search procedure was used, when the assessment was conducted relative to treatment, and which (if any) visual aids were used. The interjudge reliability was satisfactory (Cronbach's alpha = 0.85). DISCUSSION: The list of components important for utility papers may be used in various ways, for instance, as a checklist while writing, reviewing, or reading a Methods section or while designing experiments. Guidelines are provided for a few components.

Cost-effectiveness of Apligraf in the treatment of venous leg ulcers.

Venous ulcers are the most common chronic wounds of the lower leg. Skin substitutes recently have been introduced to stimulate nonhealing wounds. To conduct an incremental cost-effectiveness analysis, a model was developed to compare the four-layer bandage system, with and without one application of skin substitute, for the outpatient treatment of venous leg ulcers. The model estimated the costs and consequences of treatment with and without the skin substitute application. Two analytic horizons were explored: 3 months and 6 months. Determined by seven physicians, data and assumptions for the 3-month model were based on information from a clinical trial, published studies, and clinical experience. Data for the 6-month model were extrapolated from the shorter model. The model results indicate that over 3 months, the use of the skin substitute provided a benefit of 22 ulcer days averted per patient at an incremental cost of $304 (societal). The incremental cost-effectiveness ratio was $14 per ulcer day averted. Over 6 months, the incremental cost-effectiveness ratio was less than $5 per ulcer-day averted. The skin substitute plus a four-layer bandage was more costly and more effective than the four-layer bandage alone. The skin substitute is increasingly cost-effective over a longer analytic horizon and in a subgroup of patients with ulcers of long duration (greater than 1-year duration at baseline). The results come from a model that is based on a series of estimates and assumptions, and accordingly, confirmation of this finding in a prospective study is encouraged.

Cost-utility analysis in depression: the McSad utility measure for depression health states.

Cost-utility analysis, used increasingly over the past decade to analyze costs and effects in treating physical diseases, has received little attention in psychiatry. This article briefly introduces the concepts and methods of utility measurement and illustrates it using depression as an example. The authors describe the McSad health state classification system for depression, a direct utility measure for depression, and report results of an application of McSad among 105 patients who had a recent history of depression. Utility measures express patient preferences for specific health states on a scale ranging from 0, representing death, to 1, representing perfect health. These scores provide the weights used to calculate the number of quality-adjusted life-years gained by an intervention or service. McSad allows a patient's depression health state to be classified according to level of functioning in six dimensions of depression and to be compared with other hypothetical depression health states in order to produce utility scores indicating the patient's relative preferences.

Development and testing of a utility measure for major, unipolar depression (McSad).

OBJECTIVE: To develop and test a direct utility measure (McSad) for major, unipolar depression. METHODS: A depression specific, multi-attribute health state classification system was created; clinical validity was evaluated by experts using specially designed structured exercises; a cross-sectional survey was conducted to obtain directly measured utilities for depression health states. SETTING: Tertiary care, university medical centre. PARTICIPANTS: Three psychiatrists, 3 psychiatric nurses and 3 social workers assessed depression health state clinical validity. Survey participants were referred by psychiatrists and consisted of 105 outpatients, currently in remission with at least one episode of major, unipolar depression in the past two years. SURVEY RESULTS: Respondent self-health state utility (mean and 95% confidence interval (CI)) was 0.79 (0.74-0.83). Utilities for hypothetical, untreated depression health states were: mild depression, 0.59 (0.55-0.62); moderate depression, 0.32 (0.29-0.34); severe depression, 0.04 (0.01-0.07). Fifty-six percent of respondents rated severe depression worse than being dead. Utilities for the hypothetical health states were not correlated with self-health utility. The intra-class correlation coefficient (ICC) was satisfactory for 13 of the 14 health states assessed. CONCLUSIONS: McSad was feasible and acceptable in patients with a history of major unipolar depression. The utilities for mild, moderate and severe untreated depression show the low health-related quality of life associated with depression. Initial assessments of test-retest reliability and validity yielded satisfactory results but further studies are needed to extend our knowledge of the measurement properties of McSad.

Cost and health related quality of life consequences of multiple sclerosis.

OBJECTIVES: To (i) quantify the cost of multiple sclerosis (MS) to the Canadian health care system and society; (ii) measure health utility in MS patients, and (iii) examine the influence of disability on patient utility and health care costs. MATERIALS AND METHODS: A comprehensive patient survey and chart review of relapsing MS patients in remission, relapse and recalling a relapse. RESULTS: Annual remission costs increased with EDSS level ($7596 at EDSS 1, $33 206 at EDSS 6). At all EDSS levels the largest costs were due to inability to work, which increased with EDSS. The average relapse cost for all EDSS levels was $1367. An inverse correlation was found between EDSS level and patient utility for patients in remission and relapse. The decrease in remission health utility from EDSS 1 to 6 was 0.24, which is 25% greater than the difference in health status between an average 25 and 85 year-old. CONCLUSIONS: This study demonstrates that MS produces substantial health care costs and reductions in patient quality of life and ability to work, losses that can be avoided or delayed if disease progression is slowed. These data provide health-care decision-makers with the opportunity to consider the full impact of MS when faced with budget allocation decisions.

The revised Canadian Guidelines for the Economic Evaluation of Pharmaceuticals.

The first edition of the Guidelines for Economic Evaluation of Pharmaceuticals: Canada was published in November 1994. At that time, the Canadian Coordinating Office for Health Technology Assessment (CCOHTA) was assigned the task of maintaining and regularly updating the Canadian Guidelines. Since their introduction, a great deal of experience has been gained with the practical application of the guidelines. Their role has also evolved over time, from being a framework for pharmacoeconomic research to the point where a wide variety of decision-makers use economic evaluations based on the principles set out in the guidelines as a means of facilitating their formulary decisions. In addition, methodologies in certain areas (and the body of related research literature in general) have developed considerably over time. Given these changes in the science and the experience gained, CCOHTA convened a multi-disciplinary committee to address the need for revisions to the guidelines. The underlying principles of the review process were to keep the guidance nature of the document, to focus on the needs of 'doers' (so as to meet the information needs of 'users') and to provide information and advice in areas of controversy, with sound direction in areas of general agreement. The purpose of this review is three-fold: (i) to outline the process which lead to the revision of the Canadian Guidelines; (ii) to describe the major changes made to the second edition of this document; and (iii) to consider the 'next steps' as they relate to the impact of such guidelines and the measurement of outcomes related to economic assessments of pharmaceuticals in general.

Assessing the value of a new pharmaceutical. A feasibility study of contingent valuation in managed care.

OBJECTIVES: The authors assessed the feasibility and construct validity of the contingent valuation method for measuring the monetary value to healthy enrollees in a health maintenance organization of a new drug, filgrastim, as prophylaxis against febrile neutropenia after chemotherapy treatment for cancer. METHODS: A random sample of 220 enrollees from a closed-panel staff-model health maintenance organization who did not have cancer were interviewed. Chemotherapy, febrile neutropenia and filgrastim were described by video and decision board. Questions were asked in two different scenarios: (1) User-based: Assuming they were at the point of consumption and about to receive chemotherapy, what is the maximum they would be willing to pay to receive filgrastim? and (2) Insurance-based: Given they were at risk of cancer in the future, what is the maximum they would be willing to pay in additional monthly insurance premiums to add filgrastim to the plan? In a second insurance scenario where respondents were told that filgrastim was covered, what is the minimum reduction in premium that persons were willing to accept to relinquish coverage of the drug? A 2 x 2 factorial design was used to contrast two bidding algorithms to test for starting point bias and two 5-yearly prior risks of cancer, 1/200 versus 1/100. Main effects were tested by ANCOVA controlling for age, sex, health, and income. RESULTS: Demographics of experimental cells were similar. No evidence was found of significant starting point bias. For user-based questions, as expected, willingness-to-pay increases with febrile neutropenia risk reduction, but at a declining marginal rate. Despite careful presentation of information to respondents, willingness-to-pay for insurance was higher in the lower prior risk group. Consistent with previous contingent valuation studies, the authors of the present study found evidence that willingness-to-accept exceeds willingness-to-pay for coverage of the same benefit. CONCLUSIONS: An insurance-based contingent valuation study is feasible in a health maintenance organization. Construct validation evidence was encouraging, with the exception of the test for prior risk of cancer; however, this was a between-person contrast and may have been confounded by other factors.

Cost effectiveness of multi-therapy treatment strategies in the prevention of vertebral fractures in postmenopausal women with osteoporosis.

OBJECTIVE: The aim of this study was to evaluate the cost effectiveness of multi-therapy treatment strategies in the prevention of vertebral fractures in postmenopausal women with osteoporosis. DESIGN: A retrospective, incremental cost-effectiveness analysis was conducted from a societal perspective. It compared 9 treatment strategies over 3 years and incorporated the willingness of patients to initiate and continue each therapy. MAIN OUTCOME MEASURES AND RESULTS: Four nondominated strategies formed the efficient frontier in the following order: (i) calcium-->no therapy; (ii) ovarian hormone therapy (OHT)-->calcium-->no therapy [166 Canadian dollars ($Can)]; (iii) OHT-->etidronate-->calcium-->no therapy ($Can2331); and (iv) OHT-->alendronate-->calcium-->no therapy ($Can40,965). The figures in parentheses are the incremental costs per vertebral fracture averted to move to that strategy from the previous strategy for patients who had undergone a hysterectomy. CONCLUSIONS: We identified 4 efficient multi-therapy strategies for the treatment of vertebral osteoporosis in postmenopausal women, 2 of which were consistent with the practice guidelines of the Osteoporosis Society of Canada. Decision-makers may select from among these efficient strategies on the basis of incremental cost effectiveness.

Health state utilities in knee replacement surgery: the development and evaluation of McKnee.

OBJECTIVE: 1. To develop McKnee, a classification system and direct utility measure for health states associated with knee replacement (KR) surgery. 2. To apply McKnee in a before-after study of KR surgery to: (i) gain experience with McKnee in an elderly population; (ii) confirm the practicality and usefulness of the McKnee system; (iii) assess self-health utility one week before and 3 mo after surgery; (iv) evaluate the stability of 3 clinical marker health states describing mild, moderate, and severe knee disability; (v) compare self-health utility scores with Short Form 36 (SF-36). METHODS: 1. Instrument development: The McKnee modified Health Utilities Index was developed and used to describe self-health and clinical marker health states: the clinical validity of the clinical marker states was evaluated by 5 clinicians involved in the care off KR patients. 2. Instrument evaluation: McKnee and the SF-36 were administered to 48 patients with osteoarthritis one week before and 3 mo after KR surgery. RESULTS: Before-after study: McKnee was feasible and acceptable in the older patient group studied (mean age in years, SD: 69.9, 8.6). No change in self-health utility (mean, SD) was observed at 3 mo postsurgery: before -0.78, 0.17; after -0.78, 0.21. On the SF-36, only the change scores for pain and health transition were statistically significant. Utilities (mean, SD) for the clinical marker health states were: mild -0.80, 0.20; moderate -0.55, 0.28; and severe -0.48, 0.31. The clinical marker mean utility scores were stable between the baseline and 3 mo assessment, but the intraclass correlation coefficients for individual scores were low. CONCLUSION: McKnee provides a preference based measure of health related quality of life that can be used to obtain and interpret clinically the knee disability utility scorers needed for cost-utility studies and medical decision-making models about KR surgery. The McKnee system provides a practical and useful method for classifying knee disability health states and obtaining direct measurements of utility scores for selected health states.