Comparison of the rating scale and the standard gamble in measuring patient preferences for outcomes of gallstone disease

Modeling Optimal Clinical Thresholds for Elective Abdominal Hernia Repair in Patients With Cirrhosis

IMPORTANCE

Patients with cirrhosis have increased risk of postoperative mortality. Several models have been developed to estimate this risk; however, current risk estimation scores cannot compare surgical risk with the risk of not operating.

OBJECTIVE

To identify clinical optimal thresholds to favor operative or nonoperative management for a common cirrhosis surgical scenario, the symptomatic abdominal hernia.

DESIGN, SETTING, AND PARTICIPANTS

This was a Markov cohort decision analytical modeling study evaluating elective surgery vs nonoperative management for a symptomatic abdominal hernia in a patient with cirrhosis. Transition probabilities and utilities were derived from the literature and from data using an established cirrhosis cohort in the Veterans Health Administration. Participants included patients who were referred to a surgery clinic for a symptomatic abdominal hernia. Data were obtained from patients diagnosed with cirrhosis between January 1, 2008 and December 31, 2018. Data were analyzed from January 1 to May 1, 2022.

MAIN OUTCOMES AND MEASURES

Expected quality-adjusted life-years (QALYs) were estimated for each pathway and iterated over baseline model for end-stage liver disease-sodium (MELD-Na) scores ranging from 6 to 25. Markov models were cycled over a 5-year time horizon.

RESULTS

A total 2740 patients with cirrhosis (median [IQR] age, 62 [56-66] years; 2699 [98.5%] men) were referred to a surgery clinic for a symptomatic abdominal hernia; 1752 patients (63.9%) did not receive surgery. The median (IQR) follow-up was 42.1 (25.3-70.0) months. Using this cohort to estimate the mortality risk of operative and nonoperative pathways, an initial MELD-Na threshold of 21.3 points, below which surgery was associated with maximized QALYs was identified. Nonoperative management was associated with increased QALYs above this MELD-Na threshold. Although more patients experienced death with a surgical treatment decision across all initial MELD-Na values, this was counterbalanced by increased time spent in a resolved hernia state associated with increased utility. Model results were sensitive to the probability of hernia recurrence and hernia incarceration and utility decrement in the symptomatic hernia state.

CONCLUSIONS AND RELEVANCE

This decision analytical model study found that elective surgical treatment for a symptomatic abdominal hernia was favored even in the setting of relatively high MELD-Na scores. Patient symptoms, hernia-specific characteristics, and surgeon and center expertise may potentially impact the optimal strategy, emphasizing the importance of shared decision-making.

The price is right: Routine fluorescent cholangiography during laparoscopic cholecystectomy

BACKGROUND

Early experience with indocyanine green-based fluorescent cholangiography during laparoscopic cholecystectomy suggests the potential to improve outcomes. However, the cost-effectiveness of routine use has not been studied. Our objective was to evaluate the cost-effectiveness of fluorescent cholangiography versus standard bright light laparoscopic cholecystectomy for noncancerous gallbladder disease.

METHODS

A Markov model decision analysis was performed comparing fluorescent cholangiography versus standard bright light laparoscopic cholecystectomy alone. Probabilities of outcomes, survival, toxicities, quality-adjusted life-years, and associated costs were determined from literature review and pooled analysis of currently available studies on fluorescent cholangiography (n = 37). Uncertainty in the model parameters was evaluated with 1-way and probabilistic sensitivity analyses, varying parameters up to 40% of their means. Cost-effectiveness was measured with an incremental cost-effectiveness ratio expressed as the dollar amount per quality-adjusted life-year.

RESULTS

The model predicted that fluorescent cholangiography reduces lifetime costs by $1,235 per patient and improves effectiveness by 0.09 quality-adjusted life-years compared to standard bright light laparoscopic cholecystectomy. Reduced costs were due to a decreased operative duration (21.20 minutes, P < .0001) and rate of conversion to open (1.62% vs 6.70%, P < .0001) associated with fluorescent cholangiography. The model was not influenced by the rate of bile duct injury. Probabilistic sensitivity analysis found that fluorescent cholangiography was both more effective and less costly in 98.83% of model iterations at a willingness-to-pay threshold of $100,000/quality-adjusted life year.

CONCLUSION

The current evidence favors routine use of fluorescent cholangiography during laparoscopic cholecystectomy as a cost-effective surgical strategy. Our model predicts that fluorescent cholangiography reduces costs while improving health outcomes, suggesting fluorescence imaging may be considered standard surgical management for noncancerous gallbladder disease. Further study with prospective trials should be considered to verify findings of this predictive model.

Valuing the health states associated with breast cancer screening programmes: A systematic review of economic measures

Policy decisions regarding breast cancer screening and treatment programmes may be misplaced unless the decision process includes the appropriate utilities and disutilities of mammography screening and its sequelae. The objectives of this study were to critically review how economic evaluations have valued the health states associated with breast cancer screening, and appraise the primary evidence informing health state utility values (cardinal measures of quality of life). A systematic review was conducted up to September 2018 of studies that elicited or used utilities relevant to mammography screening. The methods used to elicit utilities and the quality of the reported values were tabulated and analysed narratively. 40 economic evaluations of breast cancer screening programmes and 10 primary studies measuring utilities for health states associated with mammography were reviewed in full. The economic evaluations made different assumptions about the measures used, duration applied and the sequalae included in each health state. 22 evaluations referenced utilities based on assumptions or used measures that were not methodologically appropriate. There was significant heterogeneity in the utilities generated by the 10 primary studies, including the methods and population used to derive them. No study asked women to explicitly consider the risk of overdiagnosis when valuing the health states described. Utilities informing breast screening policy are restricted in their ability to reflect the full benefits and harms. Evaluating the true cost-effectiveness of breast cancer screening will remain problematic, unless the methodological challenges associated with valuing the disutilities of screening are adequately addressed.

Utility elicitation in adults and children for allergic rhinoconjunctivitis and associated health states

Purpose

Allergic rhinitis and asthma symptoms are detrimental to health-related quality of life (HRQoL). Health technology appraisal agencies often require cost–utility analysis when assessing new interventions. Appropriate utility estimates, which quantify the value of different conditions in cost–utility analyses, are scarce for allergic rhinitis and asthma health states. This study aimed to generate utilities for allergic rhinitis and asthma health states from a European general population sample of adults and children.

Methods

Health state descriptions incorporating symptoms, impact of symptoms on daily life and symptom treatment were developed using clinical guidelines. Descriptions were amended with clinician and patient input, and incorporated into a survey in which each health state was followed by a standard gamble (adults) or visual analogue scale (children) item. The survey was distributed to samples of adults and children aged 8 to 11 from four European countries that were stratified to represent the general population within that country.

Results

1454 adults and 1082 children completed the survey. Mean health utilities ranged from 0.635 to 0.880 and those elicited in children were lower (0.635 to 0.705) than those elicited in adults (0.812 to 0.880). Disutilities assessing the impact of increased allergic rhinitis severity and comorbidities were also greater in children than in adults.

Conclusions

Symptoms of allergic rhinitis and asthma were valued as having a clinically meaningful impact on HRQoL. Children valued health states as poorer than adults, and further research should investigate whether this reflects true preferential differences or results from methodological and/or comprehension differences between the two groups.

Electronic supplementary material

The online version of this article (10.1007/s11136-018-1910-8) contains supplementary material, which is available to authorized users.

Early laparoscopic cholecystectomy is more cost-effective than delayed laparoscopic cholecystectomy in the treatment of acute cholecystitis

Background

This economic evaluation quantifies the cost-effectiveness of early laparoscopic cholecystectomy (ELC) versus delayed laparoscopic cholecystectomy (DLC) in the management of acute cholecystitis. The two interventions were assessed in terms of outcome measures, including utilities, to derive quality-adjusted life years (QALYs) as a unit of effectiveness. This study hypothesizes that ELC is more cost-effective than DLC.

Materials and methods

In this economic evaluation, existing literature was compiled and analyzed to estimate the incremental cost-effectiveness of ELC versus DLC. Six randomized controlled trials were used to schematically represent the probabilities of each decision tree branch. To calculate health outcomes, quality of life scores were sourced from three articles and multiplied by the expected length of life postintervention to give QALYs. From an National Health Service (NHS) perspective, one QALY may be sacrificed if the incremental cost-effectiveness ratio is above £20,000–£30,0000 in cost savings.

Results

This economic evaluation calculated the average net present values of ELC to be £3920 and DLC to be £4565, demonstrating that ELC is the less-expensive intervention, with potential cost savings of £645 per operation. When scaling these savings up to a population approximately comparable to the size of the UK, full-scale implementation of ELC rather than DLC will potentially save the NHS £30,000,000 per annum.

Conclusion

ELCs are cost-effective from the perspective of the NHS. As such, policy should review existing guidelines and consider the merits of ELC versus DLC, improving resource allocation. The findings of this article advocate that ELC should become a standard practice.

A Systematic Review of the Techniques Used to Value Temporary Health States

BACKGROUND

A broad literature on health state utility values exists, but compared with chronic health states (HSs), issues surrounding the valuation of temporary health states (THSs) have been poorly explored.

OBJECTIVES

To assess the methods used by previous studies to value HSs that are considered temporary so as to determine the strengths and limitations associated with various approaches and to inform future study designs.

METHODS

A systematic review was undertaken to explore the methods used, assess how the valuation was conducted for diseases that might lead to HSs deemed as temporary, and identify the challenges encountered in the valuation of THSs.

RESULTS

Of the 36 relevant studies, 22 were explicit that the HS being valued was temporary. Most of the studies used more than one technique (often incorporating both conventional and adapted approaches). In using adapted techniques, the primary challenge was identifying an appropriate intermediate "anchor" HS and the possibility of negative utilities.

CONCLUSIONS

There is no agreement on the most methodologically robust approach to THS valuation. Valuation is complex and important issues relating to the validity, practicality, and reliability of the techniques used were not adequately covered by most of the studies identified.

RAPP, a systematic e-assessment of postoperative recovery in patients undergoing day surgery: study protocol for a mixed-methods study design including a multicentre, two-group, parallel, single-blind randomised controlled trial and qualitative interview studies

INTRODUCTION

Day surgery is a well-established practice in many European countries, but only limited information is available regarding postoperative recovery at home though there is a current lack of a standard procedure regarding postoperative follow-up. Furthermore, there is also a need for improvement of modern technology in assessing patient-related outcomes such as mobile applications. This article describes the Recovery Assessment by Phone Points (RAPP) study protocol, a mixed-methods study to evaluate if a systematic e-assessment follow-up in patients undergoing day surgery is cost-effective and improves postoperative recovery, health and quality of life.

METHODS AND ANALYSIS

This study has a mixed-methods study design that includes a multicentre, two-group, parallel, single-blind randomised controlled trial and qualitative interview studies. 1000 patients >17 years of age who are undergoing day surgery will be randomly assigned to either e-assessed postoperative recovery follow-up daily in 14 days measured via smartphone app including the Swedish web-version of Quality of Recovery (SwQoR) or to standard care (ie, no follow-up). The primary aim is cost-effectiveness. Secondary aims are (A) to explore whether a systematic e-assessment follow-up after day surgery has a positive effect on postoperative recovery, health-related quality of life (QoL) and overall health; (B) to determine whether differences in postoperative recovery have an association with patient characteristic, type of surgery and anaesthesia; (C) to determine whether differences in health literacy have a substantial and distinct effect on postoperative recovery, health and QoL; and (D) to describe day surgery patient and staff experiences with a systematic e-assessment follow-up after day surgery.The primary aim will be measured at 2 weeks postoperatively and secondary outcomes (A-C) at 1 and 2 weeks and (D) at 1 and 4 months.

TRIAL REGISTRATION NUMBER

NCT02492191; Pre-results.

Clinical effectiveness and cost-effectiveness of cholecystectomy compared with observation/conservative management for preventing recurrent symptoms and complications in adults presenting with uncomplicated symptomatic gallstones or cholecystitis: a systematic review and economic evaluation

BACKGROUND

Approximately 10-15% of the adult population suffer from gallstone disease, cholelithiasis, with more women than men being affected. Cholecystectomy is the treatment of choice for people who present with biliary pain or acute cholecystitis and evidence of gallstones. However, some people do not experience a recurrence after an initial episode of biliary pain or cholecystitis. As most of the current research focuses on the surgical management of the disease, less attention has been dedicated to the consequences of conservative management.

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of cholecystectomy compared with observation/conservative management in people presenting with uncomplicated symptomatic gallstones (biliary pain) or cholecystitis.

DATA SOURCES

We searched all major electronic databases (e.g. MEDLINE, EMBASE, Science Citation Index, Bioscience Information Service, Cochrane Central Register of Controlled Trials) from 1980 to September 2012 and we contacted experts in the field.

REVIEW METHODS

Evidence was considered from randomised controlled trials (RCTs) and non-randomised comparative studies that enrolled people with symptomatic gallstone disease (pain attacks only and/or acute cholecystitis). Two reviewers independently extracted data and assessed the risk of bias of included studies. Standard meta-analysis techniques were used to combine results from included studies. A de novo Markov model was developed to assess the cost-effectiveness of the interventions.

RESULTS

Two Norwegian RCTs involving 201 participants were included. Eighty-eight per cent of people randomised to surgery and 45% of people randomised to observation underwent cholecystectomy during the 14-year follow-up period. Participants randomised to observation were significantly more likely to experience gallstone-related complications [risk ratio = 6.69; 95% confidence interval (CI) 1.57 to 28.51; p = 0.01], in particular acute cholecystitis (risk ratio = 9.55; 95% CI 1.25 to 73.27; p = 0.03), and less likely to undergo surgery (risk ratio = 0.50; 95% CI 0.34 to 0.73; p = 0.0004), experience surgery-related complications (risk ratio = 0.36; 95% CI 0.16 to 0.81; p = 0.01) or, more specifically, minor surgery-related complications (risk ratio = 0.11; 95% CI 0.02 to 0.56; p = 0.008) than those randomised to surgery. Fifty-five per cent of people randomised to observation did not require an operation during the 14-year follow-up period and 12% of people randomised to cholecystectomy did not undergo the scheduled operation. The results of the economic evaluation suggest that, on average, the surgery strategy costs £1236 more per patient than the conservative management strategy but was, on average, more effective. An increase in the number of people requiring surgery while treated conservatively corresponded to a reduction in the cost-effectiveness of the conservative strategy. There was uncertainty around some of the parameters used in the economic model.

CONCLUSIONS

The results of this assessment indicate that cholecystectomy is still the treatment of choice for many symptomatic people. However, approximately half of the people in the observation group did not require surgery or suffer complications in the long term indicating that a conservative therapeutic approach may represent a valid alternative to surgery in this group of people. Owing to the dearth of current evidence in the UK setting a large, well-designed, multicentre trial is needed.

STUDY REGISTRATION

The study was registered as PROSPERO CRD42012002817.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Patient preferences for side effects associated with cervical cancer treatment

OBJECTIVES

The aim of this study was to assess patient preferences regarding side effects associated with cervical cancer treatment.

METHODS/MATERIALS

The visual analog scale (VAS) and modified standard gamble (SG) were used to elicit preferences of women with no evidence of disease after primary treatment of cervical cancer. Higher scores on VAS and SG indicated more favorable ratings for a given health state. Health states (HS) included vaginal shortening, diarrhea, dietary changes, menopause, moderate nausea/vomiting, rectal bleeding, sexual dysfunction, and urinary self-catheterization. Descriptive statistics, Kruskal-Wallis, Mann-Whitney U, and Wilcoxon signed-ranks tests and correlation coefficients were used for statistical analysis.

RESULTS

Seventy-eight patients participated in the study. Median age was 44.1 years (range, 24.9-67.8 years). Median time since treatment completion was 31.2 months (range, 1.0-113.3 months). The HSs rated as most favorable by VAS were also rated as most favorable by SG. Increasing age was associated with higher VAS scores for menopause and vaginal shortening (P = 0.04 and 0.036). African Americans had higher VAS scores for dietary changes (P = 0.05), sexual dysfunction (P = 0.028), and diarrhea (P = 0.05) when compared with Hispanic and non-Hispanic white patients. Women receiving radiation had more favorable VAS scores for menopause compared with women undergoing radical hysterectomy (P = 0.05). Women receiving chemotherapy rated urinary self-catheterization less favorably by VAS score compared with those not receiving chemotherapy (P = 0.045).

CONCLUSIONS

Multiple demographic and clinical factors influence the severity of treatment-related adverse effects perceived by women surviving cervical cancer. A better understanding of factors influencing patient preferences regarding treatment side effects will allow providers to formulate care better tailored to the individual desires of each patient.

Cost-effectiveness of elective laparoscopic cholecystectomy versus observation in older patients presenting with mild biliary disease

Our objective was to determine the probability threshold for recurrent symptoms at which elective cholecystectomy compared to observation in older patients with symptomatic cholelithiasis is the more effective and cost-effective option. We built a decision model of elective cholecystectomy versus observation in patients >65 presenting with initial episodes of symptomatic cholelithiasis that did not require initial hospitalization or cholecystectomy. Probabilities for subsequent hospitalization, emergency cholecystectomy, and perioperative complications were based on previously published probabilities from a 5 % national sample of Medicare patients. Costs were estimated from Medicare reimbursements and from the Healthcare Cost and Utilization Project. Utilities (quality-adjusted life years, QALYs) were obtained from established literature estimates. Elective cholecystectomy compared to observation in all patients was associated with lower effectiveness (-0.10 QALYs) and had an increased cost of $3,422.83 per patient at 2-year follow-up. Elective cholecystectomy became the more effective option when the likelihood for continued symptoms exceeded 45.3 %. Elective cholecystectomy was both more effective and less costly when the probability for continued symptoms exceeded 82.7 %. An individualized shared decision-making strategy based on these data can increase elective cholecystectomy rates in patients at high risk for recurrent symptoms and minimize unnecessary cholecystectomy for patients unlikely to benefit.

Systematic review of the clinical and cost effectiveness of cholecystectomy versus observation/conservative management for uncomplicated symptomatic gallstones or cholecystitis

BACKGROUND

Gallstone disease is a common gastrointestinal disorder in industrialised countries. Although symptoms can be severe, some people can be symptom free for many years after the original attack. Surgery is the current treatment of choice, but evidence suggests that observation is also feasible and safe. We reviewed the evidence on cholecystectomy versus observation for uncomplicated symptomatic gallstones and conducted a cost-effectiveness analysis.

METHODS

We searched six electronic databases (last search April 2014). We included randomised controlled trials (RCTs) or non-randomised comparative studies where adults received either cholecystectomy or observation/conservative management for the first episode of symptomatic gallstone disease (biliary pain or cholecystitis) being considered for surgery in secondary care. Meta-analysis was used to combine results. A de novo Markov model was developed to assess the cost effectiveness of the interventions.

RESULTS

Two RCTs (201 participants) were included. Eighty-eight percent of people randomised to surgery and 45 % of people randomised to observation underwent cholecystectomy during the 14-year follow-up period. Participants randomised to observation were significantly more likely to experience gallstone-related complications (RR = 6.69, 95 % CI = 1.57-28.51, p = 0.01), in particular acute cholecystitis (RR = 9.55, 95 % CI = 1.25-73.27, p = 0.03), and less likely to undergo surgery (RR = 0.50, 95 % CI = 0.34-0.73, p = 0.0004) or experience surgery-related complications (RR = 0.36, 95 % CI = 0.16-0.81, p = 0.01) than those randomised to surgery. Fifty-five percent of people randomised to observation did not require surgery, and 12 % of people randomised to cholecystectomy did not undergo surgery. On average, surgery costs £1,236 more per patient than conservative management, but was more effective.

CONCLUSIONS

Cholecystectomy is the preferred treatment for symptomatic gallstones. However, approximately half the observation group did not require surgery or suffer complications indicating that it may be a valid alternative to surgery. A multicentre trial is needed to establish the effects, safety and cost effectiveness of observation/conservative management relative to cholecystectomy.

The utility of health and wealth

Tradeoffs between health and wealth are among the most important decisions individuals make, and are central to social and economic policy. Yet, only a few studies have investigated the utility of health and wealth empirically. This paper investigates this utility function both theoretically and empirically. We conduct detailed personal interviews with 180 cancer patients, and also obtain questionnaires from 132 diabetes patients. We find strong support for the utility function U(h, w)=h·log(w), where h denotes health and w denotes wealth.

Utilities and disutilities for attributes of injectable treatments for type 2 diabetes

INTRODUCTION

Although cost-utility models are frequently used to estimate treatment outcomes for type 2 diabetes, utilities are not available for key attributes of injectable treatments. The purpose of this study was to identify the utility or disutility of three injection-related attributes (dose frequency, dose flexibility, injection site reaction) that may influence patient preference.

METHODS

Patients with type 2 diabetes in Scotland completed standard gamble (SG) interviews to assess the utility of hypothetical health states and their own current health state. The EQ-5D, PGWB, IWQOL-Lite, and QIDS were also administered. Construct validity and differences among health states were examined.

RESULTS

A total of 151 patients completed interviews. Of the three injection-related attributes, dose frequency was the only attribute with a statistically significant impact on utility (in a multiple regression model, p = 0.01). Weekly injections were associated with an average added utility of 0.023 in comparison to everyday injections. Flexible dosing and injection site reactions resulted in somewhat smaller utility shifts that were in the expected directions (+0.006 and -0.011, respectively). SG utility of current health (mean = 0.897) demonstrated construct validity through statistically significant correlations with patient-reported outcome measures.

DISCUSSION

The three injection attributes were associated with small utility shifts in the expected directions. Dose frequency appears to be the most important of the three attributes from the patients' perspective. The vignette-based SG approach was feasible and useful for assessing added utility or disutility of injection-related attributes associated with treatments for type 2 diabetes.

Neck pain patients' preference scores for their current health

Purpose

To elicit neck pain (NP) patients’ preference scores for their current health, and investigate the association between their scores and NP disability.

Methods

Rating scale scores (RSs) and standard gamble scores (SGs) for current health were elicited from chronic NP patients (n = 104) and patients with NP following a motor vehicle accident (n = 116). Patients were stratified into Von Korff Pain Grades: Grade I (low-intensity pain, few activity limitations); Grade II (high-intensity pain, few activity limitations); Grade III (pain with high disability levels, moderate activity limitations); and Grade IV (pain with high disability levels, several activity limitations). Multivariable regression quantified the association between preference scores and NP disability.

Results

Mean SGs and RSs were as follows: Grade I patients: 0.81, 0.76; Grade II: 0.70, 0.60; Grade III: 0.64, 0.44; Grade IV: 0.57, 0.39. The association between preference scores and NP disability depended on type of NP and preference-elicitation method. Chronic NP patients’ scores were more strongly associated with depressive symptoms than with NP disability. In both samples, NP disability explained little more than random variance in SGs, and up to 51% of variance in RSs.

Conclusion

Health-related quality-of-life is considerably diminished in NP patients. Depressive symptoms and preference-elicitation methods influence preference scores that NP patients assign to their health.

Health utilities in patients with HIV/AIDS in Thailand

OBJECTIVES

We measured health utility (HU) in Thai HIV/AIDS patients using visual analog scale (VAS), EuroQOL (EQ-5D), and standard gamble (SG), determine the relationships between these HU measures and health-related quality of life (HRQOL) measures of HIV and patient characteristics, and assess the feasibility of the HU methods.

METHODS

A sample of 120 HIV/AIDS patients was identified at Bamrasnaradura Infectious Disease Institute, Thailand, during September to December, 2004. Face-to-face interviews included VAS, SG, and EQ-5D, HRQOL assessment using the Thai abbreviated version of the World Health Organization quality of life (WHOQOL-BREF THAI) and HIV-related symptom instruments, questions about ease of understanding HU approaches and sociodemographic items. Data were analyzed with repeated-measures ANOVA, followed by Dunn-Bonferroni t-test, intraclass coefficients (ICC), Spearman's rank correlation, and multiple linear regressions.

RESULTS

The mean (95% confidence interval) HUs were as follows: VAS, 0.79 (0.76-0.82); EQ-5D, 0.80 (0.77-0.84); and SG, 0.65 (0.60-0.70). A significant difference in HU by method was found (P < 0.001). Agreement by ICC was 0.71 for VAS versus EQ-5D, 0.41 for VAS versus SG, and 0.38 for EQ-5D and SG. The regression models showed that WHOQOL-BREF THAI, frequency of HIV symptoms, and patient characteristics could explain approximately 50% of the variation in the VAS and the EQ-5D and 20% in the SG(2). Among these three HU methods, the SG was the most difficult task.

CONCLUSION

VAS, EQ-5D and SG yielded different HUs for this sample. VAS and EQ-5D showed stronger construct validity with other health measures than SG. From a feasibility perspective, the SG was the least satisfactory of the three approaches.

Obese versus non-obese patients with type 2 diabetes: patient-reported outcomes and utility of weight change

INTRODUCTION

This study (1) used patient-reported outcome measures to assess and compare the health status of type 2 diabetes patients with and without obesity and (2) assessed the value of weight change among obese and non-obese subgroups, using standard gamble (SG) utility methodology.

METHODS

Among a sample with type 2 diabetes in the United Kingdom, individuals with obesity (BMI > or = 30 kg/m2) were identified and compared to non-obese patients. Patients completed the EQ-5D, Psychological General Well-Being Index, Appraisal of Diabetes Symptoms, and Diabetes Symptom Checklist-Revised (DSC-R). SG interviews assessed the utility of the 'basic' type 2 diabetes health state anchored to respondents' body weight, as well as health states with altered weight.

RESULTS

A total of 129 patients (74 obese; 55 non-obese) completed interviews (mean age 55.9 years; 64.3% male). Obese patients reported lower health status (EQ-5D VAS; between-group difference: p < 0.001) and greater symptom impact (several DSC-R scales, p < 0.05). Utilities of the basic health state were 0.86 (obese) and 0.91 (non-obese; p = 0.02). Hypothetical health states with higher weight received lower utilities, whereas reduced weight was associated with increased utility. There was a between-group difference in the disutility associated with 5% higher weight (obese 0.068; non-obese 0.051; p = 0.03).

DISCUSSION

Compared with non-obese patients, the obese group reported lower health status and greater symptom impact. SG interviews found an inverse relationship between weight and utility. Furthermore, obese patients with type 2 diabetes may value weight change differently than non-obese patients. Study limitations include the sample size and the use of a patient sample, rather than a sample selected from the general population. Overall, the results demonstrate that utilities can differ by patient subgroups, even among patients with the same diagnosis.

Utilities and disutilities for type 2 diabetes treatment-related attributes

INTRODUCTION

Although cost-utility analyses are frequently used to estimate treatment outcomes for type 2 diabetes, utilities are not available for key medication-related attributes. The purpose of this study was to identify the utility or disutility of diabetes medication-related attributes (weight change, gastrointestinal side effects, fear of hypoglycemia) that may influence patient preference.

METHODS

Patients with type 2 diabetes in Scotland and England completed standard gamble (SG) interviews to assess utility of hypothetical health states and their own current health state. The EQ-5D, PGWB, and Appraisal of Diabetes Symptoms were administered. Construct validity and differences among health states were examined with correlations, t-tests, and ANOVAs.

RESULTS

A total of 129 patients (51 Scotland; 78 England) completed interviews. Mean utility of diabetes without complications was 0.89. Greater body weight was associated with disutility, and lower body weight with added utility (e.g., 3% higher = -0.04; 3% lower = +0.02). Gastrointestinal side effects and fear of hypoglycemia were associated with significant disutility (p < 0.001). SG utility of current health (mean = 0.87) demonstrated construct validity through correlations with patient-reported outcome measures (r = 0.08-0.31).

DISCUSSION

The vignette-based approach was feasible and useful for assessing added utility or disutility of medication-related attributes.

Using preference-based measures to assess quality of life in stuttering

PURPOSE

The purpose of this study was to determine whether standard pharmaco-economic preference methods can be used to assess perceived quality of life in stuttering.

METHOD

Seventy-five nonstuttering adults completed a standardized face-to-face interview that included a rating scale, standard gamble, and time trade-off preference measures for 4 health states (your health and mild, moderate, and severe stuttering) in the context of 2 anchor states (perfect health and death).

RESULTS

Results showed mean utility values between .443 for severe stuttering estimated using the rating scale technique and .982 for respondents' own current health estimated using a standard gamble technique. A two-way repeated measures analysis of variance and post hoc tests showed significant effects for method, health state, and the interaction.

CONCLUSIONS

These results confirm that utility estimates can differentiate between stuttering severity levels and that utility scores for stuttering conform to the known properties of data obtained using these standard measurement techniques. These techniques, therefore, can and should be further investigated as potential contributors to complete measurement protocols for the study and treatment of stuttering.

Assessment of health state utilities for attention-deficit/hyperactivity disorder in children using parent proxy report

This study used standard gamble (SG) utility interviews to assess parent preferences for health states of childhood attention-deficit/hyperactivity disorder (ADHD). Health state utilities are needed to calculate quality-adjusted life years (QALYs), a critical outcome measure in cost-effectiveness studies of new treatments. Parents (n = 43) of children diagnosed with ADHD completed SG utility interviews, rating their child's current health and 11 hypothetical health states describing untreated ADHD and ADHD treated with a stimulant or non-stimulant. Parents completed questionnaires on their children's symptoms and health-related quality of life (HRQL). Parents' SG rating of their child's current health state (mean of 0.74 on a utility scale ranging from 0 to 1) was significantly correlated with inattentive, hyperactive, and overall ADHD symptoms (r = 0.37, 0.36, and 0.40 respectively; p < 0.05) and psychosocial HRQL domains. Hypothetical health state utilities ranged from 0.48 (severe untreated ADHD) to 0.88 (effective and tolerable non-stimulant treatment). Comparisons between health states found expected differences between untreated mild, moderate, and severe ADHD health states. When both treatments were effective and tolerable, parents preferred the non-stimulant health state over the stimulant health state (p < 0.03). Results suggest that parent SG interviews are a feasible and useful method for obtaining utility scores that can be used in cost-effectiveness models of ADHD treatment.

'Threats' to and hopes for estimating benefits

In a recent paper in this journal, Andrew Lloyd reviewed some potential threats to the estimation of health care benefits in monetary terms. Particular emphasis was placed on the extent to which the use of non-compensatory heuristics may distort the results. Although it is useful to be reminded of these problems, Lloyd's paper does not do justice to the attention such issues have already received, and continue to receive, within Health Economics. The aim of this paper is twofold. Firstly, it seeks to provide a more balanced and comprehensive view of the evidence by considering some of the methodological work that health economists have conducted in many of the areas pointed out by Lloyd. Secondly, and more importantly, it suggests ways to combine the economic and psychological views of human decision-making, providing a much more positive perspective to all those researchers out there who recognize the necessity of using stated preference methods to inform health policy.

Health state utilities for childhood attention-deficit/hyperactivity disorder based on parent preferences in the United kingdom

OBJECTIVES

The purpose of this study was to use standard gamble (SG) utility interviews to assess parent preferences for health states of childhood attention-deficit/hyperactivity disorder (ADHD).

METHODS

The study was conducted in August 2003 in London, England. Parents (N=83) of children diagnosed with ADHD completed SG utility interviews, rating their child's current health and 14 hypothetical health states describing untreated ADHD and ADHD treated with a nonstimulant, immediate-release stimulant, or extended-release stimulant. Raw temporary utilities ranging from 0 (worst health) to 1 (best health) were adjusted to a chronic utility scale ranging from 0 (death) to 1 (best health) using a linear transformation. Parents rated the severity of their children's ADHD symptoms using the Attention-Deficit/Hyperactivity Disorder Rating Scale-IV (ADHD-RS) and their children's health-related quality of life using the EuroQol EQ-5D.

RESULTS

Raw and adjusted SG ratings of hypothetical health states ranged from 0.63-0.90 and 0.88-0.96, respectively. Parents' raw SG scores of their child's current health state (mean=0.72) were significantly correlated with inattentive, hyperactive, and overall ADHD symptoms (r=-0.25, -0.27, -0.27; P <0.05) and the EQ-5D visual analogue scale (r=0.26; P <0.05).

CONCLUSION

This UK-based study suggests that parent SG interviews are a valid method for obtaining utilities for child ADHD-related health states. The utilities obtained in this study would be appropriate for use in a cost-utility analysis evaluating the costs and benefits of childhood ADHD treatments in the United Kingdom.

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.

Transhiatal vs extended transthoracic resection in oesophageal carcinoma: patients' utilities and treatment preferences

To assess patients' utilities for health state outcomes after transhiatal or transthoracic oesophagectomy for oesophageal cancer and to investigate the patients' treatment preferences for either procedure. The study group consisted of 48 patients who had undergone either transhiatal or transthoracic oesophagectomy. In an interview they were presented with eight possible health states following oesophagectomy. Visual Analogue Scale and standard gamble techniques were used to measure utilities. Treatment preference for either transhiatal or transthoracic oesophagectomy was assessed. Highest scores were found for the patients' own current health state (Visual Analogue Scale: 0.77; standard gamble: 0.97). Lowest scores were elicited for the health state "irresectable tumour" (Visual Analogue Scale: 0.13; standard gamble: 0.34). The Visual Analogue Scale method produced lower estimates (P<0.001) than the standard gamble method for all health states. Most patient characteristics and clinical factors did not correlate with the utilities. Ninety-five per cent of patients who underwent a transthoracic procedure and 52% of patients who underwent a transhiatal resection would prefer the transthoracic treatment. No significant associations between any patient characteristics or clinical characteristics and treatment preference were found. Utilities after transhiatal or transthoracic oesophagectomy were robust because they generally did not vary by patient or clinical characteristics. Overall, most patients preferred the transthoracic procedure.

Measuring women's preferences for breast cancer treatments and BRCA1/BRCA2 testing

In establishing decision models in the treatment and prevention of breast cancer, it is important to evaluate patients' preferences for such interventions. The objectives of the present study were: (i) to characterize women's preferences for breast cancer treatments and BRCA1/BRCA2 testing, using the rating scale and standard gamble techniques; and (ii) to identify factors associated with these quality of life indices. Data were collected from women with breast cancer (n = 60), high-risk relatives of women with breast cancer (n = 58), and women in the general population (n = 51). Regardless of group membership, participants favoured treatment and prevention options that involved minimal physical invasiveness. Women with breast cancer rated lumpectomy and radiation treatment more highly than high-risk relatives and women in the general population. Preferences did not differ according to participants' intentions to undergo BRCA testing. Age was the only demographic variable associated with health state preferences. These findings hold implications for the application of patient preferences to clinical decision making.

Investigating women's preferences for intrapartum care: home versus hospital births

There is an increasing amount of evidence to suggest that the clinical outcomes associated with a home birth for low risk women are at least as good, if not better than, the clinical outcomes associated with giving birth in hospital. If it is the case that there is little or no difference in clinical outcomes between the two modes of delivery, then traditional measures of benefit used in health economics, e.g. quality adjusted life years (QALYs), would detect little or no difference between the alternative modes of delivery. From this, the conclusion would be that the utility values associated with each mode of delivery are similar. However, women may still have clearly defined preferences relating to the way in which maternity care is provided. This paper uses the economic technique of conjoint analysis to assess the relative value attached to several main characteristics associated with the process of maternity care during the intrapartum stage for women who have actively chosen to give birth at home relative to women who have given birth in hospital. It was found that respondents who had chosen a home birth valued continuity of carer, a homely environment and the ability to make their own decisions about what happens during labour and delivery. In contrast, hospital birth respondents placed a relatively high value on access to an epidural for pain relief and not needing to be transferred to another location during labour if a problem arose. The results of the study suggest that women have clearly defined preferences for characteristics associated with the process of intrapartum care that would be unlikely to be detected by traditional benefit measures used in health economics. This finding is important where policy issues relating to aspects of maternity care service delivery are being considered.

Economics of surgery

The time has come to subject surgery to the same rigours of economic assessment that other health-care sectors are already receiving--namely, the comparative assessment of costs and benefits. The surgical management of gallstones provides a good example of the role of economics in surgery. Gallstone disease is common and patients are usually referred to a surgeon, but the threshold for intervention is not agreed and varies widely, with considerable implications for resources. Gallstone removal has been subject to much innovation over the past 10 years, yet economic assessment of laparoscopic and "mini" cholecystectomy and of gallstone lithotripsy is rare, despite the fact that operation rates have increased by up to 50% in some countries. For surgery to compete with other interventions, economic assessment of new surgical techniques will be increasingly important. This assessment should be based on well-conducted clinical trials in which interventions are provided in a routine service setting, and in which benefits are assessed among other things on the basis of the patient's perceived quality of life. Economic assessment often needs data beyond those collected in a clinical trial, however pragmatic the trial design, so modelling will often be required, incorporating a range of sources of evidence. Finally, evidence alone will not be enough to promote cost-effective practices. The take-up of surgical techniques will always be affected by the way hospitals and surgeons are remunerated. Affecting practice requires a realistic system of reimbursement that reflects evidence on cost effectiveness.

Assessing health-related quality of life in cataract patients: the relationship between utility and health-related quality of life measurement

The relationship between health-related quality of life (HQL) measures and patient preference for their health status was studied. Study subjects consisted of 132 patients at four hospitals who were scheduled for cataract surgery. Generic and disease-specific health status measures were determined in study subjects. The Medical Outcomes Study Short-form 36 (SF-36) item health status instrument was used to measure generic health status and the Visual Function 14 (VF-14) item visual health status instrument was used as the disease-specific health measure. Preference for general health and visual health was measured by assessing utilities assigned by patients to certain health states. Utilities assigned for general health were correlated with all categories of the SF-36 and VF-14 scores. Utilities assigned for visual health were correlated with four categories of the SF-36 (role limitation due to emotional health, general health, physical functioning, and vitality) and VF-14 scores. Utilities assigned for visual health were more strongly correlated with VF-14 scores than generic measures of health. Verbal ratings for visual health were correlated with Snellen visual acuity (SVA) (r = 0.20), utilities assigned for visual health (r = 0.58), VF-14 scores (r = 0.74), all categories of the SF-36 (r values ranging from 0.21 to 0.28), utilities assigned for general health (r = 0.19), and verbal ratings for general health (r = 0.29). Utility measures and verbal ratings for general and visual health were shown to be appropriate HQL measures. These measures were strongly correlated with other established generic and disease-specific health measures and should be included in the array of health status measures.

Sensitivity and perspective in the valuation of health status: whose values count?

The literature was studied on the existence of differences in valuation for hypothetical and actual health states between patients and other-rater groups. It was found that nine different study designs have been used to study this question and two of these designs were applied in a study involving dialysis patients and other rater groups. In the first study, both dialysis patients and students had to value hypothetical health states with Standard Gamble (SG) and Time Trade Off (TTO). Patients assigned higher values to hypothetical health states than students did. In the second study, dialysis patients who were being treated with four different dialysis modalities were asked to value their own health state with SG, TTO and a visual analogue scale (EQ(VAS)), and to describe their health state on the EQ-5D(profile). Several EQ-5D(index) values (health index values derived from general population samples) were calculated for the four dialysis treatment groups, based on the EQ-5D(profile). These health indexes could discriminate between treatment groups, according to clinical impressions. Treatment groups could not be differentiated based on patients' valuations of own health state. The results suggest that general population samples, using EQ-5D(index) values, may be more able to discriminate between patient groups than the patients themselves are. The implications of this finding for valuation research and policy-making are discussed.

Assessing convergent validity of health-state utilities obtained using different scaling methods

A number of empirical studies have attempted to assess the convergent validity of health-state utilities obtained using two or more scaling methods (standard gamble, time tradeoff, rating scale, magnitude estimation, equivalence technique, and willingness-to-pay). The data from these studies can be mapped onto an N x K matrix, where N and K are the numbers of respondents and health states, respectively, and each matrix cell consists of a pair of health-state utilities, one obtained using scaling method X and the other obtained using scaling method Y. The Pearson's rassessing convergent validity can then be computed as 1) the unraveled correlation over all N x K data pairs, 2) the mean within-respondent correlation, 3) the mean within-health-state correlation, or 4) the correlation of the across-respondents means. These four different ways of computing the correlation do not necessarily yield the same results. The appropriateness of each method of computing the correlation is considered.

Feasibility, validity and test-retest reliability of scaling methods for health states: the visual analogue scale and the time trade-off

The feasibility, validity and reliability of the Time Trade-Off (TTO) and Visual Analogue Scale (VAS) methods in obtaining preference values for health states were compared in a random sample of the Spanish population (n = 294). Respondents valued 43 EuroQol-5D health states in face-to-face interviews. Convergent validity was assessed by examining the relationship between values, and the effect of sociodemographic and health variables on values was used as a means of assessing construct validity. Test-retest reliability was analysed in a subgroup of 50 respondents, using the intraclass correlation coefficient (ICC) and generalisability theory. Rates of non-response and missing data were low on both methods, though the VAS took considerably less time to administer. VAS and TTO values correlated highly (r = 0.92), though there were differences in the ordering of health states between methods, and in the number of health states rated worse than death. VAS values were compressed into a considerably smaller valuation space than TTO values. Respondents in higher educational categories assigned higher TTO values to 12 health states. Mean ICCs (95% CI) at individual level were 0.90 (0.88-0.92) and 0.84 (0.81-0.87) for the VAS and TTO, respectively. Generalisability analysis showed variance due to time to be 0 for both methods. In conclusion, the VAS was more feasible and slightly more reliable than the TTO, whilst doubt can be cast on the degree of convergent validity existing between the two methods. The compression of VAS values means that the TTO is likely to discriminate better between health states, and it may have greater construct validity if results from larger samples confirm that there are genuine differences between sociodemographic subgroups.

Measuring patient preferences by willingness to pay to avoid: the case of acute otitis media

The aim of this study was to evaluate willingness to pay (WTP) to avoid as a method of eliciting relative values for use in expected-value (EV) decision making. Parents' preferences for the events and outcomes associated with acute otitis media (AOM) and its treatment were quantified by means of a questionnaire asking how much they would be willing to pay to avoid them. Their responses were then used to calculate the EVs of treating or not treating presumed AOM with antibiotics. The advantages of the WTP method were its simplicity, its analogy with everyday financial transactions, its explicit recognition of illness and its management as involving decreases in value, and its face validity. The disadvantages included the need to use another method (the standard gamble) to derive a value for death and the wide ranges and the poor test-retest reliability of individual parents' responses. Nonetheless, median WTP values and their ranges may prove useful in defining for physicians and policymakers the parameters of their practical management decisions. In the case of AOM, the EV of treating with antibiotics was, for the aggregate sample and for most individual parents, robustly superior because of parents' desire to avoid any increased risk of their children's death.

Patients' utilities for cancer treatments: a study of the chained procedure for the standard gamble and time tradeoff

OBJECTIVE

Temporary health states cannot be measured in the traditional way by means of techniques such as the time tradeoff (TTO) and the standard gamble (SG), where health states are chronic and are followed by death. Chained methods have been developed to solve this problem. This study assesses the feasibility of a chained TTO and a chained SG, and the consistency and concordance between the two methods.

PATIENTS AND METHODS

Seventy female early-stage breast cancer patients were interviewed. In using both chained methods, the temporary health state to be evaluated was weighed indirectly with the aid of a temporary anchor health state. The patients were asked to evaluate their actual health states, a hypothetical radiotherapy scenario, and a hypothetical chemotherapy scenario.

RESULTS

Sixty-eight patients completed the interview. The use of the anchor health state yielded some problems. A significant difference between the means of the TTO and the SG was found for the anchor health state only. For the other health states, the results were remarkably close, because the design avoided some of the bias effects in traditional measurements.

CONCLUSION

The feasibility and the consistency of the chained procedure were satisfactory for both methods. The problems regarding the anchor health state can be solved by adapting the methods and by the use of a carefully chosen anchor health state. The chained method avoids biases present in the conventional method, and thereby the TTO and the SG may be reconciled. Moreover, there are several psychological advantages to the method, which makes it useful for diseases with uncertain prognoses.

Alternative approaches to valuing intangible health losses: the evidence for multiple sclerosis

This study uses both risk-risk and risk-dollar approaches to assess intangible health losses associated with multiple sclerosis (MS). Using an estimation approach that adjusts for potential perceptional biases that may effect the expressed risk tradeoffs, we estimated parameters of the utility function of persons with and without MS as well as the degree of subjects" overestimation of the probability of obtaining MS. The sample included subjects from the general population and persons with MS. We found that marginal utility of income is lower in the state with MS than without it. However, the difference in marginal in two states was greater for persons without MS than for those with the disease. Persons with MS overestimated the probability of acquiring MS to a greater extent than did persons within MS. Correcting for overestimation of this probability, the value of intangible loss of a statistical case of MS derived from responses of the general population was US$350,000 to US$500.000. Persons with MS were willing to pay somewhat more than this (D80,118,J17).

Valuing temporary and chronic health states associated with breast screening

The aim of this study was to derive quality of life values for the four key breast screening outcomes (true negative, false positive, true positive and false negative), including the quality of life effects of the screening and treatment processes. In doing so, methodological issues in health status measurement were explored, in particular the valuation of temporary health states. The true negative and false positive descriptions were temporary health states, lasting for short term durations (12 months) and the true positive and false negative outcomes were chronic health states lasting for long term durations (rest of life). Descriptions of breast screening outcomes were valued using the time trade-off technique and the visual analogue scale. Paired comparisons between TTO values for states with the same duration found a difference between the true negative and the false positive time trade-off values but no difference for true positive and false negative descriptions. The TTO values for the false positive were low. The study highlights several important methodological issues such as the use of the two stage procedure for valuing temporary health states, the impact of duration on values, the impact of anchor points, and the importance of qualitative analysis of respondents values. Further empirical testing of all these issues is recommended.

Assessment of the time-tradeoff values for prophylactic mastectomy of women with a suspected genetic predisposition to breast cancer

BACKGROUND

Female carriers of the breast-cancer-susceptibility genes BRCA1 and BRCA2 are at high risk for breast cancer (85%). They face the choice between prophylactic mastectomy (PM) and breast cancer screening. For this treatment choice, a shared-decision-making program was developed. In this program, the time tradeoff (TTO) was used to assess preferences for PM.

PURPOSE

Assessment of the feasibility, constant proportional tradeoff, and reliability of using the TTO for this purpose.

METHODS

Fifty-four women suspected to carry the BRCA1/2 mutation were provided with comprehensive relevant information. Their preferences for PM were assessed on two occasions. Discrepancies between preferences indicated by the two tests were resolved by testing a third time. The preferences assessed on the last occasion were used for individual decision analyses. In order to test constant proportional tradeoff, the TTO consisted of four items with different numbers of life years.

RESULTS

Forty-two women (78%) completed the TTO twice and nine women (17%) performed the test a third time. Three women (5%) completed the TTO only once. The mean TTO value for PM at the last replication was 0.69 (SD=0.30). Violations of constant proportional tradeoff were significant: the largest tradeoffs were recorded for the shortest durations. Pearson's correlation coefficient between the TTO values for the two last sessions was 0.96.

CONCLUSION

Assessment of individual preferences by the TTO in this patient group is feasible and reliable. Therefore, the TTO can be used in clinical settings to elicit treatment preferences of women proven or suspected to have a genetic predisposition to breast cancer.

Value measurement in cost-utility analysis: explaining the discrepancy between rating scale and person trade-off elicitations

Previous studies have shown a discrepancy between common utility elicitation methods, such as rating scale (RS) elicitations, and person trade-off (PTO) elicitations. This discrepancy has generally been felt to be due to the fact that RS elicitations ask people to compare conditions to each other in terms of numbers on a visual rating scale, while PTO elicitations ask people to think in terms of numbers of people needing to be treated. However, there are three other cognitive differences between PTO and RS elicitations that might contribute to the discrepancy: In PTO elicitations, as opposed to RS elicitations: (1) people are asked to think about how conditions affect people other than themselves; (2) people are asked to think about the benefit of treating conditions; and (3) people are asked to chose who to treat among patients with different conditions. In this study, we attempt to determine whether any of three cognitive differences contribute to the discrepancy between RS and PTO utility elicitations. We randomized prospective jurors to receive one of several survey versions in which we manipulated the RS and PTO elicitations to reduce the differences between them, while preserving their underlying structure. In the RS-self survey, we asked subjects to rate a health condition on a scale from 0 to 100 as if they had the condition. In the RS-other survey, we asked people to rate the health condition as if someone else had it. In the RS-cure survey, we asked subjects to rate the benefits of curing someone else of the health condition. In the PTO-comparison survey, we asked people to determine equivalent numbers of people needing to be cured of two conditions in order to produce equal benefits. In the PTO-choice survey, we presented people with a budget constraint and asked them to determine equivalent numbers of people needing to be cured of two conditions to help decide which group should be treated within the budget constraint. Two hundred and twenty two subjects completed surveys. Median utilities for health conditions were higher in the two PTO elicitations than in the three RS elicitations. There were no differences in utilities across the two PTO surveys, nor across the three RS surveys. In addition, the PTO elicitations allowed people to make finer distinctions among non-life threatening conditions than did the RS elicitations. The discrepancy between RS and PTO elicitations cannot be explained by shifting subjects attentions from themselves to others, nor from conditions to the benefit of treating conditions. Instead, the discrepancy occurs because of the general format of RS and PTO elicitations.

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.

Preference values for visual states in patients planning to undergo cataract surgery

To assess how preference values that cataract surgery patients assign to their preoperative visual states relate to visual acuity and problems in specific aspects of daily life, the authors interviewed 47 patients scheduled to have cataract surgery. Using a rating-scale technique with a scale from 0 (death) to 1 (excellent health), the patients had a mean preference value of 0.68 for their preoperative vision. Patients' preference values for their preoperative vision were more closely related to problems in specific aspects of daily life (especially feelings of depression and problems interacting with people) than to visual acuity in the operative eye, better eye, or worse eye, or a weighted average of visual acuities in both eyes. These results provide a rationale for relying more on patients' views about the effects of visual impairment than on measures of visual acuity when assessing the need for cataract surgery.

The effect of assessment method and respondent population on utilities elicited for Gaucher disease

Measured preferences have been reported to vary with the method of elicitation and respondent population surveyed. We elicited utilities for Gaucher disease using a multimedia implementation of the time trade-off, standard gamble, and a conceptually different, largely untested approach, the risk-risk trade-off, from those who are healthy, those with a chronic illness and those with Gaucher disease. The risk-risk trade-off produced significantly lower utilities than the other two preference assessment methods and had the poorest test-retest reliability. The respondent's self-rated current health state utility was the most important determinant of utility values elicited by the time trade-off and standard gamble for the hypothetical health states. Our results do not support the use of our implementation of the risk-risk trade-off method. In eliciting preferences for hypothetical health states from the general population, the subjective rating of a respondent's own health state should be considered in determining representative population groups.

Prevention of recurrences of erosive reflux esophagitis: a cost-effectiveness analysis of maintenance proton pump inhibition

PURPOSE

To determine the cost-effectiveness of three management strategies for healed erosive reflux esophagitis: maintenance therapy with a proton pump inhibitor (PPI) from the outset; no maintenance therapy unless a patient's symptoms recur once over a year; and no maintenance therapy unless a patient's symptoms recur twice over a year.

MATERIALS AND METHODS

Decision analysis using data from randomized trials of lansoprazole, case series, and expert opinion.

RESULTS

For patients with grade 4 esophagitis, maintenance from the outset is the most efficient approach. For all other patients, providing maintenance PPI after a patient experiences two recurrences is the least costly but least effective approach. The other two approaches prevent more recurrences: waiting to initiate maintenance therapy until symptoms recur once requires an additional $73 for each recurrence prevented whereas maintenance PPI from the outset requires an additional $819 for each recurrence prevented. Maintenance therapy from the outset is cost effective if symptoms of esophagitis cause a 22% or greater decrement in quality of life (using $50,000 per quality-adjusted life year gained as a cost-effectiveness definition). However, withholding maintenance until the time of a first recurrence is cost effective if symptoms cause a 2% or greater decrement in quality of life.

CONCLUSION

For grades 2 and 3 esophagitis, providing maintenance therapy after a patient experiences a further recurrence is a preferred option that appears cost-effective across a wide array of assumptions. Maintenance therapy from the outset, however, appears cost-effective only for those patients who report a significant decline in quality of life associated with esophagitis or for those patients with baseline grade 4 esophagitis.

Can preference scores for discrete states be used to derive preference scores for an entire path of events? An application to prenatal diagnosis

The authors conducted a study exploring whether preferences for sequences of events can be approximated by preferences for component discrete states. Visual-analog-scale (VAS) and standard-gamble (SG) scores for a subset of the possible sequences of events (path states) and component temporary and chronic outcomes (discrete states) that can follow prenatal diagnostic decisions were elicited from 121 pregnant women facing a choice between chorionic villus sampling and amniocentesis. For individuals, preference scores for path states could not be predicted easily from discrete-state scores. Mean path-state VAS scores, however, were predicted reasonably accurately by multiple regression models (R2 = 0.85 and 0.82 for two different anchoring schemes), with most measured scores lying within the 95% confidence intervals of the derived scores. It is concluded that, for individual patient decision making, preferences for path states should be elicited. When mean preference values for a population are sought, however, it may be reasonable to derive regression weights from a subset of respondents and then to apply those weights to preferences for discrete states elicited from a larger group.