Re-examining the BMI threshold for bariatric surgery in the USA.

BACKGROUND: The optimal BMI threshold above which gastric bypass surgery should be offered to obese patients is controversial. The objective of this study was to compare the impact of Roux-en-Y gastric bypass (RYGB) vs. diet and exercise (D&E) on life expectancy to find the BMI at which patients experience an improvement in their life expectancy by undergoing surgery. METHODS: A Markov state transition model was designed to implement a decision tree that simulated the lives of obese patients. Life expectancies following RYGB and 2 years of D&E were estimated and compared. Ten thousand patients' lives were simulated in each weight-loss intervention group in the model. In addition to base case analysis (45 kg/m(2) BMI pre-intervention), sensitivity analysis of initial BMI at the start of the study was completed. Markov model parameters were extracted from the literature. RESULTS: The impact of RYGB on survival relative to D&E depended on the patient's initial BMI. Compared to patients who underwent 2 years of "optimal" diet and exercise (7 % total body weight loss/year), RYGB improved long-term survival for patients above a BMI of 31.3 kg/m(2). CONCLUSIONS: Roux-en-Y gastric bypass can improve long-term survival for patients with class I obesity. This study suggests that RYGB should not be reserved solely for patients with class II or III obesity.

Cost-effectiveness of a primary care intervention to treat obesity.

BACKGROUND: Data on the cost-effectiveness of the behavioral treatment of obesity are not conclusive. The cost-effectiveness of treatment in primary care settings is particularly relevant. METHODS: We conducted a within-trial cost-effectiveness analysis of a primary care-based obesity intervention. Study participants were randomized to: Usual Care (UC; quarterly visits with their primary care provider); Brief Lifestyle Counseling (BLC; quarterly provider visits plus monthly weight loss counseling visits) or Enhanced Brief Lifestyle Counseling (EBLC; all above interventions, plus choice of meal replacements or weight loss medication). A health-care payer perspective was used. Intervention costs were estimated from tracking data obtained prospectively. Quality-adjusted life years (QALYs) were estimated with the EuroQol-5D. We estimated cost per kilogram-year of weight loss and cost per QALY. RESULTS: Weight losses after 2 years were 1.7, 2.9 and 4.6 kg for UC, BLC and EBLC, respectively (P=0.003 for comparison of EBLC vs UC). The incremental cost per kilogram-year lost was $292 for EBLC compared with UC (95% confidence interval (CI): $219-$437). The short-term incremental cost per QALY was $115,397, but the 95% CI were undefined. Comparison of short-term cost per kg with published estimates of longer-term cost per QALY suggested that the intervention could be cost-effective over the long term (≥ 10 years). CONCLUSIONS: A primary care intervention that includes monthly counseling visits and a choice of meal replacements or weight loss medication could be a cost-effective treatment for obesity over the long term. However, additional studies are needed on the cost-effectiveness of behavioral treatment of obesity.

Direct medical cost of overweight and obesity in the USA: a quantitative systematic review.

To estimate per-person and aggregate direct medical costs of overweight and obesity and to examine the effect of study design factors. PubMed (1968-2009), EconLit (1969-2009) and Business Source Premier (1995-2009) were searched for original studies. Results were standardized to compute the incremental cost per overweight person and per obese person, and to compute the national aggregate cost. A total of 33 US studies met review criteria. Among the four highest-quality studies, the 2008 per-person direct medical cost of overweight was $266 and of obesity was $1723. The aggregate national cost of overweight and obesity combined was $113.9 billion. Study design factors that affected cost estimates included use of national samples vs. more selected populations, age groups examined, inclusion of all medical costs vs. obesity-related costs only, and body mass index cut-offs for defining overweight and obesity. Depending on the source of total national healthcare expenditures used, the direct medical cost of overweight and obesity combined is approximately 5.0% to 10% of US healthcare spending. Future studies should include nationally representative samples, evaluate adults of all ages, report all medical costs and use standard body mass index cut-offs.

Is treatment with ICS and LABA cost-effective for COPD? Multinational economic analysis of the TORCH study.

The TOwards a Revolution in COPD Health (TORCH) study was a 3-yr multicentre trial of 6,112 patients randomised to salmeterol (Salm), fluticasone propionate (FP), a Salm/FP combination (SFC) or placebo (P). Here the cost-effectiveness of treatments evaluated in the TORCH study is assessed. For four regions, 3-yr all-cause hospitalisation, medication and outpatient care costs were calculated. The sample was restricted to the 21 countries (n = 4,237) in which European quality of life five-dimension (EQ-5D) data were collected in order to estimate the number of quality-adjusted life years (QALYs). Regression models were fitted to survival, study medication cost, other medication cost and EQ-5D data in order to estimate total cost, number of QALYs and cost per QALY, adjusted for missing data and region. SFC had a trial-wide estimate of cost per QALY of 43,600 US dollars (USD) compared with P (95% confidence interval 21,400-123,500 USD). Estimates for Salm versus P (197,000 USD) and FP versus P (78,000 USD) were less favourable. The US estimates were greater than those from other regions; for SFC versus P, the cost per QALY was 77,100 (46,200-241,700) USD compared to 24,200 (15,200-56,100) USD in Western Europe. Compared with P, SFC has a lower incremental cost-effectiveness ratio than either FP or Salm used alone, and is, therefore, preferred to these monotherapies on the grounds of cost-effectiveness.

Economic analysis of conventional-dose chemotherapy compared with high-dose chemotherapy plus autologous hematopoietic stem-cell transplantation for metastatic breast cancer.

We performed an economic analysis of data from 180 women in a clinical trial of conventional-dose chemotherapy vs high-dose chemotherapy plus stem-cell transplantation for metastatic breast cancer responding to first-line chemotherapy. Data on resource use, including hospitalizations, medical procedures, medications, and diagnostic tests, were abstracted from subjects' clinical trial records. Resources were valued using the Medicare Fee Schedule for inpatient costs at one academic medical center and average wholesale prices for medications. Monthly costs were calculated and stratified by treatment group and clinical phase. Mean follow-up was 690 days in the transplantation group and 758 days in the conventional-dose chemotherapy group. Subjects in the transplantation group were hospitalized for more days (28.6 vs 17.8, P=0.0041) and incurred higher costs (US dollars 84055 vs US dollars 28169) than subjects receiving conventional-dose chemotherapy, with a mean difference of US dollars 55886 (95% CI, US dollars 47298-US dollars 63666). Sensitivity analyses resulted in cost differences between the treatment groups from US dollars 36528 to US dollars 75531. High-dose chemotherapy plus stem-cell transplantation resulted in substantial additional morbidity and costs at no improvement in survival. Neither the survival results nor the economic findings support the use of this procedure outside of the clinical trial setting.

Comparison of length of hospital stay for patients with known or suspected methicillin-resistant Staphylococcus species infections treated with linezolid or vancomycin: a randomized, multicenter trial.

STUDY OBJECTIVE: To compare hospital length of stay (LOS), weekly discharges, and days of antibiotic treatment with linezolid (intravenous with oral follow-up) and vancomycin (intravenous only). DESIGN: Multinational, randomized, phase III trial. SETTINGS: Hospitals in North America, Latin America, and Europe. PATIENTS: Four hundred sixty hospitalized patients with infections of known or suspected methicillin-resistant Staphylococcus species. INTERVENTION: Administration of linezolid or vancomycin. MEASUREMENTS AND MAIN RESULTS: For linezolid recipients, median LOS was 5 and 8 days shorter (p=0.05 and 0.003) in the complicated skin and soft tissue infection intent-to-treat (230 patients) and clinically evaluable (144) samples, and slightly but not significantly shorter in the overall intent-to-treat (460) and clinically evaluable (254) samples. In all samples, linezolid recipients had more discharges in the first week of treatment and fewer days of intravenous therapy than vancomycin recipients. CONCLUSION: Our results support linezolid's ability to reduce medical resource use.

A comparison of scoring weights for the EuroQol derived from patients and the general public.

OBJECTIVE: General health state classification systems, such as the EuroQol instrument, have been developed to improve the systematic measurement and comparability of health state preferences. In this paper we generate valuations for EuroQol health states using responses to this instrument's visual analogue scale made by patients enrolled in a randomized clinical trial evaluating tirilazad mesylate, a new drug used to treat subarachnoid haemorrhage. We then compare these valuations derived from patients with published valuations derived from responses made by a sample from the general public. METHODS: The data were derived from two sources: (1) responses to the EuroQol instrument from 649 patients 3 months after enrollment in the clinical trial, and (2) from a published study reporting a scoring rule for the EuroQol instrument that was based upon responses made by the general public. We used a linear regression model to develop an additive scoring rule. This rule enables direct valuation of all 243 EuroQol health states using patients' scores for their own health states elicited using a visual analogue scale. We then compared predicted scores generated using our scoring rule with predicted scores derived from a sample from the general public. RESULTS: The predicted scores derived using the additive scoring rules met convergent validity criteria and explained a substantial amount of the variation in visual analogue scale scores (R(2)=0.57). In the pairwise comparison of the predicted scores derived from the study sample with those derived from the general public, we found that the former set of scores were higher for 223 of the 243 states. Despite the low level of correspondence in the pairwise comparison, the overall correlation between the two sets of scores was 87%. CONCLUSIONS: The model presented in this paper demonstrated that scoring weights for the EuroQol instrument can be derived directly from patient responses from a clinical trial and that these weights can explain a substantial amount of variation in health valuations. Scoring weights based on patient responses are significantly higher than those derived from the general public. Further research is required to understand the source of these differences.

Quantifying stochastic uncertainty and presenting results of cost-effectiveness analyses.

In the last decade, major advances have been made in the statistical methods for quantifying uncertainty in stochastic cost-effectiveness studies. In this paper, we provide a guide to the literature in which we highlight the preferred methods for confidence interval estimation, new developments in the formulation of the cost-effectiveness problem, suggested ways for presenting results and the areas in which future research may develop. The overall approach taken is nontechnical, with an emphasis on graphical rather than algebraic presentation of methods.

Predicting 10-year care requirements for older people with suspected Alzheimer's disease.

OBJECTIVE: To describe the types and costs of care received for 10 years after the identification of an older person with suspected Alzheimer's disease (AD) by using data from 3254 patients with suspected AD who participated in the National Long Term Care Survey (NLTCS). METHODS: By using a Markov model derived using grade of membership techniques, the following were determined: survival probabilities at 10 years; years of survival during the 10 years; years in institutions; years with two or more impairments in basic activities of daily living; hours of paid and informal care while the older person lived in the community; and costs of paid community, institutional, and medical care. RESULTS: Greater degrees of cognitive impairment present when AD was identified were associated with reduced predicted probability of surviving 10 years, increased predicted number of years spent in institutions, increased hours of care required while affected individuals remained in the community, and increased costs of paid community, institutional, and medical care. Substantial differences between men and women were seen: severity-adjusted 10-year costs were almost two times higher for women with AD than for men ($75,000 compared with $44,000); according to sensitivity analysis, average 10-year costs might be as high as $109,000 for women and $67,000 for men. CONCLUSIONS: AD imposes a substantial burden on older persons. Interventions that slow the progression of the disease may therefore affect community survival as well as healthcare costs.

Relationship between CD4 count, viral burden, and quality of life over time in HIV-1-infected patients.

BACKGROUND: Although surrogate markers such as CD4 counts and viral burden (HIV-1 RNA) are predictive of AIDS-related disease progression, little is known about the relationship between changes in surrogate markers and health-related quality of life (HRQOL) outcomes. This study investigated how changes in CD4/mm3 and viral burden (RNA copies/mL) are related to changes in HRQOL as indexed by the Medical Outcomes Study HIV Health Survey (MOS-HIV-30). METHODS: Subjects were HIV-1-infected patients with CD4 counts <300/mm3 enrolled in a double-blind, randomized clinical trial of delavirdine. As part of the clinical protocol, patients completed the MOS-HIV-30, from which the Physical Health (PHS) and Mental Health (MHS) summary scores were used for analyses. HRQOL and surrogate marker data assessed up to 2 years after randomization were analyzed for a total of 1,112 patients. RESULTS: Individual patients' initial status (intercepts) and rates of change (slopes) over time for log CD4, log RNA, PHS, and MHS were estimated with the use of empirical Bayes. Early response to treatment correlated with HRQOL better for RNA than for CD4. However, the relationship between weekly change and HRQOL was stronger for CD4 than for RNA. CONCLUSIONS: Surrogate markers are significantly associated with HRQOL outcomes. Improvements in HRQOL over time are associated with lower initial viral load and with increases in CD4 counts. Limitations concerning the restricted variability of the change scores are addressed.

Towards a composite scoring solution for the Neurobehavioral Functioning Inventory.

Little research has been conducted towards the development and evaluation of a measure of quality of life specific to head/brain injury populations. Accordingly, we examined responses to the Neurobehavioral Functioning Inventory in the context of a clinical trial for head injury patients (n = 655) conducted in 14 countries. To reduce the 66 item scale into a smaller number of composite scales, principal components analysis was conducted. Scales were constructed assessing four categories of symptoms: cognitive deficits, depression, aggression and somatization. The internal reliabilities (alpha coefficient) of the four scales were generally acceptable (range = 0.79-0.92). Scores on all four scales correlated significantly with patient-rated overall quality of life and all but the aggression scale correlated significantly with overall clinical severity. The need for more formal evaluation of this and other disease-specific measures is discussed.

Determining an episode of care using claims data. Diabetic foot ulcer.

OBJECTIVE: Amid changes in the organization and financing of health care, health care decision makers are increasingly interested in episodes of care. We sought to determine an episode of care for diabetic foot ulcer using an administrative claims database. RESEARCH DESIGN AND METHODS: We used 1993-1995 claims data to assess resource utilization for privately insured patients with diabetic foot ulcers. Over a 26-week period, we determined the episode length by comparing differences in average daily charges and proportion of patients with charges before and after foot ulcer diagnosis. All 13 weeks before diagnosis were used to calculate baseline values. Significance was determined by CIs, which were calculated by a nonparametric bootstrap technique. Costs associated with the episode were also calculated. A sensitivity analysis using weeks with highest and lowest values as baseline was also conducted. RESULTS: Based on average daily charges, the episode of care for diabetic foot ulcer was 5 weeks. Using proportion of patients with charges, the episode was longer than 13 weeks. The cost for an episode of care ranged from $900 to $2,600. In the sensitivity analyses, episodes of care ranged from 1 to 13 weeks. CONCLUSIONS: Episodes of care can be defined by the period beginning with increased resource consumption and ending when resource consumption returns to baseline levels. With the growth of managed care and disease management programs, episode-of-care analysis may have an increasingly important role in health care provision and delivery.

Analytic approaches for the evaluation of costs.

Currently, economic evaluation of new medical therapies is conducted routinely. Development of an analysis plan before performance of the analysis is a first step in the analysis of data from such evaluations. Univariate analysis of costs can be performed with both parametric and nonparametric tests. Potential multivariable analyses include ordinary least squares regression, nonparametric hazard models, parametric failure time models, Cox semiparametric regression, and joint distributions of survival and cost. In addition to developing point estimates for economic outcomes, 95% confidence intervals for cost-effectiveness ratios should be developed to evaluate the level of uncertainty that surrounds these estimates. Sensitivity analysis should be used to address other sources of uncertainty.

A comparison of preference assessment instruments used in a clinical trial: responses to the visual analog scale from the EuroQol EQ-5D and the Health Utilities Index.

OBJECTIVES: To compare preference assessments that were made by using the EuroQol EQ-5D and the Health Utilities Index Mark II. SUBJECTS: 561 patients in a randomized trial of tirilazad mesylate for aneurysmal subarachnoid hemorrhage. MEASURES: Three preference assessments (a value score for the EuroQol instrument and value and utility scores for the Health Utilities Index) made three months after randomization. The averages for each of the three scores, stratified by clinical outcomes and attributes of the Health Utilities Index health status classification system, were compared. To evaluate potential sources of difference between the instruments, the authors estimated two alternative Health Utilities Index scoring rules that were based on patient responses to the EuroQol instrument. RESULTS: Patients' ratings of their current health made by using the 100-point visual analog scale from the EuroQol instrument were more similar to the utility scores for the Health Utilities Index than they were to the value scores for the Health Utilities Index. The biggest differences between the visual analog scores for the EuroQol instrument and the utility scores for the Health Utilities index were seen at higher levels of functioning. CONCLUSION: For states representing higher levels of functioning, differences were seen between patients' self-ratings obtained by using the EuroQol instrument and the patients' utility scores on the Health Utilities Index; for states representing lower levels of functioning, substantial agreement was observed between these two scores. Differences observed at the higher levels of functioning suggest that further research is needed to determine whether the Health Utility Index's assignment of a score of 1.0 to the reference state representing being healthy is appropriate.

Clinical economics in clinical trials: the measurement of cost and outcomes in the assessment of clinical services through clinical trials.

As the population ages and more expensive high-technology services become available, health care costs continue to spiral upward. Because the financial resources for health care are limited, economic analysis can help to evaluate expenditures and set priorities. Economic analysis of medical technology or medical care evaluates a medical service by comparing its dollar cost with its dollar benefit (cost-benefit), by measuring its dollar cost in relation to its outcomes (cost-effectiveness) as well as in relation to its utility or quality-adjusted outcomes (cost-utility), or simply by tabulating the costs involved (cost-identification). Direct costs are generated as services are provided. In addition, patients' productivity is affected, and these costs can be considered, especially in determining the benefit of a service that decreases morbidity or mortality. Intangible costs are those of pain, suffering, and grief. The point of view, or perspective, of the study determines the costs and benefits that will be measured in the analysis. Sensitivity analysis, which can evaluate the stability of the conclusions to the data used, is an important assessment within economic analysis. Economic analysis of new pharmaceutical therapies is increasingly being incorporated into clinical trials. Although there are some limitations of pharmacoeconomic information in clinical studies of drug safety and efficacy, these trials are often the only opportunity for economic data collection before adoption and reimbursement decisions are made. Validation after the drug has been introduced should complement economic information developed from clinical trials.

Clinical and economic impact of a combination Haemophilus influenzae and Hepatitis B vaccine: estimating cost-effectiveness using decision analysis.

BACKGROUND: Compliance with hepatitis B virus (HBV) vaccine remains suboptimal, despite a recommendation by the Advisory Committee on Immunization Practices of the US Public Health Service that all newborns be vaccinated. Although a combined HBV-Haemophilus influenzae type b (Hib) vaccine may improve acceptance of the HBV vaccine, the clinical and economic consequences of this intervention are uncertain. OBJECTIVES: To compare the health impact and cost-effectiveness of the following 2 immunization strategies: current practice of administering HBV vaccine separately (75% compliance) and Hib vaccine alone or as part of a multivalent vaccine (95% compliance); and strategy of delivering a combined HBV-Hib vaccine (95% compliance). DESIGN: A Markov model simulated the natural history of acute and chronic HBV and Hib disease in a cohort of US newborns. Clinical and economic variables were obtained from published reports. RESULTS: The Hib-related outcomes were the same in both strategies, because the efficacy and compliance with Hib vaccine were assumed to be equivalent in both. A 53% reduction in the number of cases of HBV infection with the combination strategy (n = 8541) was estimated when compared with current practice (n = 18 044), along with 205 fewer HBV-related deaths per 1 million infants. Immunization costs of the combination strategy were $11.5 million higher than for current practice ($108.4 million compared with $96.9 million), whereas the cost of HBV-related disease was $4.0 million lower than in current practice. The incremental cost-effectiveness ratio for the combination strategy was $17700 per year of life saved. CONCLUSION: An HBV-Hib vaccine in US infants yields substantial benefits, with a cost-effectiveness ratio that is lower than that of many commonly used medical interventions.

Estimating country-specific cost-effectiveness from multinational clinical trials.

Because costs and outcomes of medical treatments may vary from country to country in important ways, decision makers are increasingly interested in having data based on their own country's health care situations. This paper proposes methods for estimating country-specific cost-effectiveness ratios from data available from multinational clinical trials. It examines how clinical and economic outcomes interact when estimating treatment effects on cost and proposes empirical methods for capturing these interactions and incorporating them when making country-specific estimates. We use data from a multinational phase III trial of tirilazad mesylate for the treatment of subarachnoid haemorrhage to illustrate these methods. Our findings suggest that it is possible for meaningful country-by-country differences to be found in such trial data. These differences can be useful in informing reimbursement, utilization, and other decisions taken at the country level.

Empirical criteria for the selection of quality-of-life instruments for the evaluation of peripheral blood progenitor cell transplantation.

We propose a method for selecting quality-of-life instruments for use in phase III trials using the convergent validity of patient responses collected in phase I and II clinical trials. Two generic and two disease-specific instruments were administered to patients with breast cancer undergoing peripheral blood progenitor cell mobilization and transplantation. They included the visual analog scale from the EuroQoL EQ5D instrument, the SF-36, the European Organization for Research and Treatment of Cancer (EORTC)-QLQ-C30, and the Functional Assessment of Cancer Therapy instrument. No single instrument was found to have superior convergent validity in all domains, but the EORTC-QLQ-C30 seemed to perform better than the SF-36.

Prospective economic evaluation accompanying a trial of GM-CSF/IL-3 in patients undergoing autologous bone marrow transplantation for Hodgkin's and non-Hodgkin's lymphoma. IL-3 BMT Study Team.

Our objective was to assess the economic impact of a new cytokine therapy that was being compared to standard therapy as supportive care in patients receiving autologous bone marrow transplantation for treatment of lymphoma. We performed an economic study accompanying a multicenter, randomized, controlled clinical trial in academic medical centers. One hundred and fifteen patients consented to participate in a parallel economic study of a randomized controlled trial of sequential IL-3 followed by GM-CSF vs GM-CSF alone after autologous bone marrow transplantation. We measured costs and quality-adjusted survival over a 13-month follow-up period. For the 13-month study period, the total cost estimates were $79892 (95% CI $69343 to $90544) for patients receiving GM-CSF alone and $89651 (95% CI $79769 to $102114) for patients receiving IL-3/GM-CSF. The difference was not statistically significant. During the 13-month study period, the total number of quality-adjusted life-months in the GM-CSF arm was 6.67 (95% CI 5.75 to 7.56) months, while the total number of quality-adjusted life-months in the IL-3 arm was 6.26 (95% CI 5.34 to 7.15) months. The difference in quality-adjusted life-months between the two treatment arms was not statistically significant. We conclude that economic analysis of a phase III clinical trial of IL-3/GM-CSF compared with GM-CSF alone showed no significant effect of IL-3 on the costs of care for patients undergoing bone marrow transplantation for a period of up to 13 months after the procedure. This study demonstrates the feasibility of prospective economic evaluation within phase III trials of new cancer therapies. Data from this type of economic protocol could be used to help physicians, patients and managed care organizations understand the effect of new treatments from both a clinical and an economic perspective.