Predicting EQ-5D values using the SGRQ.

OBJECTIVES: The purpose of this study was to develop and validate an algorithm that predicts EQ-5D utility from the St. George's Respiratory Questionnaire (SGRQ) in subjects with chronic obstructive pulmonary disease and to examine the effect of using this algorithm in predicting quality-adjusted life-years (QALYs). METHODS: In the TORCH (Towards a Revolution in COPD Health) trial, the SGRQ and EQ-5D were administered at baseline and every 24 weeks for 3 years. To map EQ-5D utility from the SGRQ, ordinary least squares (OLS), generalized linear models (GLMs) and two-part models were used. Algorithms were developed in a fitting sample and used to predict utility scores in a validation sample and selected based on root-mean-square error (RMSE). QALYs were estimated from the algorithm and compared to QALYs derived from EQ-5D utility scores collected in the trial. RESULTS: A simple OLS algorithm was found to perform as well as algorithms developed using more complex modeling structures. The resulting model was (RMSE 0.1723): EQ-5D = 0.9617 - 0.0013 × SGRQ total - 0.0001 × SGRQ total(2) + 0.0231 × male. Ordering of treatments by QALY gain was dependent on the method of utility estimation. CONCLUSION: A mapping algorithm can be used to predict EQ-5D utility scores from the SGRQ and may be useful in some situations; however, for use in a health technology assessment (HTA) submission in which precision of estimation is important, it is in the interests of both the manufacturer and the HTA body that utility scores be directly derived from the clinical trial population.

Economic efficiency of genetic screening to inform the use of abacavir sulfate in the treatment of HIV.

BACKGROUND: Abacavir sulfate (abacavir) is associated with a hypersensitivity reaction (HSR) that affects 5-8% of patients. While serious complications are rare, failure to identify it, or abacavir re-challenge following HSR, can be fatal. Genetic screening for HLA-B*5701 can identify patients who are likely to experience an HSR and reduces the incidence of the reaction. OBJECTIVE: We assessed the intrinsic and practical value, from the US healthcare system perspective, of prospective HLA-B*5701 screening among a population of antiretroviral-naive patients without elevated risk factors for cardiovascular disease, plasma HIV RNA >100,000 copies/mL, or pre-existing renal insufficiency. METHODS: Two approaches were used to evaluate the costs and benefits of prospective screening. First, the efficiency of HLA-B*5701 screening compared with no screening prior to abacavir initiation (intrinsic value of screening) was evaluated using a 60-day decision-tree model. Next, the practical value of screening was assessed using a lifetime discrete-event simulation model that compared HLA-B*5701 screening prior to abacavir use versus initiation with a tenofovir-containing regimen. Screening-effectiveness parameters were taken from an open-label trial that incorporated screening prior to abacavir initiation and other published studies. Treatment efficacy was derived from clinical trials. Modelling assumptions, costs ($US, year 2007 values) and other parameters were derived from published sources, primary data analysis and expert opinion. Multiple one-way sensitivity and scenario analyses were performed to assess parameter uncertainty. The primary outcome measure for the short-term screening versus no screening analysis was cost per patient. For the long-term analysis, outcomes were presented as QALYs. Costs and effects were discounted at 3% per year. RESULTS: Over the first 60 days of treatment, prospective screening prior to abacavir initiation cost an additional $US17 per patient and avoided 537 HSRs per 10,000 patients. The per-patient cost of screening was sensitive to the cost of the genetic test, HSR costs and screening performance. In the lifetime model, screening-informed abacavir use was more effective and less costly than initiation with a tenofovir-containing regimen in the base case and in sensitivity analyses. CONCLUSIONS: Our results suggest that prospective HLA-B*5701 screening prior to abacavir initiation produces cost savings and should become a standard component of HIV care.

Cost-effectiveness of fluticasone propionate/salmeterol (500/50 microg) in the treatment of COPD.

OBJECTIVE: We examine the lifetime cost-effectiveness of treatment with fluticasone propionate/salmeterol (500/50 microg) compared with no maintenance treatment in COPD in the US. METHODS: A decision-analytic model was developed to estimate lifetime costs and outcomes associated with fluticasone propionate/salmeterol 500/50 microg treatment, salmeterol 50 microg, and fluticasone propionate 500 microg compared to no maintenance treatment in treating COPD from a third-party US payer perspective. The patient population was similar to that of the TORCH clinical trial. Model structure and inputs were obtained from published literature and clinical trial data. All costs are presented in 2006 US dollars. Outcomes included cost per life year (LY) saved and cost per quality-adjusted life year (QALY) gained. Costs and outcomes were discounted at 3% annually. Univariate and multivariate sensitivity analyses were conducted to assess model robustness. RESULTS: Compared to no maintenance treatment, treatment with fluticasone propionate/salmeterol 500/50mug results in a lifetime incremental cost-effectiveness ratio (ICER) of $33,865/QALY. Treatment with salmeterol 50 microg was found to have an ICER of $20,797/QALY. These results are robust to changes in input parameters. Fluticasone propionate 500 microg was dominated by no treatment, though the results were not robust to changes in parameters. CONCLUSIONS: Treatment of COPD with fluticasone propionate/salmeterol 500/50 microg appears to be cost-effective (

Pharmacoeconomics in COPD: lessons for the future.

COPD exerts a substantial burden on health and health care systems globally and will continue to do so for the foreseeable future. Treatment however can be costly and health care providers are interested in both whether treatments can offer improvements in disease burden and whether they represent value for money. Economic evaluations seek to resolve this issue by producing results that can be used to inform and assist the decision maker in allocating scarce health care resources. In this paper we introduce economic evaluation and then use these themes to review and critically appraise the existing COPD economic evaluations, in order to assess quality in light of today's standards. The use of existing economic evaluations in informing the decision maker is then discussed. Ten out of the fifteen studies were clinical trial or observational study based, and the remaining five on a decision analytic model. Study design, interventions, outcome measures and the use of uncertainty varied considerably; consequentially the results are difficult to compare in any consistent manner. Efforts for future studies to harmonize study design and methodology, particularly towards adopting a modeling framework, using current treatment as comparator and adopting a common effectiveness measure, such as the QALY, should be made in order to produce results that are comparable and useful to a decision maker.