Abstract

Advice on how to access the best available online sources of research evidence on clinical and cost effectiveness published in three recent issues of Effectiveness Matters is reviewed.

Abstract

BACKGROUND: Type 2 diabetes is characterized by insulin resistance and the progressive loss of islet beta-cell function. Although the former is already established at diagnosis and changes little thereafter, beta-cell function continues to decline, leading to secondary failure of anti-hyperglycaemic therapies.

AIM: To develop a quantitative model of the process of beta-cell function decay over time, using trial data.

DESIGN: Re-analysis of published data.

METHODS: The results of the Belfast Diet Study were re-analysed. Assuming patients are diagnosed at different stages in the disease process, time displacement of data was used to obtain a bi-partite spline model describing loss of insulin secretion over a 6-year period.

RESULTS: The model was developed combining two phases, in which a long slow gradual loss of beta-cell function leads to a crisis in metabolic regulation, precipitating a much more rapid decay phase. This paradigm was consistent with a previous non-linear model of beta-cell mass regulation.

DISCUSSION: This model may have important implications for targeting appropriate therapy to patients in each phase: delaying or avoiding full clinical type 2 diabetes in the first phase; and preventing the development of diabetic complications in the second phase.

Abstract

No abstract available

Abstract

BACKGROUND AND AIMS: To compare the cost-effectiveness of adding rosiglitazone 8 mg versus maximal dose sulphonylurea to metformin for obese patients failing to control HbA1c on metformin monotherapy.

MATERIALS AND METHODS: DiDACT is an established economic model of the long-term complications of type 2 diabetes. The model follows a cohort of 1,000 patients (410 male and 590 female) through multiple stages of microvascular and macrovascular disease. Inpatient, outpatient, and medication costs are included. Failure of glycaemic control was defined as HbA1c = 8.0%. The cohort has BMIs of 38 and 43 kg/m2 for males and females as per 2000 NHIS data using the Center for Disease Control's definition for obesity. Population demographics were taken from National Health and Nutrition Examination Survey III. Costs and outcomes were discounted at 3% per annum.

RESULTS: For males, adding rosiglitazone was estimated to increase total quality of life years (QALYs) by 94 and increase total life years by 53.5, compared with adding sulphonylurea. For females, adding rosiglitazone was estimated to increase total QALYs by 140 and increase total life years by 62. Costs per additional QALY were $38,838 in males and $39,539 in females.

CONCLUSIONS: The cost-effectiveness of a rosiglitazone plus metformin combination is comparable with other regularly prescribed interventions (such as statins in the cardiovascular area). These results illustrate that adding rosiglitazone to metformin may lead to long-term benefits in obese patients.

Abstract

OBJECTIVE: Outcomes in healthcare technology reviews now increasingly include cost as well as effectiveness. The aim of this study is to report the findings and implications of a survey regarding the usefulness of NHS Economic Evaluation Database (NHS EED) structured abstracts within this process.
METHODS: Postal survey of lead authors of Technology Assessment Reviews (TARs) commissioned by the UK's National Institute for Clinical Excellence. The questionnaire investigated the usefulness of NHS EED regarding: search strategy, data extraction, quality assessment, and requirement for new modeling studies. Qualitative data were requested, including opinions regarding NHS EED.

RESULTS: NHS EED was used in 90% of all identified reviews (n = 46). The questionnaire response rate was 57%. The percentage of scores 3 or above, 2 or below, or N/A were, respectively: search strategy = 60%, 22%, 17%; data extraction = 26%, 26%, 48%; quality assessment = 30%, 22%, 48%; requirement for new modeling studies = 22%, 26%, 52%. The results were expanded upon in the qualitative data from the respondents.

CONCLUSIONS: Where several economic evaluations had been published NHS EED was utilized and valued as an independent source, and was highly useful to non-economists. However, those undertaking TARs also used confidential data from company submissions and cost data for studies not critiqued on NHS EED. More standardization and use of quality checklists in reviews of economic studies is clearly needed. The findings will help in developing and improving NHS EED in its role of providing health outcomes and economic evidence in TARs

Abstract

BACKGROUND AND AIMS: Current guidelines in Germany recommend use of Rosiglitazone (RSG) in combination with Metformin for treatment of obese patients with Type 2 diabetes when Metformin monotherapy is no longer effective in maintaining glycaemic control. We assess the cost-effectiveness
of this strategy compared to combination therapy with Glibenclamide.

MATERIALS AND METHODS: DiDACT, an established long-term economic model of Type 2 diabetes, was adapted for clinical practice and health care financing rules in Germany. The model was calibrated using CODE-2® study data and national statistics. The perspective is that of the sickness
funds, and includes all hospital care, physician consultations, medications (incl. test strips), rehabilitation, physiotherapy, foot care and sick leave. The model was used to simulate treatment histories for a mixed incident cohort of 1000 obese patients (BMI=30). Following failure of glycaemic control
with Metformin alone, combination therapy adding RSG was compared to adding Glibenclamide. The threshold for switching therapies was 7% HbA1c. In line with national guidelines, costs were discounted at 5% pa.

RESULTS: The model predicts that adding RSG (4mg titrated to 8mg daily) to Metformin produces better glycaemic control in most patients, and extends viability of combination therapy by at least 7 years before requiring insulin. The extra life-years estimated in a mixed cohort of newly diagnosed patients are conservative as some progress too rapidly to insulin to be eligible for combination therapy. Additional gains in QALYs arise from fewer or delayed complications, and improved quality of life while insulin treatment is avoided. Net cost increases are modest since additional costs of RSG are partly offset by savings from delaying insulin therapy.

CONCLUSIONS: Use of RSG in combination with Metformin to improve glycaemic control and delay use of insulin is highly cost-effective in Germany when compared to Metformin + Glibenclamide.

Abstract

INTRODUCTION: Influenza is associated with illnesses such as pneumonia and other respiratory conditions and in severe cases leads to death. The prevalence of these illnesses and deaths fluctuates with the seasons during the year, even in the absence of influenza. Although many studies have focussed on mortality associated with influenza epidemics, and some have examined hospitalizations in elderly patients, there are very few studies that have examined the effect of influenza epidemics on adults or children. This study seeks to determine the association between general practitioner (GP) consultations for influenza-like illnesses and hospital admissions of adults and children associated with influenza epidemics.

METHODS: Structural Time Series Models with stochastic trend and seasonal components were developed for two age groups (children aged 0-15 years, and adults aged 16-50 years). Data from the Swiss Sentinel Surveillance Network on GP consultation rates for influenza-like illnesses, and data from Swiss hospital admissions, were obtained for the period 1987-1996. The explanatory variables (i.e., the percentage of GP consultations for influenza-like illnesses and a 1-week lag of this variable) were modeled against hospital admission rates for pneumonia and influenza and other respiratory conditions. Excess hospitalizations were calculated as the difference between predicted hospital admissions during influenza epidemics and expected hospital admissions in the absence of influenza epidemics.

RESULTS: In these two age groups, there was an annual average of 1452 (range: 1000-1700) hospital admissions directly associated with influenza epidemics. Excess admission rates were substantially higher in children (pneumonia and influenza: 4.77 per 10 000 children per year, and other respiratory conditions: 2.29 per 10 000 children per year) compared with adults (pneumonia and influenza: 0.86 per 10 000 adults per year and other respiratory conditions: 0.68 per 10 000 adults per year). The models explained 56-84% of the variation in hospital admissions. The seasonal patterns were stable over the 10 years modeled and the variances of the trends were small.

CONCLUSION: The structural time series models is an ideal approach to model influenza-related hospitalizations as the models capture trends, seasonal variation, and the association with exogenous factors.