Acarbose in addition to existing treatments in patients with type 2 diabetes: health economic analysis in a German setting

OBJECTIVE

A recent retrospective meta-analysis of cardiovascular events from long-term studies with acarbose in type 2 diabetes showed that treatment was associated with a significant reduction in the risk of cardiovascular events, supporting the hypothesis that postprandial hyperglycemia is a risk factor for cardiovascular disease. The aim of the present study was to assess the cost-effectiveness of acarbose, given in addition to existing treatments, in type 2 diabetes patients, based on these findings, in the German setting.

METHODS

The CORE Diabetes Model, a published, validated computer simulation model, was used to project long-term clinical and cost outcomes in type 2 diabetes patients receiving acarbose or placebo in addition to existing treatments. Direct costs were retrieved from published sources and projected over patient lifetimes from a third party payer perspective. Costs and clinical benefits were discounted at 5% annually. Extensive sensitivity analyses were performed.

RESULTS

Acarbose treatment was associated with improvements in discounted life expectancy (0.21 years) and quality-adjusted life expectancy (QALE) (0.19 QALYs) but was on average marginally more expensive than treatment in the placebo arm (euro135 per patient). This led to incremental cost-effectiveness ratios of euro633 per life year and euro692 per quality-adjusted life year gained. Sensitivity analysis showed that these findings were robust under variation in a range of assumptions.

CONCLUSIONS

Addition of acarbose to existing treatment was associated with improvements in life expectancy and quality-adjusted life expectancy, and provides excellent value for money over patient lifetimes in the German setting.

Health economic implications of irbesartan plus conventional antihypertensive medications versus conventional blood pressure control alone in patients with type 2 diabetes, hypertension, and renal disease in Switzerland

OBJECTIVES

The aim of this health economic modelling study was to investigate the effect of irbesartan combined with conventional antihypertensive medications compared to conventional antihypertensive therapy alone on the progression of nephropathy in patients with hypertension, type 2 diabetes and microalbuminuria in a Swiss setting.

METHODS

In simulated patients with hypertension and type 2 diabetes, treatment of microalbuminuria with irbesartan 300 mg daily plus conventional antihypertensive medications was compared to a control regimen (conventional medications excluding angiotensin converting enzyme inhibitors, other angiotensin-2-receptor antagonist and dihydropyridine calcium channel blockers). Progression from microalbuminuria to nephropathy, doubling of serum creatinine, ESRD, and all-cause mortality was simulated over a 25-year time horizon using a published Markov model adapted to a Swiss setting. Transition probabilities were based on the Irbesartan in Reduction of Microalbuminuria-2 Study, Irbesartan in Diabetic Nephropathy Trial and other sources. Costs and clinical outcomes were discounted at 5% annually according to Swiss guidelines, and a third party payer perspective was taken.

RESULTS

Treatment with irbesartan was projected to improve mean life expectancy by 0.57 years compared to conventional antihypertension treatment (undiscounted 1.22 years). Irbesartan treatment was associated with cost savings of CHF 21,488 per patient over the 25-year time horizon. Sensitivity analysis showed that irbesartan therapy remained dominant to conventional antihypertension treatment over a range of plausible assumptions.

CONCLUSIONS

Addition of irbesartan to conventional antihypertension therapy was projected to improve life expectancy and reduce costs in hypertensive patients with type 2 diabetes and microalbuminuria in a Swiss setting.

Left ventricular hypertrophy determined by Sokolow–Lyon criteria: a different predictor in women than in men?

The clinical usefulness of the Sokolow-Lyon voltage criteria in the assessment of electrocardiographic left ventricular hypertrophy (ECG LVH) is addressed. We prospectively studied 3,338 women and 3,330 men referred with hypertension, with an average follow-up of 11.2 years. The voltage amplitude sum SV1+max (RV5 or RV6) was calculated and ECG LVH was defined as a sum >or=3.5 mV. We adjusted survival for age, treatment status before presentation and a previous myocardial infarction or cerebrovascular accident. The risk of stroke, coronary heart disease (CHD) and cardiovascular disease (CVD) mortality increased significantly for each quantitative 0.1 mV increase in baseline electrocardiogram (ECG) voltage, in women within the range of 1.6-3.9% and in men 1.4-3.0%. After further adjustments for race, body mass index, smoking and systolic blood pressure, increasing voltage independently predicted CVD mortality in both men and women. In women, both increasing voltage and the presence of left ventricular hypertrophy (LVH) were predictors of stroke mortality, whereas in men this risk was attenuated. In men, the adjusted association between increasing voltage and CHD mortality tended to be stronger than in women. The use of different thresholds for the two genders made little difference. For stroke and CHD mortality, the population attributable fractions associated with LVH were 15.2 and 5.4% in women and 12.8 and 8.5% in men, respectively. In conclusion, the greater the baseline ECG voltage sum, the greater the associated CVD mortality risk. Women tended to have a high risk of stroke mortality owing to LVH despite adjustments.

Cost-utility analysis in a UK setting of self-monitoring of blood glucose in patients with type 2 diabetes

BACKGROUND

Self-monitoring of blood glucose (SMBG) in type 2 diabetes patients has been shown in meta-analyses of randomized trials to improve HbA(1c) by approximately 0.4% when compared to no SMBG. However, the cost of testing supplies is high, improvements in health utility due to improved glycaemic control may be possible and cost-effectiveness has not been evaluated.

METHODS

A peer-reviewed validated model projected improvements in lifetime quality-adjusted life years (QALYs), long-term costs and cost-effectiveness of SMBG versus no SMBG. Markov/Monte Carlo modelling simulated the progression of complications (cardiovascular, neuropathy, renal and eye disease). Transition probabilities and HbA(1c)-dependent adjustments came from the United Kingdom Prospective Diabetes Study (UKPDS) and other major studies. Effects of SMBG on HbA(1c) came from clinical studies, meta-analyses and population studies, but can only be considered 'moderate' levels of evidence. Costs of complications were retrieved from published sources. Direct costs of diabetes complications and SMBG were projected over patient lifetimes from a UK National Health Service perspective. Outcomes were discounted at 3.5% annually. Extensive sensitivity analyses were performed.

RESULTS

Depending on the type of diabetes treatment (diet and exercise/oral medications/insulin), improvements in glycaemic control with SMBG improved discounted QALYs anywhere from 0.165 to 0.255 years, with increased total costs of 1013 pounds sterlings- 2564 pounds sterlings/patient, giving incremental cost-effectiveness ratios of 4508 pounds sterlings: 15,515 pounds sterlings/QALY gained, well within current UK willingness-to-pay limits. Results were robust under a wide range of plausible assumptions.

CONCLUSIONS

Based on the moderate level of clinical evidence available to date, improvements in glycaemic control with interventions, including SMBG, can improve patient outcomes, with acceptable cost-effectiveness ratios in the UK setting.

[Health economic consequences of the use of irbesartan in patients with type 2 diabetes, hypertension and nephropathy in Switzerland]

The irbesartan in Diabetic Nephropathy Trial (IDNT) demonstrated that treatment of patients with type 2 diabetes, hypertension and nephropathy with irbesartan resulted in a 20% relative reduction of the composite endpoint of doubling serum creatinine, end-stage renal disease or death as compared with amlodipine and placebo (antihypertensive standard therapy). The objective of this study was to investigate the long-term health economic consequences of this treatment strategy in a Swiss health care setting. This analysis used a Markov model to simulate the progression of nephropathy, life-years and treatment costs over ten years for each of the three treatment options. In additon, sensitivity analyses were performed. Treatment with irbesartan will save CHF 22681/patient as compared with amlodipine and CHF 13847 as compared with standard therapy.

Counting the costs of overweight and obesity: modeling clinical and cost outcomes

OBJECTIVE

To quantify changes in clinical and cost outcomes associated with increasing levels of body mass index (BMI) in a US setting.

RESEARCH METHODS AND PROCEDURES

A semi-Markov model was developed to project and compare life expectancy (LE), quality-adjusted life expectancy (QALE) and direct medical costs associated with distinct levels of BMI in simulated adult cohorts over a lifetime horizon. Cohort definitions included age (20-65 years), gender, race, and BMI (24-45 kg m(-2)). Cohorts were exclusively male or female and either Caucasian or African-American. Mortality rates were adjusted according to these factors using published data. BMI progression over time was modeled. BMI-dependent US direct medical costs were derived from published sources and inflated to year 2004 values. A third party reimbursement perspective was taken. QALE and costs were discounted at 3% per annum.

RESULTS

In young Caucasian cohorts LE decreased as BMI increased. However, in older Caucasian cohorts the BMI associated with greatest longevity was higher than 25 kg m(-2). A similar pattern was observed in young adult African-American cohorts. A survival paradox was projected in older African-American cohorts, with some BMI levels in the obese category associated with greatest longevity. QALE in all four race/gender cohorts followed similar patterns to LE. Sensitivity analyses demonstrated that simulating BMI progression over time had an important impact on results. Direct costs in all four cohorts increased with BMI, with a few exceptions.

CONCLUSIONS

Optimal BMI, in terms of longevity, varied between race/gender cohorts and within these cohorts, according to age, contributing to the debate over what BMI level or distribution should be considered ideal in terms of mortality risk. Simulating BMI progression over time had a substantial impact on health outcomes and should be modeled in future health economic analyses of overweight and obesity.

Cost-effectiveness of basal insulin from a US health system perspective: comparative analyses of detemir, glargine, and NPH

The purpose of this study was to compare in clinical and economic terms the long-acting insulin analogue detemir with intermediate-acting Neutral Protamine Hagedorn (NPH) insulin and with long-acting insulin glargine. Investigators used the validated Center for Outcomes Research (CORE) Diabetes Model to project clinical and cost outcomes over a 35-year base case time horizon; outcome data were extracted directly from randomized, controlled trials designed to compare detemir with NPH and with insulin glargine. Modeled patient characteristics were derived from corresponding trials, and simulations incorporated published quality-of-life utilities with cost data obtained from a Medicare perspective. Detemir, when compared with NPH, increased quality-adjusted life expectancy by 0.698 quality-adjusted life-years (QALYs). Lifetime direct medical costs were increased by 10,451 dollars per patient, although indirect costs were reduced by 4688 dollars. On the basis of direct costs, the cost per QALY gained with detemir was 14,974 dollars. In comparison with glargine, detemir increased quality-adjusted life expectancy by 0.063 QALYs, reduced direct medical costs by 2072 dollars per patient, and decreased indirect costs by 3103 dollars (dominant). Reductions in diabetes-related comorbidities were also associated with detemir in both instances, most notably in the complications of retinopathy and nephropathy. Relative reductions in rates of complications were greatest in the comparison of detemir with NPH. Results were most sensitive to variation in hemoglobin A1c (HbA1c) levels. However, variation among any of the key assumptions, including HbA1c, did not alter the relative results. Detemir represents an attractive clinical and economic intervention in the US health care setting compared with both NPH insulin and insulin glargine.

Towards creation of iron nanodots using metastable atom lithography

Iron structures with dimensions of the order of the minimum domain size (∼50 nm at room temperature) may provide us with a new high-density data storage method. Limitations have been observed in existing depositional atom lithography schemes for producing these structures. We present a proof-in-principle experiment using an alternative scheme based upon direct exposure metastable neon-atom lithography. Iron structures with dimensions of the order of 7.5 µm are produced by this method. Extension of this work to the application of standing-wave atom lithography and laser cooling flux enhancement techniques is discussed as a method for reducing dimensions to a size equating to a dot array density of around 0.1 Gbit mm(-2).

Cost-consequence analysis in a French setting of screening and optimal treatment of nephropathy in hypertensive patients with type 2 diabetes

AIM

Forty percent of hypertensive type 2 diabetes patients develop nephropathy (microalbuminuria/overt nephropathy), indicating end organ damage, increased risk of cardiovascular disease (CVD), and death. In France, screening rates and nephropathy treatment are suboptimal. We assessed the health economic impact of nephropathy screening in hypertensive patients with type 2 diabetes followed by optimal antihypertensive/nephroprotective therapy in those who have nephropathy in France.

METHODS

A Markov/Monte Carlo model simulated lifetime impacts of screening for albuminuria (microalbuminuria/overt nephropathy) using semi-quantitative urine dipsticks in a primary care setting, and subsequent addition of irbesartan 300 mg to conventional therapy in hypertensive type 2 diabetes patients identified as having nephropathy. Progression from no renal disease to end-stage renal disease (ESRD) was simulated. Probabilities, utilities and costs of CVD events, medications and ESRD treatment came from published sources. Cumulative incidence of ESRD, life expectancy, quality-adjusted life years (QALYs) and direct costs were projected. Second-order Monte Carlo simulation accounted for uncertainty in multiple parameters. Costs and QALYs were discounted at 3% annually.

RESULTS

Screening and optimized treatment led to a 42% reduction in the cumulative incidence of ESRD from 10.1 +/- 9.9% without screening to 5.8 +/- 5.7%, improvements in life expectancy of 0.38 +/- 0.59 years, improvements of 0.29 +/- 0.32 QALYs, and decreased costs of Euro 4,812 +/- 7,882/patient over 25 years. Sensitivity analysis showed that the results were robust. Screening was most beneficial when performed in younger patients.

CONCLUSION

In hypertensive patients with type 2 diabetes, screening for albuminuria followed by optimal antihypertensive/nephroprotective treatment improves patient outcomes and leads to cost savings in France.

Long-term clinical and cost outcomes of treatment with biphasic insulin aspart 30/70 versus insulin glargine in insulin naïve type 2 diabetes patients: cost-effectiveness analysis in the UK setting

OBJECTIVES

To evaluate the long-term clinical and cost outcomes associated with biphasic insulin aspart 30/70 (BIAsp 30/70, premixed 30% soluble and 70% protaminated insulin aspart in one injection) compared to insulin glargine treatment in insulin-naïve type 2 diabetes patients failing oral antidiabetic agents in the UK, based on findings recently reported from the INITIATE clinical trial.

METHODS

The CORE Diabetes Model, a published, peer-reviewed and validated model of diabetes, was used to evaluate life expectancy, quality-adjusted life expectancy, cumulative incidence of complications and direct medical costs over patient lifetimes. The model simulates the range of diabetic complications and disease progression within a series of sub-models (cardiovascular disease, neuropathy, renal and eye disease) based on published data. Baseline cohort characteristics (54.5% male, mean age 52.45 years, mean diabetes duration 9 years, mean HbA(1c) 9.77%) and treatment effects were based on INITIATE. Costs were derived from published UK sources. The analysis was run over a 35-year time horizon (patient lifetime) from a third party payer perspective. Costs and clinical benefits were discounted at 3.5% per annum. Sensitivity analyses were performed.

RESULTS

BIAsp 30/70 was associated with projected improvements in discounted life expectancy (0.19 +/- 0.20 years) and quality-adjusted life expectancy (0.19 +/- 0.14 quality-adjusted life years [QALYs]), as well as a reduced incidence of retinopathy and nephropathy complications, versus glargine. Total lifetime direct costs were 1319 pounds higher with BIAsp 30/70 than with glargine leading to an incremental cost-effectiveness ratio of 6951 pounds per QALY gained.

CONCLUSIONS

This study is the first to address the long-term health economic implications of treating type 2 diabetes patients failing oral anti-diabetics with a biphasic insulin mix versus long-acting insulin. Our projections indicate that improved HbA1c levels with BIAsp 30/70 treatment are associated with improvements in life expectancy and quality-adjusted life expectancy, and that BIAsp 30/70 represents excellent value for money compared to insulin glargine in the UK.

Review of the cost of diabetes complications in Australia, Canada, France, Germany, Italy and Spain

OBJECTIVES

To provide a comprehensive source document on previously published cost data for diabetic complications in Australia, Canada, France, Germany, Italy and Spain for use in a peer-reviewed, validated diabetes model.

METHODS

A search for published cost of diabetes complications data was performed in peer-reviewed journals listed in PubMed and health economic conference proceedings from 1994 to March 2005. Where country specific data were not available, we referred to government websites and local cost experts. All costs were inflated to 2003 Euros (E). Major complication costs are presented.

RESULTS

First year costs of non-fatal myocardial infarction varied between E19277 in Spain and E12292 in Australia. In subsequent years of treatment, this range was E1226 (France) to E203 (Australia). Angina costs were similar across all four countries: E1716 in Australia; E2218 in Canada; E2613 in France; E3342 in Germany; E2297 in Italy; and E2207 in Spain. Event costs of non-fatal stroke were higher in Canada (E23173) than in other countries (Australia E13443; France E11754; Germany E19399; Italy E6583; Spain E4638). Event costs of end-stage renal disease varied depending on the type of dialysis: in Australia (E17188-27552); Canada (E33811-58159); France (E24608-56487); Germany (E46296-68175); Italy (E43075-56717); and Spain (E28370-32706). Lower extremity amputation costs were: E18547 (Australia); E17130 (Canada); E31998 (France); E22096 (Germany); E10177 (Italy); and E14787 (Spain).

CONCLUSIONS

Overall, our search showed costs are well documented in Australia, Canada, France and Germany, but revealed a paucity of data for Spain and Italy. Spanish costs, collected by contacting local experts and from government reports, generally appeared to be lower for treating cardiovascular complications than in other countries. Italian costs reported in the literature were primarily hospitalization costs derived from diagnosis-related groups, and therefore likely to misrepresent the cost of specific complications. Additional research is required to document complication costs in Spain and Italy. Australian and German values were collected primarily by referring to diagnostic related group (DRG) tariffs and, as a result, there may be a need for future economic evaluations measuring the accuracy of the costs and resource utilization in the reported values. These cost data are essential to create models of diabetes that are able to accurately simulate the cumulative costs associated with the progression of the disease and its complications.

Health-economic comparison of continuous subcutaneous insulin infusion with multiple daily injection for the treatment of Type 1 diabetes in the UK

OBJECTIVES

The aim of this study was to project the long-term costs and outcomes of continuous subcutaneous insulin infusion (CSII) compared with multiple daily injections (MDI) in patients with Type 1 diabetes in the UK.

METHODS

The CORE Diabetes Model is a peer-reviewed, validated model which employs standard Markov/Monte Carlo simulation techniques to describe the long-term incidence and progression of diabetes-related complications. It was used to simulate disease progression in a cohort of patients with baseline characteristics taken from published UK studies (mean age 26 years, duration of diabetes 12 years, mean HbA1c 8.68%). Direct costs for 2003 were calculated from a third-party payer perspective. Discount rates of 3.0% per annum were applied to costs and clinical outcomes.

RESULTS

Treatment with CSII was associated with an improvement in mean quality adjusted life expectancy (QALE) of 0.76 +/- 0.19 years compared with MDI (12.03 +/- 0.15 vs. 11.27 +/- 0.14 years). Mean direct lifetime costs were pounds 19,407 +/- 1727 higher with CSII treatment compared with MDI (pounds 80,511 +/- 1257 vs. pounds 61,104 +/- 1249). This produced an incremental cost-effectiveness ratio (ICER) of pounds 25,648 per quality-adjusted life year (QALY) gained with CSII vs. MDI. The results were most sensitive to variation in hypoglycaemia rates and altering improvements in HbA1c associated with CSII therapy compared with MDI.

CONCLUSIONS

Improvements in glycaemic control associated with CSII over MDI led to improved QALE owing to reduced incidence of diabetes-related complications. CSII was associated with an ICER of pounds 25,648 per QALY gained vs. MDI, representing good value for money by current standards in the UK.

Transiently elevated diastolic blood pressure is associated with a gender-dependent effect on cardiovascular risk

We assessed the morbidity and mortality of subjects with transiently elevated diastolic pressure in the General Practice Hypertension Study Group (GPHSG) population. A total of 23 578 patients (aged 18-65 years) from seven UK general practices were screened in 1974 for a diastolic blood pressure (DBP4) of > or = 90 mmHg. Two further readings of DBP4 determined hypertensive (either DBP4 > or = 90 mmHg) or transient hypertensive (both DBP4 < 90 mmHg) status. Transients (n = 850) were matched with normotensive controls (n = 824) and risk ratios calculated over a mean follow-up of 18.7 years. Rescreening was conducted in six of the practices (n = 20 942) after 7.7 years. Male transients had a higher relative hazard for cardiovascular mortality than controls (11.8%, 8.6%, adjusted relative hazard 1.59, P = 0.056). Female transients had a lower relative hazard for cardiovascular mortality than controls (3.6%, 5.4%, adjusted relative hazard 0.39, P = 0.018). In all, 422 patients with transient hypertension were rescreened along with 367 matched controls. Significantly more transients were on antihypertensive treatment compared with their controls (odds ratio (OR) [95% CI]) for both male (4.2 [1.6-11.1]) and female patients (2.4 [1.0-5.56]) and more untreated female transients developed hypertension. Male transients had a higher rates of diabetes mellitus (adj OR = 5.1, P = 0.04) and stroke (adj OR 15.9, P = 0.03). This study has shown that transiently elevated DBP in GPHSG is associated with a significantly higher risk of later hypertension in men and women and of diabetes, stroke and cardiovascular mortality in men. Women with this condition have a significantly lower cardiovascular mortality.

Irbesartan is projected to be cost and life saving in a Spanish setting for treatment of patients with type 2 diabetes, hypertension, and microalbuminuria

OBJECTIVES

The purpose of this study was to project the cumulative incidence of end-stage renal disease (ESRD), life expectancy, and costs in a Spanish setting of treating patients with diabetes, hypertension, and microalbuminuria with either standard hypertension treatment alone or standard hypertension treatment plus irbesartan 300 mg daily.

METHODS

A peer-reviewed, published Markov model that simulated progression from microalbuminuria to nephropathy, doubling of serum creatinine, ESRD, and all-cause mortality in patients with hypertension, type 2 diabetes, and microalbuminuria was adapted to a Spanish setting. Two strategies were compared: (1) irbesartan versus (2) standard hypertension care with comparable blood pressure control; both began in diabetic hypertensive subjects with microalbuminuria. Cumulative incidence of ESRD, costs, and life expectancy were projected for a hypothetical cohort of 1000 subjects. Future costs and life expectancy were discounted at 3% yearly. A 25-year time horizon and third party payer perspective were used.

RESULTS

When compared to standard blood pressure control, irbesartan was projected to reduce the cumulative incidence of ESRD from (mean +/- standard deviation) 24 +/- 1% to 9 +/- 2%, save 11,082 +/- 2,996 euro, and add 1.40 +/- 0.27 life years per treated patient. The superiority of irbesartan over standard care was robust under a wide range of plausible assumptions.

CONCLUSION

Treating patients with hypertension, microalbuminuria, and type 2 diabetes with irbesartan was projected to reduce the incidence of ESRD, extend life, and reduce costs.

A critical review of pharmacoeconomic studies of acamprosate

AIMS

This review assessed the published data on the cost-effectiveness of acamprosate for the treatment of alcohol dependence.

METHODS

Four Markov modelling studies have assessed the therapeutic benefit and economic impact of acamprosate on the treatment of alcohol dependence. These have evaluated both short-term and long-term outcomes and have used German, Belgian, and Spanish costings. A fifth prospective cohort study collected real outcomes and data on expenditure during a 1 year study follow-up period.

RESULTS

All five studies have produced consistent results, showing the use of acamprosate, which enhances abstinence rates, to reduce the total costs of treatment and thus be dominant over other rehabilitation strategies not involving pharmacotherapy. In all of the studies, the principal cost-driver is hospitalization. Although there is a short-term increase in treatment costs associated with drug acquisition, these are recovered from long-term savings attributable to reduced hospitalization and rehabilitation costs.

Treating diabetes to accepted standards of care: A 10-year projection of the estimated economic and health impact in patients with type 1 and type 2 diabetes mellitus in the United States

OBJECTIVE

The aim of this study was to investigate the health-economic impact of maintaining glycosylated hemoglobin (HbA(1c)) values in all US patients with currently uncontrolled type 1 or type 2 diabetes mellitus at the American Diabetes Association (ADA) standard of 7.0% and the American Association of Clinical Endocrinologists (AACE) target of 6.5% compared with maintenance at current population-based values.

METHODS

The CORE-Center for Outcomes Research Diabetes Model was used to predict costs and outcomes for patients with uncontrolled type 1 and type 2 diabetes who remain at established population mean HbA(1c) values in comparison with those for patients who maintain the standard value of 7.0% or the target value of 6.5%. The analysis was run from a societal perspective over a 10-year time horizon. The costs of treating complications and medication costs were retrieved from published sources. Costs and clinical outcomes were discounted at 3% per annum. Sensitivity analyses were performed on the discount rate and time horizon.

RESULTS

This analysis found that maintaining HbA(1c) at the ADA standard value of 7.0% and the AACE target value of 6.5% in patients with uncontrolled type 1 and type 2 diabetes could achieve total direct medical cost savings of nearly 35 US dollars and 50 billion US dollars , respectively, over 10 years. When indirect cost savings were included, the total savings increased to between nearly 50 billion US dollars and 72 billion US dollars for these respective HbA(1c) targets, corresponding to 4% and 6% of the total annual US health care costs of 1.3 trillion US dollars. Reduced savings were observed with a higher discount rate and shorter time horizon, but savings increased as the time horizon became longer. These cost savings must be weighed against the cost of reaching the HbA(1c) goals and the likelihood of achieving the clinical objectives.

CONCLUSIONS

Efficient targeting of financial resources toward the goal of lowering HbA(1c) in line with published guidelines could lead to financial savings in the range from nearly 35 billion US dollars to 72 billion US dollars over the next 10 years.

Cost-effectiveness of irbesartan in diabetic nephropathy: a systematic review of published studies

BACKGROUND

To review published studies on the cost-effectiveness of the use of irbesartan for treatment of advance overt nephropathy in patients with type 2 diabetes and hypertension.

METHODS

Articles were identified based on a search of the PubMed databases using the keywords 'irbesartan', 'ESRD', 'cost-effectiveness', 'nephropathy' and 'costs', and by personal communication with the authors. Only studies published in the last 10 years were included. All costs data from the cost-effectiveness studies were inflated to 2003 Euros using published governmental conversion tables.

RESULTS

Seven published studies were identified, spanning the following country settings: the US, Belgium and France, Germany, Hungary, Italy, Spain, and the UK. In each, the same pharmacoeconomic model was adapted using country-specific data to project and evaluate the clinical and cost outcomes of the treatment arms of the Irbesartan in Diabetic Nephropathy Trial (IDNT) (irbesartan, amlodipine or standard blood pressure control). Mean time to onset of ESRD was 8.23 years for irbesartan, 6.82 years for amlodipine and 6.88 years for the control (values were the same for Belgium, France, Germany, Hungary, Italy and Spain as transition probabilities for progression to ESRD were all derived from the IDNT). Mean cumulative incidence of ESRD was 36% with irbesartan, 49% with amlodipine and 45% with control treatment. Treatment with irbesartan was projected to improve life expectancy compared to both amlodipine and control in all seven published studies. Analysis of total lifetime costs showed that irbesartan treatment was cost saving compared to the other two treatment regimens, due to the associated reduction in ESRD cases. Cost savings with irbesartan became evident very early; after 2-3 years of treatment in most settings.

CONCLUSIONS

Modelling studies based on the IDNT published to date suggest that irbesartan treatment in patients with type 2 diabetes, hypertension and advanced nephropathy is both life- and cost-saving compared to amlodipine or control.

An economic evaluation of the Irbesartan in Diabetic Nephropathy Trial (IDNT) in a UK setting

There are substantial healthcare costs associated with the provision of renal replacement therapy. Patients with diabetes mellitus are the largest and fastest growing group developing end-stage renal disease (ESRD) in the United Kingdom (UK). Treatment leading to a slowing of progression to ESRD in diabetic patients could lead to considerable cost savings. Using treatment-specific probabilities derived from the Irbesartan in Diabetic Nephropathy Trial (IDNT), the cost effectiveness of treating patients with hypertension, type II diabetes and nephropathy with irbesartan, amlodipine or control was calculated using a Markov model. UK-specific ESRD-related data were retrieved from published sources to reflect local management practices, ESRD outcomes and costs. Mean 10-year costs and changes in life expectancy due to ESRD delayed or avoided were calculated. Future costs and clinical benefits were discounted at 6.0 and 1.5% per annum and extensive sensitivity analyses were performed. Delay in the onset of ESRD with irbesartan led to cost savings of pound sterling 5125 and pound sterling 2919/patient and improvements in projected discounted life expectancy of 0.07 and 0.21 years over 10 years vs amlodipine and control, respectively. The costs of treatment of ESRD were the main contributor to the total costs. The cost of trial medications had only a minor impact. These results were robust in a wide range of plausible assumptions. Given that the IDNT efficacy results could be translated to a UK setting, treating patients with hypertension, type II diabetes and overt nephropathy with irbesartan was cost saving over a 10-year period compared to amlodipine and control.

Overview of costs of stroke from published, incidence-based studies spanning 16 industrialized countries

OBJECTIVE

The aim of this review is to summarize published data (based on a search of Medline sources, 1993-October 2003) from the last 10 years on the costs of stroke. With the recent encouraging evidence of interventions that reduce the incidence of stroke, the primary focus is on incidence-based cost of stroke studies to identify important factors for future cost-effectiveness analyses on stroke interventions.

FINDINGS

Lifetime costs per patient were in the range USD 11 787 for 'unclassified' stroke in Australia to USD 3035671 in stroke patients with untreated non-rheumatic atrial fibrillation in a UK setting (costs inflated to 2003 values). For the lifetime costs of ischemic stroke only, the range narrowed to USD 41257 in Australia and USD 104629 in the UK. These data confirm that stroke management is associated with a vast economic burden. No correlation of lifetime cost of stroke with specific cost components or time horizon was identified. The cost of stroke is influenced by severity (more severe strokes cost more due to extended hospitalization), age (costs were greater in younger stroke patients) and gender (direct costs were greater for women, but indirect costs were greater in men).

CONCLUSION

Conducting research according to methodological consensus would markedly improve the quality of data from future studies of stroke and support identification of the main cost drivers in different country-specific settings.

Cost-effectiveness of detemir-based basal/bolus therapy versus NPH-based basal/bolus therapy for type 1 diabetes in a UK setting: an economic analysis based on meta-analysis results of four clinical trials

BACKGROUND

A meta-analysis of results from four clinical trials in type 1 diabetes patients showed that insulin detemir (IDet)-based basal/bolus treatment of type 1 diabetes led to improved HbA1c (0.15%-points lower), reduced risk of major hypoglycaemic events (by 2%) and reduction in body mass index (BMI) (0.26 kg/m2) compared to protamine Hagedorn human (NPH) insulin-based basal/bolus therapy in type 1 patients.

METHODS

A published, validated, peer-reviewed Markov simulation model (the CORE Diabetes Model) projected short-term results obtained from the fixed-effects (weighted average) meta-analysis to long-term incidence of complications, improvements in quality-adjusted life years (QALY), long-term costs and the cost-effectiveness for IDet combinations versus NPH combinations in type 1 diabetes patients. Probabilities of complications and HbA1c-dependent adjustments were derived from the DCCT and other studies. Costs of treating complications in the UK were retrieved from published sources. Total direct costs (complications + treatment costs) for each arm were projected over patient lifetimes from a UK National Heath Service perspective. Both costs and clinical outcomes were discounted at 3.5% annually.

RESULTS

Improved glycaemic control, decreased hypoglycaemic events and BMI with IDet-based basal/bolus therapy led to fewer diabetes-related complications, an increase in quality-adjusted life expectancy of 0.09 years, increased total lifetime costs/patient of 1707 pounds sterling and an incremental cost-effectiveness ratio of 19,285 pounds sterling per QALY gained. Results were stable under a wide range of reasonable assumptions.

CONCLUSIONS

Short-term improvements seen with IDet combinations versus NPH combinations led to decreased complications, improvements in QALYs and reductions in complication costs, which partially offset the additional costs of detemir, leading to a cost-effectiveness ratio which fell within a range considered to represent excellent value for money (< 35,000 pounds sterling/QALY gained).

Health economics studies assessing irbesartan use in patients with hypertension, type 2 diabetes, and microalbuminuria

Two studies comparing the cost-effectiveness of irbesartan to similar blood pressure control with standard antihypertensive medications (excluding angiotensin-converting enzyme inhibitors and other angiotensin receptor blockers) in treatment of patients with hypertension, type 2 diabetes, and microalbuminuria have been published to date; one in a United States setting, the other in a Spanish setting. Both studies were based on a Markov-based Monte Carlo simulation model, with the effects of irbesartan or standard blood pressure control taken from the Irbesartan Reduction of Microalbuminuria-2 (IRMA-2) and the Irbesartan in Diabetic Nephropathy Trial (IDNT) clinical trials. In both Spanish and U.S. settings, irbesartan was projected to delay the onset of end-stage renal disease (ESRD), reduce the cumulative incidence of ESRD, increase life expectancy, and reduce overall direct medical costs. Irbesartan treatment of patients with type 2 diabetes, hypertension, and microalbuminuria may lead to major improvements in long-term patient outcomes, with substantial cost savings as an added bonus to third party payers.

The CORE Diabetes Model: Projecting long-term clinical outcomes, costs and cost-effectiveness of interventions in diabetes mellitus (types 1 and 2) to support clinical and reimbursement decision-making

OBJECTIVES

We have developed an Internet-based, interactive computer model to determine the long-term health outcomes and economic consequences of implementing different treatment policies or interventions in type 1 and type 2 diabetes mellitus. The model projects outcomes for populations, taking into account baseline cohort characteristics and past history of complications, current and future diabetes management and concomitant medications, screening strategies and changes in physiological parameters over time. The development of complications, life expectancy, quality-adjusted life expectancy and total costs within populations can be calculated.

METHODS

The model is based on a series of sub-models that simulate important complications of diabetes (cardiovascular disease, eye disease, hypoglycaemia, nephropathy, neuropathy, foot ulcer, amputation, stroke, ketoacidosis, lactic acidosis and mortality). Each sub-model is a Markov model using Monte Carlo simulation incorporating time, state, time-in state, and diabetes type-dependent probabilities derived from published sources. Analyses can be performed on cohorts with type 1 or type 2 diabetes. Cohorts, defined in terms of age, gender, baseline risk factors and pre-existing complications, can be modified or new cohorts defined by the user. Economic and clinical data in the model can be edited, thus ensuring adaptability by allowing the inclusion of new data as they become available; creation of country- or provider-specific versions of the model; and allowing the investigation of new hypotheses.

CONCLUSIONS

The CORE Diabetes Model allows the calculation of long-term outcomes, based on the best data currently available. Diabetes management strategies can be compared in different patient populations in a variety of realistic clinical settings, allowing the identification of efficient diabetes management strategies.

Cost-effectiveness of early irbesartan treatment versus control (standard antihypertensive medications excluding ACE inhibitors, other angiotensin-2 receptor antagonists, and dihydropyridine calcium channel blockers) or late irbesartan treatment in patients with type 2 diabetes, hypertension, and renal disease

OBJECTIVE

The aim of this study was to determine the most cost-effective time point for initiation of irbesartan treatment in hypertensive patients with type 2 diabetes and renal disease.

RESEARCH DESIGN AND METHODS

This study was a Markov model-simulated progression from microalbuminuria to overt nephropathy, doubling of serum creatinine, end-stage renal disease, and death in hypertensive patients with type 2 diabetes. Two irbesartan strategies were created: early irbesartan 300 mg daily (initiated with microalbuminuria) and late irbesartan (initiated with overt nephropathy). These strategies were compared with control, which consisted of antihypertensive therapy with standard medications (excluding ACE inhibitors, other angiotensin-2 receptor antagonists, and dihydropyridine calcium channel blockers) with comparable blood pressure control, initiated at microalbuminuria. Transition probabilities were taken from the Irbesartan in Reduction of Microalbuminuria-2 study, Irbesartan in Diabetic Nephropathy Trial, and other published sources. Costs and life expectancy, discounted at 3% yearly, were projected over 25 years for 1,000 simulated patients using a third-party payer perspective in a U.S. setting.

RESULTS

Compared with control, early and late irbesartan treatment in 1,000 patients were projected to save (mean +/- SD) 11.9 +/- 3.3 million dollars and 3.3 +/- 2.7 million dollars, respectively. Early use of irbesartan added 1,550 +/- 270 undiscounted life-years (discounted 960 +/- 180), whereas late irbesartan added 71 +/- 40 life-years (discounted 48 +/- 27) in 1,000 patients. Early irbesartan treatment was superior under a wide-range of plausible assumptions.

CONCLUSIONS

Early irbesartan treatment was projected to improve life expectancy and reduce costs in hypertensive patients with type 2 diabetes and microalbuminuria. Later use of irbesartan in overt nephropathy is also superior to standard care, but irbesartan should be started earlier and continued long term.

Impact of changes in HbA1c, lipids and blood pressure on long-term outcomes in type 2 diabetes patients: an analysis using the CORE Diabetes Model

OBJECTIVES

Various factors influence the risk of complications in type 2 diabetes patients. The isolated impact of single risk factors on long-term outcomes is unclear. The aim of this study was to calculate the projected effects on life expectancy (LE), quality-adjusted LE (QALE) and total costs of complications (TC) of 10% improvements in baseline levels of either total cholesterol (T-CHOL), high-density lipoprotein cholesterol (HDL), systolic blood pressure (SBP), glycosylated haemoglobin (HbA1c), and all four parameters combined.

METHODS

A cohort of newly diagnosed patients (baseline age 52 years, HbA1c 9.1%, SBP 137 mmHg, T-CHOL 212 mg/dL, and HDL 39 mg/dL) was defined. The CORE Diabetes Model was used to simulate LE, QALE and TC (US third-party payer perspective discounted at 3% annually) over patients' lifetimes, assuming no change in risk factors, an isolated 10% improvement in each parameter, or a 10% improvement in all parameters simultaneously.

RESULTS

Improved HbA1c led to increases in LE and QALE of 1.00 and 0.81 years respectively, and decreased TC of (US) 10,800 dollars/patient. Improved SBP led to improvements in LE and QALE of 0.67 and 0.55 years respectively and decreased TC of 7,049 dollars. Decreased T-CHOL led to improvements in LE and QALE of 0.29 and 0.20 years, respectively, and increased TC of 1,923 dollars. Increased HDL led to improvements in LE and QALE of 0.28 and 0.18 years respectively, and increased TC of 2,162 dollars. Simultaneous improvements in all parameters led to projected improvements in LE and QALE of 2.17 and 1.72 years respectively, and decreased TC of 14,533 dollars.

CONCLUSIONS

Combined improvements in HbA1c, lipid levels and SBP produced the greatest benefits in terms of LE, QALE and TC. A 10% improvement in HbA1c had the greatest impact on these three outcomes.

Comparing the long-term cost-effectiveness of repaglinide plus metformin versus nateglinide plus metformin in type 2 diabetes patients with inadequate glycaemic control: an application of the CORE Diabetes Model in type 2 diabetes

OBJECTIVES

As an example application of the CORE Diabetes Model in type 2 diabetes, we simulated the cost-effectiveness of repaglinide/metformin combination therapy versus nateglinide/metformin for treatment of individuals with type 2 diabetes with an inadequate response to sulphonylurea, metformin, or fixed dose glyburide/metformin.

METHODS

The CORE Diabetes Model was used to simulate long-term outcomes for a cohort of individuals with type 2 diabetes treated with either repaglinide/metformin or nateglinide/metformin. HbA1c changes for each regimen were taken from a comparative study. At the end of the study, changes in HbA1c from baseline were -1.28% points and -0.67% points for repaglinide/metformin and nateglinide/metformin, respectively. Median final doses were 5.0 mg/day for repaglinide, 360 mg/day for nateglinide and 2000 mg/day metformin in each treatment arm. Costs were calculated as the annual costs for drugs plus costs of complications (US Medicare perspective) over a 30-year period. Life expectancy (LE) and quality-adjusted life expectancy (QALE) were calculated. Outcomes and costs were discounted at 3% annually.

RESULTS

With repaglinide/metformin, improved glycaemic control led to projected decreases in complication rates, improvement of LE and QALE by 0.15 and 0.14 years respectively, and total cost savings of 3,662 dollars/person over the 30-year period. Repaglinide/metformin had a 96% probability that the incremental costs per quality-adjusted life year gained would be 20,000 dollars or less, and a 66% probability that repaglinide/metformin would be cost-saving compared to nateglinide/metformin. Sensitivity analyses supported the validity and reliability of the results.

CONCLUSIONS

In the health economic context, repaglinide/metformin combination was dominant to nateglinide/metformin. The CORE Diabetes Model is a tool to help third-party reimbursement payers identify treatments for type 2 diabetes that are good value for money.

What impact would pancreatic beta-cell preservation have on life expectancy, quality-adjusted life expectancy and costs of complications in patients with type 2 diabetes? A projection using the CORE Diabetes Model

OBJECTIVE

Type 2 diabetes is characterised by progressive failure of pancreatic beta-cell function against a background of insulin resistance. Multifactorial interventions, including intensive glycaemic and blood pressure control, reduce the risk of onset and progression of complications. However, current management of type 2 diabetes focuses on treatment of signs and symptoms of disease instead of targeting underlying causes. A number of newer pharmacological interventions, including thiazolidinediones and glucagon-like peptides, have shown early promise in preserving pancreatic beta-cell function. The aim of this study was to investigate the impact of stabilising beta-cell function on long-term outcomes in patients with type 2 diabetes.

METHODS

The CORE Diabetes Model was used to project life expectancy (LE), quality-adjusted LE (QALE) and total lifetime complication costs (TC) for a cohort of newly-diagnosed patients with type 2 diabetes, either with a typical increase of HbA1c over time as observed in the UKPDS, or assuming stabilisation of HbA1c after diagnosis with a hypothetical new treatment, representing beta-cell function stabilisation. Costs due to diabetes-related complications (from a US third-party payer perspective), were discounted at 3% annually. Both non-discounted and discounted (at 3% annually) LE and QALE were calculated. Sensitivity analyses were performed to test the robustness of results.

RESULTS

Over a time period of 50 years, in a cohort with no increase of HbA1c over time, LE and QALE were improved by mean (SD) 1.02 (0.36) and 0.96 (0.25) years, and total costs of complications were reduced by 6,377 dollars (2,568) per patient compared to the cohort with a typical increase in HbA1c over time. Results were robust under a wide range of plausible assumptions.

CONCLUSIONS

New interventions that stabilise pancreatic betacell function may have an important impact on length and quality of life, and lead to reduced costs of complications in patients with type 2 diabetes.

Deleterious effects of increased body weight associated with intensive insulin therapy for type 1 diabetes: increased blood pressure and worsened lipid profile partially negate improvements in life expectancy

OBJECTIVE

Weight gain is an unwanted side effect of improved glycaemic control in type 1 diabetes, associated with increased blood pressure (BP) and worsening lipid profiles. While improved glycaemic control per se should improve long-term patient outcomes, increases in BP and worsening lipid profiles may counteract these benefits. The aim of this modelling study was to assess whether the increased body weight and associated worsening of lipid profile and blood pressure would negate the improvements in glycaemic control seen with intensive therapy in patients with type 1 diabetes.

METHODS

A validated diabetes model projected life expectancy (LE), quality-adjusted LE (QALE) and total lifetime costs of complications in type 1 diabetes cohorts with the characteristics of patients from the Diabetes Control and Complications Trial (DCCT). The following four cohorts (A-D) were created based on increased body weight under either conventional or intensive therapy: A) conventional glycaemic control in the subgroup with lowest weight-gain quartile after 6.5 years (HbA1c increased by 11% from baseline); B) conventional control in the highest weight-gain quartile (no change in HbA1c from baseline); C) intensive control in the lowest quartile of weight gain (with 16.1% decrease in HbA1c, but no increase in weight or associated BP, and improved lipid profile); D) intensive control in the highest quartile of weight gain (with 21% decrease in HbA1c, increased systolic BP of 6 mmHg, and worsened lipid profile). Data were derived from DCCT and other published sources.

RESULTS

Intensive control, even with weight gain, led to major improvements in LE and QALE, and reduction in costs of complications versus conventional therapy. Intensive therapy with no weight increase led to a higher LE (increased by 0.57 years) and higher QALE (increased by 0.28 years) and lower costs of complications (reduced by 523 dollars/patient), compared to intensive therapy with the highest quartile of weight gain.

CONCLUSIONS

Concerns about weight gain should not deter intensive insulin therapy. However, the value of improving glycaemic control without increasing body weight (and associated increased BP and worsening of lipid profile) has been confirmed.

Validation of the CORE Diabetes Model against epidemiological and clinical studies

OBJECTIVES

The aim of this study was to assess the validity of the CORE Diabetes Model by comparing results from model simulations with observed outcomes from published epidemiological and clinical studies in type 1 and type 2 diabetes.

METHODS

A total of 66 second- (internal) and third- (external) order validation analyses were performed across a range of complications and outcomes simulated by the CORE Diabetes Model (amputation, cataract, hypoglycaemia, ketoacidosis, macular oedema, myocardial infarction, nephropathy, neuropathy, retinopathy, stroke and mortality). Published studies were reproduced in the model by recreating cohorts in terms of demographics, baseline risk factors and complications, treatment patterns and patient management strategies, and simulating the progress of the cohort to an equivalent time horizon.

RESULTS

Correlation analysis on results from 66 validation simulations produced an R2 value of 0.9224 (perfect fit = 1). A correlation plot of published study data versus values simulated by the CORE Diabetes Model had a trend line with a gradient of 1.0187 (perfect fit = 1). Validation analyses in type 1 and type 2 diabetes were associated with R2 values of 0.9778 and 0.8861 respectively. Correlation of second-order validation analyses (model predictions versus observed outcomes in studies used to construct the model) produced an R2 value of 0.9574, and the value for third-order analyses (model predictions versus observed outcomes in studies not used to construct the model) was 0.9023.

CONCLUSIONS

The CORE Diabetes Model provides an accurate representation of patient outcomes when compared to 66 studies of diabetes and its complications. Model flexibility ensures it can be used to compare diabetes management strategies in different cohorts across a variety of clinical settings.

Intensive lifestyle changes or metformin in patients with impaired glucose tolerance: Modeling the long-term health economic implications of the diabetes prevention program in Australia, France, Germany, Switzerland, and the United Kingdom

BACKGROUND

In the Diabetes Prevention Program (DPP), interventions with metformin (plus standard lifestyle advice) or intensive lifestyle changes (ILC) reduced the risk of developing type 2 diabetes mellitus (DM) by 31% and 58%, respectively, versus control (standard lifestyle advice only) in patients with impaired glucose tolerance (IGT).

OBJECTIVE

The goal of this study was to establish whether implementing the active treatments used in the DPP would be cost-effective in Australia, France, Germany, Switzerland, and the United Kingdom.

METHODS

A Markov model simulated 3 states-IGT, type 2 DM, and deceased-using probabilities from the DPP and published data. Country-specific direct costs were used throughout.

RESULTS

Assuming only within-trial effects and costs of interventions, both metformin and ILC improved life expectancy versus control. Mean improvements in nondiscounted life expectancy were 0.11 and 0.22 years for metformin and ILC, respectively. Both interventions were associated with cost savings versus control in all countries except the United Kingdom, where a small increase in costs was observed in both intervention arms. When a lifetime effect of interventions was assumed, incremental improvements in life expectancy were 0.35 and 0.90 years for metformin and ILC, respectively. Results were sensitive to probabilities of developing type 2 DM, the projected long-term duration of effect of interventions after the 3-year trial period, the relative risk of mortality for type 2 DM compared with IGT, and the costs of implementing the interventions.

CONCLUSIONS

Based on probabilities from the DPP and published data, in this model analysis, incorporation of the DPP interventions into clinical practice in 5 developed countries was projected to lead to an increase in DM-free years of life, improvements in life expectancy, and either cost savings or minor increases in costs compared with standard lifestyle advice in a population with IGT. Thus, financial constraints should not prevent the implementation of DM prevention programs.

Gesundheitsökonomische Aspekte der Anwendung von Irbesartan bei Patienten mit Typ-2-Diabetes, Nephropathie und Hypertonie in Deutschland

BACKGROUND AND AIMS

The "Irbesartan in Diabetic Nephropathy Trial" (IDNT), demonstrated a reduction in the combined endpoint of doubling of serum creatinine, end-stage renal disease (ESRD) or death compared to control or amlodipine arms in patients with hypertension, type 2 diabetes and overt nephropathy when treated with irbesartan. Aim of this study is to compare long-term consequences in costs and outcomes of IDNT treatment alternatives from the German health care system's perspective.

METHODS

A Markov model simulated progression from overt nephropathy to doubling of serum creatinine, end-stage renal disease, and death in patients with hypertension, type 2 diabetes and overt nephropathy for the three treatment arms. Treatment-specific probabilities were derived from IDNT. German-specific ESRD-related data were retrieved from published sources to reflect local management practices, ESRD outcomes and costs. A time horizon of 10 years was used. Delay in onset of ESRD and mean costs per patient were calculated. Future costs were discounted at 5 % per annum.

RESULTS

The cumulative incidence of ESRD after 10 years with irbesartan (36 %) is lower compared to amlodipine (49 %) or control (45 %). Irbesartan leads to cost savings of 14 424 EUR and 8 720 EUR per patient versus amlodipine or control respectively.

CONCLUSION

Treating patients with hypertension, type 2 diabetes and nephropathy using irbesartan lowers the cumulative incidence of ESRD and is cost-saving compared to amlodipine or control.

[Cost-efectiveness of Ibersartan in type II diabetic nephropathy with hypertension. A Spanish perspective]

BACKGROUND

In the Irbesartan Diabetic Nephropathy Trial (IDNT), treatment with irbesartan demonstrated 23% and 20% reductions in the combined endpoint of doubling of serum creatinine (DSC), end-stage renal disease (ESRD) or death in patients with hypertension, type 2 diabetes and overt nephropathy compared to amlodipine and control respectively. A simulation model was developed to project long-term cost consequences of the IDNT in the Spanish setting.

METHODS

A Markov model simulated progression from nephropathy to DSC, ESRD and death in patients with hypertension, type 2 diabetes and overt nephropathy. Treatment-specific probabilities were derived from IDNT. Country-specific ESRD-related data were retrieved from published sources. Delay in onset of ESRD, life expectancy and mean lifetime costs were calculated for patients with baseline age 59 years. Future costs were discounted at 6% per annum, and clinical benefits were discounted at 0% and 6% per annum. Extensive sensitivity analyses were performed.

RESULTS

Onset of ESRD was delayed with irbesartan by 1.41 and 1.35 years versus amlodipine and control respectively. When a 25-year (lifetime) horizon was considered, delay in ESRD onset led to anticipated improvements in life expectancy (discounted at 6% shown in brackets) of 0.46 (0.21) years versus amlodipine and 0.75 (0.37) years versus control. Irbesartan was associated with cost savings of 13,673 Euro and 7,632 Euro patient versus amlodipine and control respectively. The results were robust under a wide range of plausible assumptions.

CONCLUSIONS

Treating patients with hypertension, type 2 diabetes and overt nephropathy using irbesartan was both cost- and life-saving compared to amlodipine and control in the Spanish setting.

An economic evaluation of irbesartan in the treatment of patients with type 2 diabetes, hypertension and nephropathy: cost-effectiveness of Irbesartan in Diabetic Nephropathy Trial (IDNT) in the Belgian and French settings

BACKGROUND

In the Irbesartan in Diabetic Nephropathy Trial (IDNT), treatment with irbesartan demonstrated 23 and 20% reductions in the combined endpoint of doubling of serum creatinine (DSC), end-stage renal disease (ESRD) or death in patients with hypertension, type 2 diabetes and overt nephropathy compared with amlodipine and control, respectively. A simulation model was developed to project long-term cost consequences of the IDNT in Belgium and France.

METHODS

A Markov model simulated progression from nephropathy to DSC, ESRD and death in patients with hypertension, type 2 diabetes and overt nephropathy. Treatment-specific probabilities were derived from IDNT. Country-specific ESRD-related data were retrieved from published sources. Delay in onset of ESRD, life expectancy and mean lifetime costs were calculated for patients with a baseline age of 59 years. Future costs were discounted at 3% per annum (p.a.), and clinical benefits were discounted at 0 and 3% p.a. Extensive sensitivity analyses were performed.

RESULTS

Onset of ESRD was delayed with irbesartan by 1.41 and 1.35 years vs amlodipine and control, respectively. When a 10-year time horizon was considered, delay in ESRD onset led to anticipated improvements in life expectancy of 0.13 years vs amlodipine and 0.26 years vs control. Irbesartan was associated with cost savings of 14 949 and 9205/patient in Belgium, and 20 128 and 13 337 in France, vs amlodipine and control, respectively. The results were robust under a wide range of plausible assumptions.

CONCLUSIONS

Treating patients with hypertension, type 2 diabetes and overt nephropathy using irbesartan was both cost- and life-saving compared with amlodipine and control.

The cost-effectiveness of irbesartan in the treatment of hypertensive patients with type 2 diabetic nephropathy

BACKGROUND

End-stage renal disease (ESRD)-related health care costs are substantial. Improving clinical outcomes in patients at risk of progression to ESRD could lead to considerable health care savings.

OBJECTIVE

We estimated the cost-effectiveness of irbesartan compared with placebo or amlodipine in the treatment of patients with type 2 diabetes mellitus, hypertension, and overt nephropathy.

METHODS

Three treatments for hypertension patients with type 2 diabetes mellitus and nephropathy were assessed: (1) irbesartan, (2) amlodipine, and (3) placebo. A Markov model was developed based on primary data from the Irbesartan in Diabetic Nephropathy Trial and the United States Renal Data System. Projected survival and costs were compared for each treatment at 3-, 10-, and 25-year time horizons. Different assumptions of treatment benefits and costs were tested with use of sensitivity analyses.

RESULTS

At 10 and 25 years, the model projected irbesartan to be both the least costly and most effective (ie, demonstrating a survival advantage) strategy. At 25

The determinants of left ventricular hypertrophy defined by Sokolow-Lyon criteria in untreated hypertensive patients

Left ventricular hypertrophy (LVH) measured by electrocardiography (ECG LVH) in hypertensive patients has been shown to be associated with an increased risk of cardiovascular sequelae. Analysis of the determinants predisposing to ECG LVH may be helpful in the prevention of LVH. The Department of Health and Social Security Hypertension Care Computer Project studied 2994 hypertensive patients in whom an electrocardiogram was recorded while not on treatment. LVH was determined as the voltage sum SV1+RV5 or RV6>or=35 mm using Sokolow-Lyon voltage criteria. The relations were determined between the presence of LVH or voltage sum and different variables. Untreated systolic (SBP) and diastolic (DBP) blood pressure and pulse pressure were positively related to the increasing ECG voltage, while body mass index (BMI) and serum cholesterol were inversely related. Blood glucose and age did not correlate significantly. Patients with the presence of ECG LVH were more often men, black people, smokers and users of alcohol. In multiple logistic regression analyses, SBP, DBP, male gender and black race were positively, whereas BMI was negatively related to the presence of LVH. The positive relation of smoking and negative relation of serum cholesterol concentration to the presence of ECG LVH were apparent in men but not in women. This study confirms the adverse association between ECG LVH and SBP and DBP, male gender, black race and decreased BMI. It also addresses the less well-known associations of blood glucose, cholesterol, smoking and alcohol consumption.

Modeling the impact of adjustable gastric banding on survival in patients with morbid obesity

OBJECTIVE

Morbid obesity is associated with premature death. Adjustable gastric banding may lead to substantial weight loss in patients with morbid obesity. Little is known about the impact of weight loss on survival after adjustable gastric banding. We therefore developed a mathematical model to estimate life expectancy in patients with a body mass index (BMI) > or =40 kg/m(2) undergoing bariatric surgery.

RESEARCH METHODS AND PROCEDURES

We developed a nonhomogeneous Markov chain consisting of five states: the absorbing state ("dead") and the four recurrent states BMI > or =40 kg/m(2), BMI 36 to 39 kg/m(2), BMI 32 to 35 kg/m(2), and BMI 25 to 31 kg/m(2). Scenarios of weight loss and age- and sex-dependent risk of death, as well as BMI-dependent excess mortality were extracted from life tables and published literature. All patients entered the model through the state of BMI > or =40 kg/m(2).

RESULTS

In men aged either 18 or 65 years at the time of surgery, who moved from the state BMI > or =40 kg/m(2) to the next lower state of BMI 36 to 39 kg/m(2), life expectancy increased by 3 and 0.7 years, respectively. In women aged either 18 or 65 years at the time of surgery, who moved from the state BMI > or =40 kg/m(2) to the next lower state BMI 36 to 39 kg/m(2), life expectancy increased by 4.5 and 2.6 years, respectively. Weight loss to lower BMI strata resulted in further gains of life expectancy in both men and women.

DISCUSSION

Within the limitations of the modeling study, adjustable gastric banding in patients with morbid obesity may substantially increase life expectancy.

Economic evaluation of pioglitazone hydrochloride in the management of type 2 diabetes mellitus in Canada

INTRODUCTION

Recently published clinical trial results have demonstrated that, in patients with type 2 diabetes mellitus, treatment with pioglitazone hydrochloride as a first-line therapy can lead to significant improvements in glycosylated haemoglobin, total cholesterol, high density lipoprotein cholesterol and triglycerides. Given the results of these trials, we assessed the cost effectiveness of the use of pioglitazone as a first-line therapy in Canada.

METHODS

A Markov model was used to determine the health outcomes and economic impact for patients with type 2 diabetes, from the perspective of a provincial ministry of health. The model incorporated six complications of diabetes: hypoglycaemia, acute myocardial infarction, stroke, lower extremity amputation, nephropathy, and retinopathy. Transition probabilities and costs were taken from published literature. Analysis compared treatment strategies with different first-line therapies: pioglitazone, glibenclamide (glyburide), metformin, and diet and exercise.

RESULTS

Compared with other strategies, a pioglitazone-based strategy was estimated to reduce the cumulative incidence of severe clinical events and long-term complications by between 23 and 36% and to increase discounted life expectancy by between 0.13 and 0.35 life-years. The discounted incremental cost per life-year gained of a first-line pioglitazone-based strategy was 54,000 Canadian dollars ($Can) compared with metformin, $Can42,000 compared with glibenclamide and $Can27,000 compared with diet and exercise.

CONCLUSIONS

When compared with other currently funded chronic therapy, these results demonstrate that a treatment strategy employing pioglitazone as a first-line therapy may be cost effective for certain patient strata.

New aspects in health economic studies of prevention and treatment of osteoporosis

This review updates the current knowledge with regard to important new clinical data in the field of osteoporosis interventions and discusses the implications for future health economics studies in this field.

Economic and clinical impact of alternative disease management strategies for secondary prevention in type 2 diabetes in the Swiss setting

PRINCIPLES

Different intervention strategies for the optimisation of disease management of diabetes exist and have been shown to increase the proportion of patients receiving screening and examinations and to improve risk factors such as HbA1c, lipids, and blood pressure. Thus, in the long-term, a decrease in diabetic complications and the associated costs could be expected. To address this question, the current analysis used a published diabetes simulation model to analyse the long-term clinical and economic implications of implementing various interventions in the Swiss setting.

METHODS

Based on data from the literature, the short-term effects on clinical variables of multifactorial interventions, including screening for nephropathy and retinopathy, educational programmes and control of cardiovascular risk profile were assessed, and a cost-effectiveness analysis in comparison to standard care was performed. Life expectancy (LE) and total lifetime costs (TC) from the perspective of the health insurance payer were calculated using a long-term Markov simulation model.

RESULTS

The multifactorial intervention led to an improvement in undiscounted LE of 0.56 years (LE = 10.73 and 11.29 years for standard care and multifactorial intervention respectively), and a reduction in 3%-discounted TC of CHF 7313 (10.7%) per patient compared to current standard practice. Extrapolation to the whole Swiss type 2 diabetes population (285,000) showed yearly cost savings of CHF 194 million from the multifactorial intervention.

CONCLUSIONS

The implementation of multifactorial interventions, including improved control of cardiovascular risk factors, combined with early diagnosis and treatment of diabetic complications, could be both cost- and life-saving in the Swiss setting.

Economic and clinical impact of alternative disease management strategies for secondary prevention in type 2 diabetes in the Swiss setting

PRINCIPLES

Different intervention strategies for the optimisation of disease management of diabetes exist and have been shown to increase the proportion of patients receiving screening and examinations and to improve risk factors such as HbA1c, lipids, and blood pressure. Thus, in the long-term, a decrease in diabetic complications and the associated costs could be expected. To address this question, the current analysis used a published diabetes simulation model to analyse the long-term clinical and economic implications of implementing various interventions in the Swiss setting.

METHODS

Based on data from the literature, the short-term effects on clinical variables of multifactorial interventions, including screening for nephropathy and retinopathy, educational programmes and control of cardiovascular risk profile were assessed, and a cost-effectiveness analysis in comparison to standard care was performed. Life expectancy (LE) and total lifetime costs (TC) from the perspective of the health insurance payer were calculated using a long-term Markov simulation model.

RESULTS

The multifactorial intervention led to an improvement in undiscounted LE of 0.56 years (LE = 10.73 and 11.29 years for standard care and multifactorial intervention respectively), and a reduction in 3%-discounted TC of CHF 7313 (10.7%) per patient compared to current standard practice. Extrapolation to the whole Swiss type 2 diabetes population (285,000) showed yearly cost savings of CHF 194 million from the multifactorial intervention.

CONCLUSIONS

The implementation of multifactorial interventions, including improved control of cardiovascular risk factors, combined with early diagnosis and treatment of diabetic complications, could be both cost- and life-saving in the Swiss setting.

Highly active antiretroviral therapy: pharmacoeconomic issues in the management of HIV infection

The advent of highly active antiretroviral therapy (HAART), including protease inhibitors and/or non-nucleoside reverse transcriptase inhibitors, for the treatment of HIV infection has led to a dramatic decline of morbidity and mortality. The acquisition costs of HAART are substantial. However, these costs are partially offset by reduced inpatient care for opportunistic infections and other AIDS-related diseases. Furthermore, job productivity in patients infected with HIV is increased under HAART. In developed countries with a low unemployment rate, the discounted value of savings caused by increased productivity in earlier years exceeds the discounted value of later increases in costs resulting from morbidity. Therefore, HAART represents a very efficient treatment strategy that leads to overall cost savings when taking a societal perspective.

The Mt. Hood challenge: cross-testing two diabetes simulation models

Starting from identical patients with type 2 diabetes, we compared the 20-year predictions of two computer simulation models, a 1998 version of the IMIB model and version 2.17 of the Global Diabetes Model (GDM). Primary measures of outcome were 20-year cumulative rates of: survival, first (incident) acute myocardial infarction (AMI), first stroke, proliferative diabetic retinopathy (PDR), macro-albuminuria (gross proteinuria, or GPR), and amputation. Standardized test patients were newly diagnosed males aged 45 or 75, with high and low levels of glycated hemoglobin (HbA(1c)), systolic blood pressure (SBP), and serum lipids. Both models generated realistic results and appropriate responses to changes in risk factors. Compared with the GDM, the IMIB model predicted much higher rates of mortality and AMI, and fewer strokes. These differences can be explained by differences in model architecture (Markov vs. microsimulation), different evidence bases for cardiovascular prediction (Framingham Heart Study cohort vs. Kaiser Permanente patients), and isolated versus interdependent prediction of cardiovascular events. Compared with IMIB, GDM predicted much higher lifetime costs, because of lower mortality and the use of a different costing method. It is feasible to cross-validate and explicate dissimilar diabetes simulation models using standardized patients. The wide differences in the model results that we observed demonstrate the need for cross-validation. We propose to hold a second 'Mt Hood Challenge' in 2001 and invite all diabetes modelers to attend.

Outline of a diabetes disease management model: principles and applications

A complex interactive computer model was developed to determine the health outcomes and economic consequences of different diabetes interventions for user-defined observation periods. The interventions include intensive or conventional insulin therapy, different oral hypoglycaemic medications, different screening and treatment strategies for micro-vascular complications, different treatment strategies for end-stage complications, or multi-factorial interventions. The analyses can be performed on different sub-groups of type 1 and 2 diabetic patients, defined in terms of age, gender, baseline risk factors and pre-existing complications. The model performs real-time simulations. Full on-screen documentation of the model structure, logic, calculations and data sources is available to maximize the model's transparency. Economic and clinical data used in the disease management model are editable by the user, allowing the input of new data as they become available, the creation of country-specific, HMO-specific, or provider-specific versions of the model, and the exploration of new hypotheses ('what-if' analyses). The approach used allows maximum flexibility, adaptability, and transparency within the model structure. For the user-defined patient cohorts and intervention strategies the diabetes disease management model compares life expectancy, expected incidence and prevalence of complications as well as expected life-time (or shorter) treatment cost. Diabetes and complication management strategies can be compared in different patient populations in a variety of realistic clinical settings. The model allows extrapolation of results obtained from relatively short-term clinical trials to longer-term medical outcomes, and from trial populations to real-life populations providing a tangible yardstick to judge the quality of diabetes care. The model was used to evaluate diabetes care options in Germany, France, Switzerland, UK and US.

[Increased clinical and economic advantages using PROSIT (proteinuria screening and intervention) in type 2 diabetic patients]

BACKGROUND AND OBJECTIVE

Even though there are simple and cost-effective means for the early diagnosis of diabetic nephropathy, only a small proportion of diabetics in Germany is regularly tests for microalbuminuria. On the basis of evidence-based knowledge and of international guidelines the PROSIT project (proteinuria screening and intervention) aims to make good this deficiency in the German Federal Republic by introducing nephropathy screening and a structured intervention to improve blood sugar and blood pressure regulation, optimizing lipid metabolism and nutritional intake. It was the aim of this study to assess with a computer-aided diabetes model the clinical value and cost-effectiveness of such an intervention.

PATIENTS AND METHODS

From data collected for 589 diabetics who participated in the PROSIT project, the short-time effects after one year on HbA1c, systolic blood pressure and lipid levels were obtained and cost-effectiveness compared with that of standard care. Life expectancy, life-time costs to be met by health insurance and event frequency of the diabetic nephropathy stages were calculated with a Markov model for type 2 diabetics.

RESULTS

PROSIT improved individual life expectancy by 0.23 years with reduction of life-time costs by DM 9,772 (ca. $4,900). The cumulative incidence of microalbuminuria was lowered by 30.5%, that of terminal renal failure by 55.9%. Even after discounting the results (i.e. the inclusion of time preference for cost and benefit) and stepwise changes of all variables by +/- 10%, PROSIT remained the more cost-effective variant.

CONCLUSION

From a health economy viewpoint PROSIT is superior to standard management. Early recognition of albuminuria and the introduction of a multifactorial treatment strategy make it possible to delay progression to terminal renal failure. In addition to its clinical benefits, prevention of dialysis and transplantation would reduce the annual savings of the health care system by several billion DM.