Cost-effectiveness of rosiglitazone oral combination for the treatment of type 2 diabetes in Germany

Health economic evaluations based on routine data in Germany: a systematic review

Background

Improved data access and funding for health services research have promoted the application of routine data to measure costs and effects of interventions within the German health care system. Following the trend towards real world evidence, this review aims to evaluate the status and quality of health economic evaluations based on routine data in Germany.

Methods

To identify relevant economic evaluations, a systematic literature search in the databases PubMed and EMBASE was complemented by a manual search. The included studies had to be full economic evaluations using German routine data to measure either costs, effects, or both. Study characteristics were assessed with a structured template. Additionally, the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) were used to measure quality of reporting.

Results

In total, 912 records were identified and 35 studies were included in the further analysis. The majority of these studies was published in the past 5 years (n = 27, 77.1%) and used insurance claims data as a source of routine data (n = 30, 85.7%). The most common method used for handling selection bias was propensity score matching. With regard to the reporting quality, 42.9% (n = 15) of the studies satisfied at least 80% of the criteria on the CHEERS checklist.

Conclusions

This review confirms that routine data has become an increasingly common data source for health economic evaluations in Germany. While most studies addressed the application of routine data, this analysis reveals deficits in considering methodological particularities and in reporting quality of economic evaluations based on routine data. Nevertheless, this review demonstrates the overall potential of routine data for economic evaluations.

Electronic supplementary material

The online version of this article (10.1186/s12913-018-3080-3) contains supplementary material, which is available to authorized users.

Progression to insulin for patients with diabetes mellitus on dual oral antidiabetic therapy using the US Department of Defense Database

AIM

To compare 'progression to insulin' for three cohorts on oral antidiabetic medication combinations: metformin/sulphonylurea (Met/SU), metformin/thiazolidinedione (Met/TZD) and sulphonylurea/thiazolidinedione (SU/TZD).

METHODS

Retrospective cohort analysis design was used. The subjects were US nationwide members of military and their families. A total of 5608 patients who were on antidiabetic monotherapy for at least 1 year before adding a second agent to their medication regimen between October 2001 and September 2008 participated in this study. Mean age ranged from 64 to 71 years among the cohorts. Cox regression compared the progression to insulin, adjusting for demographics, months of follow-up and co-morbidities [measured with Chronic Disease Score (CDS)].

RESULTS

By the end of the 2- to 6-year follow-up period, 14.3% of the Met/TZD cohort, 23.6% of the Met/SU cohort and 28.2% of the SU/TZD cohort had insulin added to their regimen. Those in the Met/SU cohort had a 1.8 times higher probability of progression to insulin than those in the Met/TZD cohort [odds ratio (OR) = 1.80, 95% confidence interval (CI) = 1.51-2.14), and those in the SU/TZD cohort had a 2.5 times higher probability of progression to insulin than those in the Met/TZD cohort (OR = 2.51, 95% CI = 2.04-3.08).

CONCLUSION

When sensitizers were paired (Met/TZD), a lower percentage of patients progressed to insulin during the study period, as opposed to patients who used a combination of a secretagogue with a sensitizer (SU/TZD or Met/SU).

Cost effectiveness of saxagliptin and metformin versus sulfonylurea and metformin in the treatment of type 2 diabetes mellitus in Germany: a Cardiff diabetes model analysis

BACKGROUND

The lack of adequate glycaemic control for patients with type 2 diabetes mellitus (T2DM), especially with existing second-line therapies, represents an unmet medical need. Of the newer therapies, the incretin-based medicines, such as saxagliptin, look promising to consolidate second-line pharmacotherapy.

OBJECTIVE

This study evaluates the long-term economic consequences of saxagliptin versus sulfonylurea (glipizide) as second-line therapy when used in combination with metformin after failure of monotherapy treatment with metformin, in patients with T2DM in Germany.

METHODS

A published discrete event simulation model with a fixed-time increment was used to model the effects of different treatment scenarios over a 40-year (life-) time horizon. Disease progression was modelled using evidence from the United Kingdom Prospective Diabetes Study (UKPDS) 68. The treatment sequence matched that of published German guidelines, and efficacy and safety data were derived from published sources. The model assumes that quality-adjusted life-years (QALYs) are affected by complications, hypoglycaemic events and weight change over a lifetime. Costs were specific to the German setting, where sulfonylureas are generic. Costs and effects were discounted annually at 3%. The extended perspective of the national sick funds was adopted, and recommendations from the Institute for Quality and Efficiency in Health Care (IQWiG) were considered.

RESULTS

In the base-case analysis, treatment with saxagliptin plus metformin was associated with a lower incidence of both symptomatic and severe hypoglycaemic events, resulting in an incremental benefit of 0.12 QALYs and an incremental cost-effectiveness ratio (ICER) of €13,931 per QALY gained compared with sulfonylurea plus metformin (year of costing 2009). Modest reductions in all macro- and microvascular complications were seen in those receiving saxagliptin plus metformin compared with sulfonylurea plus metformin. Sensitivity analysis showed that treatment-related weight changes, as a risk factor for complications, represent the most influential driver of cost effectiveness.

CONCLUSION

The study demonstrated improved outcomes with saxagliptin at a cost that would likely be considered acceptable in the German setting. Furthermore, the findings of the sensitivity analysis suggest that the results are robust to various assumptions concerning input variables and modelling assumptions.

Economic models in type 2 diabetes

OBJECTIVE

To identify and critically appraise cost-effectiveness models developed to evaluate type 2 diabetes (T2D) treatments and to assess which types of treatment effects they capture.

RESEARCH DESIGN AND METHODS

A systematic search was performed in MEDLINE, EMBASE, Centre for Reviews and Dissemination databases at the University of York, and Health Economic Evaluation Database for the period to September 2008. The websites of Health Technology Assessment (HTA) bodies in different countries were also screened for relevant models. For each of the identified original models, details of the structure, data in- and outputs were extracted and the overall quality of the model in terms of the combination of structure, assumptions and data inputs were appraised using published criteria.

RESULTS

Seventy-eight articles and 41 HTAs reporting relevant economic evaluations were identified. There were ten models with multiple publications, and a further ten models with one associated publication. The critical review demonstrated that most had the same fundamental structure, used similar micro-simulation techniques and were based on the same key data sources. However, the process for identification of relevant data and their synthesis, and the selection of outcomes lacked transparency. The models differed according to the extent and type of interventions they evaluated and which diabetes complications and treatment-related adverse events were captured. For example, just one model incorporated changes in patient weight, despite the fact that weight gain can be a side-effect of some treatments, and weight loss a potential benefit of others.

CONCLUSIONS

Whilst many economic models exist in T2D, most share common features such as the model type. Identified shortcomings are lack of transparency in data identification and evidence synthesis as well as the selection of the modelled outcomes. Future models should aim to include all relevant treatment outcomes, whether these relate to effects on underlying diabetes and its complications or to short- or long-term side effects of treatment.

UKPDS-modelling of cardiovascular risk assessment and lifetime simulation of outcomes

Although known principally as a clinical trial, the UK Prospective Diabetes Study (UKPDS) provided longitudinal data which helped define the natural history of cardiovascular complications in Type 2 diabetes. Using clinical, epidemiological, statistical and economics methods, UKPDS investigators developed mathematical models that helped define predictors (risk factors) for cardiovascular disease including angina, myocardial infarction, stroke, peripheral vascular disease and death in Type 2 diabetes. The UKPDS made clearer the contributions to risk of age, hyperglycaemia, elevated blood pressure, adverse blood lipids and smoking. Equations were developed, combined and incorporated into the UKPDS Risk Engine and the UKPDS Outcomes models. For example, the UKPDS risk engine-version 2-estimates that a white 62-year-old man with 11 years of Type 2 diabetes, a glycated haemoglobin of 8.3%, a systolic blood pressure of 145 mmHg and total and high-density lipoprotein cholesterol values of 5.8 and 1.1 mmol/l who did not smoke has a 33% chance of having overt coronary heart disease within 10 years. These models contribute to the estimation of risk and/or health outcomes adjusted for quality of life for use by, amongst others, clinicians, trialists, health planners, guideline developers and health economists.

Lifetime health consequences and cost-effectiveness of rosiglitazone in combination with metformin for the treatment of type 2 diabetes in Spain

OBJECTIVE

To assess the lifetime diabetes health consequences and cost-effectiveness in Spain of rosiglitazone in combination with metformin for the treatment of type 2 diabetes in overweight and obese patients failing to maintain glycaemic control with metformin monotherapy compared with conventional care of metformin in combination with either sulfonylureas or bedtime insulin.

RESEARCH DESIGN AND METHODS

The Diabetes Decision Analysis of Cost--Type 2 was adapted for clinical practice and healthcare funding in Spain, and was calibrated with Spanish epidemiological, healthcare resource use and cost data, taking the perspective of the Spanish National Health System. The model simulates lifetime treatment histories, complications and consequences of type 2 diabetes, and associated health outcomes and costs for age and sex-matched cohorts of 1000 overweight and obese patients. The primary health outcome measures compared are glycaemic control, time to insulin, incidence and prevalence of coronary heart disease, stroke, clinical nephropathy, ulceration and amputation, and severe visual loss, and incremental life-years and quality-adjusted life-years (QALYs).

RESULTS

Rosiglitazone in combination with metformin produces better glycaemic control than conventional care of metformin in combination with either sulfonylureas or bedtime insulin in most patients, and extends the viability of combination therapy by between 6 and 13 years before requiring insulin. Rosiglitazone patients have a longer life expectancy, gaining between 106 and 175 additional life-years per 1000 patients, experience fewer episodes of coronary disease and clinical nephropathy, and live for longer periods free of complications. The improvements in morbidity and mortality are projected to yield between 134 and 238 additional QALY per 1000 patients over their lifetime. Discounted incremental cost-effectiveness ratios range from euro 9406 to euro 23,514 per QALY gained.

CONCLUSION

The model predicts that rosiglitazone in combination with metformin is a cost-effective intervention for the treatment of both overweight and obese patients with type 2 diabetes when compared with conventional care in Spain.