How Do Diabetes Models Measure Up? A Review of Diabetes Economic Models and ADA Guidelines

Prediction of complications in health economic models of type 2 diabetes: a review of methods used

AIM

Diabetes health economic (HE) models play important roles in decision making. For most HE models of diabetes 2 diabetes (T2D), the core model concerns the prediction of complications. However, reviews of HE models pay little attention to the incorporation of prediction models. The objective of the current review is to investigate how prediction models have been incorporated into HE models of T2D and to identify challenges and possible solutions.

METHODS

PubMed, Web of Science, Embase, and Cochrane were searched from January 1, 1997, to November 15, 2022, to identify published HE models for T2D. All models that participated in The Mount Hood Diabetes Simulation Modeling Database or previous challenges were manually searched. Data extraction was performed by two independent authors. Characteristics of HE models, their underlying prediction models, and methods of incorporating prediction models were investigated.

RESULTS

The scoping review identified 34 HE models, including a continuous-time object-oriented model (n = 1), discrete-time state transition models (n = 18), and discrete-time discrete event simulation models (n = 15). Published prediction models were often applied to simulate complication risks, such as the UKPDS (n = 20), Framingham (n = 7), BRAVO (n = 2), NDR (n = 2), and RECODe (n = 2). Four methods were identified to combine interdependent prediction models for different complications, including random order evaluation (n = 12), simultaneous evaluation (n = 4), the 'sunflower method' (n = 3), and pre-defined order (n = 1). The remaining studies did not consider interdependency or reported unclearly.

CONCLUSIONS

The methodology of integrating prediction models in HE models requires further attention, especially regarding how prediction models are selected, adjusted, and ordered.

Cost-Effectiveness of Once-Weekly Semaglutide 1 mg versus Canagliflozin 300 mg in Patients with Type 2 Diabetes Mellitus in a Canadian Setting

OBJECTIVE

Our objective was to evaluate the long-term cost-effectiveness of once-weekly semaglutide 1 mg versus once-daily canagliflozin 300 mg in patients with type 2 diabetes mellitus (T2DM) uncontrolled with metformin from the healthcare payer and societal perspectives in Canada.

METHODS

Head-to-head data from the SUSTAIN 8 randomised trial (NCT03136484) were extrapolated over 40 years using economic simulation modelling. The cost-effectiveness of once-weekly semaglutide 1 mg versus canagliflozin 300 mg for treating T2DM was estimated using the Swedish Institute for Health Economics-Diabetes Cohort Model (IHE-DCM) and the Economic and Health Outcomes Model of T2DM (ECHO-T2DM). Unit costs and disutility weights capturing treatments and key macro- and microvascular complications were sourced from the literature to best match the Canadian setting. A probabilistic base-case simulation and sensitivity analyses were conducted.

RESULTS

Once-weekly semaglutide 1 mg was associated with reductions in macro- and microvascular complications, yielding incremental cost-effectiveness ratios (ICERs) of (Canadian dollars [CAD]) CAD16,392 and 18,098 per incremental quality-adjusted life-year (QALY) gained versus canagliflozin 300 mg for IHE-DCM and ECHO-T2DM, respectively, from a healthcare payer perspective. Accounting for productivity loss as well, ICERs were CAD14,127 and 13,188 per QALY gained for IHE-DCM and ECHO-T2DM, respectively, from a societal perspective. Sensitivity analyses confirmed that the base-case results were robust to changes in input parameters and assumptions used.

CONCLUSIONS

At a willingness-to-pay threshold of CAD50,000 per QALY gained, once-weekly semaglutide 1 mg was cost-effective over 40 years versus once-daily canagliflozin 300 mg for the treatment of T2DM in patients failing to maintain glycemic control with metformin alone.

A review of simulation models for the long-term management of type 2 diabetes in low-and-middle income countries

INTRODUCTION

The burden of type 2 diabetes is steadily increasing in low-and-middle-income countries, thereby posing a major threat from both a treatment, and funding standpoint. Although simulation modelling is generally relied upon for evaluating long-term costs and consequences associated with diabetes interventions, no recent article has reviewed the characteristics and capabilities of available models used in low-and-middle-income countries. We review the use of computer simulation modelling for the management of type 2 diabetes in low-and-middle-income countries.

METHODS

A search for studies reporting computer simulation models of the natural history of individuals with type 2 diabetes and/or decision models to evaluate the impact of treatment strategies on these populations was conducted in PubMed. Data were extracted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and assessed using modelling checklists. Publications before the year 2000, from high-income countries, studies involving animals and analyses that did not use mathematical simulations were excluded. The full text of eligible articles was sourced and information about the intervention and population being modelled, type of modelling approach and the model structure was extracted.

RESULTS

Of the 79 articles suitable for full text review, 44 studies met the inclusion criteria. All were cost-effectiveness/utility studies with the majority being from the East Asia and Pacific region (n = 29). Of the included studies, 34 (77.3%) evaluated the cost-effectiveness of pharmacological interventions and approximately 75% of all included studies used HbA1c as one of the treatment effects of the intervention. 32 (73%) of the publications were microsimulation models, and 29 (66%) were state-transition models. Most of the studies utilised annual cycles (n = 29, 71%), and accounted for costs and outcomes over 20 years or more (n = 38, 86.4%).

CONCLUSIONS

While the use of simulation modelling in the management of type 2 diabetes has been steadily increasing in low-and-middle-income countries, there is an urgent need to invest in evaluating therapeutic and policy interventions related to type 2 diabetes in low-and-middle-income countries through simulation modelling, especially with local research data. Moreover, it is important to improve transparency and credibility in the reporting of input data underlying model-based economic analyses, and studies.

Developing a health economic model for Asians with type 2 diabetes based on the Japan Diabetes Complications Study and the Japanese Elderly Diabetes Intervention Trial

INTRODUCTION

Cost-effectiveness analyses are becoming increasingly important in Japan following the introduction of a health technology assessment scheme. The study objective was to develop an economic model to evaluate the cost-effectiveness of two interventions for type 2 diabetes in a Japanese population.

RESEARCH DESIGN AND METHODS

The Japan Diabetes Complications Study/Japanese Elderly Diabetes Intervention Trial risk engine (JJRE) Cost-Effectiveness Model (JJCEM) was developed, incorporating validated risk equations in Japanese patients with type 2 diabetes from the JJRE. Weibull regression models were developed for progression of the model outcomes, and a targeted literature review was performed to inform default values for utilities and costs. To illustrate outcomes, two simulated analyses were performed in younger (aged 40 years) and older (aged 80 years) Japanese populations, comparing a hypothetical treatment with placebo.

RESULTS

The model considers a population based on user-defined values for 11 baseline characteristic parameters and simulates rates of diabetic complications over a defined time horizon. Costs, quality-adjusted life years, and an incremental cost-effectiveness ratio are estimated. The model provides disaggregated results for two competing interventions, allowing visualization of the key drivers of cost and utility. A scatterplot of simulations and cost-effectiveness acceptability curve are generated for each analysis.

CONCLUSIONS

This is the first cost-effectiveness model for East Asian patients with type 2 diabetes, developed using Japan-specific risk equations. This population constitutes the largest share of the global population with diabetes, making this model highly relevant. The model can be used to evaluate the cost-effectiveness of anti-diabetic interventions in patients with type 2 diabetes in Japan and other East Asian populations.

Macrovascular Risk Equations Based on the CANVAS Program

BACKGROUND

Widely used risk equations for cardiovascular outcomes for individuals with type 2 diabetes mellitus (T2DM) have been incapable of predicting cardioprotective effects observed in recent cardiovascular outcomes trials (CVOTs) involving individuals with T2DM at high risk for or with established cardiovascular disease (CVD).

OBJECTIVE

We developed cardiovascular and mortality risk equations using patient-level data from the CANVAS (CANagliflozin cardioVascular Assessment Study) Program to address this shortcoming.

METHODS

Data from 10,142 patients with T2DM at high risk for or with established CVD, randomized to canagliflozin + standard of care (SoC) or SoC alone and followed for a mean duration of 3.6 years in the CANVAS Program were used to derive parametric risk equations for myocardial infarction (MI), stroke, hospitalization for heart failure (HHF), and death. Accumulated knowledge from the widely used UKPDS-OM2 (United Kingdom Prospective Diabetes Study Outcomes Model 2) was leveraged, and any departures in parameterization were limited to those necessary to provide adequate goodness of fit. Candidate explanatory covariates were selected using only the placebo arm to minimize confounding effects. Internal validation was performed separately by study treatment arm.

RESULTS

UKPDS-OM2 predicted CANVAS Program outcomes poorly. Recalibrating UKPDS-OM2 intercepts improved calibration in some cases. Refitting the coefficients but otherwise preserving the UKPDS-OM2 structure improved the fit substantially, which was sufficient for stroke and death. For MI, reselecting UKPDS-OM2 covariates and functional form proved sufficient. For HHF, selection from a broad set of candidate covariates and inclusion of a canagliflozin indicator was required.

CONCLUSION

These risk equations address some of the limitations of widely used risk equations, such as the UKPDS-OM2, for modeling cardioprotective treatments for individuals with T2DM and high cardiovascular risk, including derivation from overly healthy patients treated with agents that lack cardioprotection and have been described as reflecting a different therapeutic era. Future work is needed to examine external validity.

Healthcare utilization and direct medical cost in the years during and after cancer diagnosis in patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

There is uncertainty about the direct medical costs of type 2 diabetes patients with cancers.

MATERIALS AND METHODS

A population-based retrospective cohort of 99,915 type 2 diabetes patients from the Hong Kong Hospital Authority between 2006 and 2017 was assembled. A total of 16,869 patients who had an initial cancer diagnosis after type 2 diabetes diagnosis were matched with 83,046 patients without cancer (controls) using a matching ratio of up to one-to-five propensity score-matching method. Patients were divided into four categories according to life expectancy. Healthcare service utilization and direct medical costs during the index year, subsequent years and mortality year were compared between patients with and without cancer in each category.

RESULTS

Medical costs of cancer patients in the index year ranged from $US27,533 for patients who died in <1 year to $US11,303 for those survived >3 years. Cancer patients had significantly greater expenditures than controls in the index year (all P < 0.001) and subsequent years ($US4,569 vs $US4,155, P < 0.001). Cancer patients also had greater costs in the year of death, and the difference was significant for patients who survived >3 years after the index year ($US32,558 vs $US28,260). For patients in both groups, patients who survived >3 years had significantly lower costs than those who died in <1 year. Costs incurred in the mortality year were greater than those in the index year and subsequent years. Hospitalization accounted for >90% of the medical costs for both groups in the mortality year.

CONCLUSIONS

Type 2 diabetes patients with cancers incurred greater medical costs in the diagnosis, ensuing and mortality years than type 2 diabetes patients without cancers.

Comparing the Cohort and Micro-Simulation Modeling Approaches in Cost-Effectiveness Modeling of Type 2 Diabetes Mellitus: A Case Study of the IHE Diabetes Cohort Model and the Economics and Health Outcomes Model of T2DM

BACKGROUND

Economic modeling is widely used in estimating cost-effectiveness in type 2 diabetes mellitus. Because type 2 diabetes is complex and patients are heterogenous, the cohort modeling approach may generate biased estimates of costeffectiveness. The IHE Diabetes Cohort Model (IHE-DCM) was constructed using the cohort approach as an alternative for stakeholders with limited resources, some of whom have voiced reasonable concerns about a lack of transparency with type 2 diabetes micro-simulation models and long run times.

OBJECTIVES

The objective of this study was to inform decision makers by investigating the direction and magnitude of bias of IHE-DCM cost-effectiveness estimates that can be attributed to the cohort modeling approach.

METHODS

Simulation scenarios inspired by the 9th Mount Hood Diabetes Challenge were simulated with IHE-DCM and with a micro-simulation model, the Economic and Health Outcomes Model of T2DM (ECHO-T2DM), and key metrics (absolute and incremental costs and quality-adjusted life-years, event rates, and cost-effectiveness) were compared for evidence of systematic differences. The models were harmonized to the extent possible to ensure that differences were driven primarily by the unit of observation and not by other model differences.

RESULTS

IHE-DCM run times were faster and IHE-DCM produced uniformly larger estimates of absolute life-years, quality-adjusted life-years, and costs than ECHO-T2DM but smaller between-arm (incremental) differences. Estimated incremental cost-effectiveness ratios and net monetary benefits varied similarly and predictably across the scenarios. On average, IHE-DCM estimates of incremental cost-effectiveness ratios and net monetary benefits were CAN$269 (3%) and CAN$2935 (10%) smaller, respectively, than ECHO-T2DM.

CONCLUSIONS

There was little evidence that estimated cost-effectiveness metrics, the outcomes that matter most to stakeholders, differed systematically.

Cost-Effectiveness Analysis of Linagliptin in Japan Based on Results from the Asian Subpopulation in the CARMELINA® Trial

INTRODUCTION

We evaluated the cost-effectiveness of linagliptin in Japan by estimating the lifetime outcome based on clinical event rates from the Asian subpopulation of the CARMELINA trial. In CARMELINA, linagliptin added to standard of care (SoC) versus SoC demonstrated noninferiority with regard to risk of composite cardiovascular (CV) outcome in patients with type 2 diabetes at high risk of CV and kidney events. Issues resulting from conducting a cost-effectiveness analysis using data from a clinical noninferiority study were also investigated.

METHODS

A microsimulation model was used to evaluate linagliptin/SoC versus SoC in terms of direct costs and quality-adjusted life years (QALYs) from a Japanese public healthcare payer's perspective. Cost data were obtained from recent Japanese publications. The time horizon was defined as lifetime, and the discount rate for costs and effectiveness was 2% per year. One-way and probabilistic sensitivity analyses were performed.

RESULTS

In the base case analysis, and taking medical history into account, the incremental effectiveness of linagliptin/SoC versus SoC was 1.34 QALYs, and the incremental cost for linagliptin was - 545,319 yen. In the one-way sensitivity analysis, the parameter which most affected the results was the hazard ratio for renal failure of linagliptin/SoC compared with SoC. The probabilistic sensitivity analysis showed that the probability of reduced costs and increased effectiveness (dominant) was 48%. Assuming an incremental cost-effectiveness ratio (ICER) threshold of 5 million yen, the probability that the ICER was below the threshold was 89% for linagliptin/SoC compared with SoC.

CONCLUSIONS

This evaluation, using Asian subpopulation data from the CARMELINA trial, suggested that the cost-effectiveness of linagliptin for a lifetime outcome was favourable in Japan. However, the results must be interpreted cautiously because of the noninferiority trial data source, which might cause ICER variations for each parameter.

Health Care Costs Associated With Macrovascular, Microvascular, and Metabolic Complications of Type 2 Diabetes Across Time: Estimates From a Population-Based Cohort of More Than 0.8 Million Individuals With Up to 15 Years of Follow-up

OBJECTIVE

Developing country-specific unit-cost catalogs is a key area for advancing economic research to improve medical and policy decisions. However, little is known about how health care costs vary by type 2 diabetes (T2D) complications across time in Asian countries. We sought to quantify the economic burden of various T2D complications in Taiwan.

RESEARCH DESIGN AND METHODS

A nationwide, population-based, longitudinal study was conducted to analyze 802,429 adults with newly diagnosed T2D identified during 1999-2010 and followed up until death or 31 December 2013. Annual health care costs associated with T2D complications were estimated, with multivariable generalized estimating equation models adjusted for individual characteristics.

RESULTS

The mean annual health care cost was $281 and $298 (2017 U.S. dollars) for a male and female, respectively, diagnosed with T2D at age <50 years, with diabetes duration of <5 years, and without comorbidities, antidiabetic treatments, and complications. Depression was the costliest comorbidity, increasing costs by 64-82%. Antidiabetic treatments increased costs by 72-126%. For nonfatal complications, costs increased from 36% (retinopathy) to 202% (stroke) in the event year and from 13% (retinopathy or neuropathy) to 49% (heart failure) in subsequent years. Costs for the five leading costly nonfatal subtype complications increased by 201-599% (end-stage renal disease with dialysis), 37-376% (hemorrhagic/ischemic stroke), and 13-279% (upper-/lower-extremity amputation). For fatal complications, costs increased by 1,784-2,001% and 1,285-1,584% for cardiovascular and other-cause deaths, respectively.

CONCLUSIONS

The cost estimates from this study are crucial for parameterizing diabetes economic simulation models to quantify the economic impact of clinical outcomes and determine cost-effective interventions.

Economic Simulation Modeling in Type 2 Diabetes

PURPOSE OF REVIEW

This paper provides an overview of type 2 diabetes economic simulation modeling and reviews current topics of discussion and major challenges in the field.

RECENT FINDINGS

Important challenges in the field include increasing the generalizability of models and improving transparency in model reporting. To identify and address these issues, modeling groups have organized through the Mount Hood Diabetes Challenge meetings and developed tools (i.e., checklist, impact inventory) to standardize modeling methods and reporting of results. Accordingly, many newer diabetes models have begun utilizing these tools, allowing for improved comparability between diabetes models. In the last two decades, type 2 diabetes simulation models have improved considerably, due to the collaborative work performed through the Mount Hood Diabetes Challenge meetings. To continue to improve diabetes models, future work must focus on clarifying diabetes progression in racial/ethnic minorities and incorporating equity considerations into health economic analysis.

Performance of the UKPDS Outcomes Model 2 for Predicting Death and Cardiovascular Events in Patients with Type 2 Diabetes Mellitus from a German Population-Based Cohort

BACKGROUND AND OBJECTIVE

Accurate prediction of relevant outcomes is important for targeting therapies and to support health economic evaluations of healthcare interventions in patients with diabetes. The United Kingdom Prospective Diabetes Study (UKPDS) risk equations are some of the most frequently used risk equations. This study aims to analyze the calibration and discrimination of the updated UKPDS risk equations as implemented in the UKPDS Outcomes Model 2 (UKPDS-OM2) for predicting cardiovascular (CV) events and death in patients with type 2 diabetes mellitus (T2DM) from population-based German samples.

METHODS

Analyses are based on data of 456 individuals diagnosed with T2DM who participated in two population-based studies in southern Germany (KORA (Cooperative Health Research in the Region of Augsburg)-A: 1997/1998, n = 178; KORA-S4: 1999-2001, n = 278). We compared the participants' 10-year observed incidence of mortality, CV mortality, myocardial infarction (MI), and stroke with the predicted event rate of the UKPDS-OM2. The model's calibration was evaluated by Greenwood-Nam-D'Agostino tests and discrimination was evaluated by C-statistics.

RESULTS

Of the 456 participants with T2DM (mean age 65 years, mean diabetes duration 8 years, 56% male), over the 10-year follow-up time 129 died (61 due to CV events), 64 experienced an MI, and 46 a stroke. The UKPDS-OM2 significantly over-predicted mortality and CV mortality by 25% and 28%, respectively (Greenwood-Nam-D'Agostino tests: p < 0.01), but there was no significant difference between predicted and observed MI and stroke risk. The model poorly discriminated for death (C-statistic [95% confidence interval] = 0.64 [0.60-0.69]), CV death (0.64 [0.58-0.71]), and MI (0.58 [0.52-0.66]), and failed to discriminate for stroke (0.57 [0.47-0.66]).

CONCLUSIONS

The study results demonstrate acceptable calibration and poor discrimination of the UKPDS-OM2 for predicting death and CV events in this population-based German sample. Those limitations should be considered when using the UKPDS-OM2 for economic evaluations of healthcare strategies or using the risk equations for clinical decision-making.

Cost Effectiveness of Once-Weekly Semaglutide Versus Once-Weekly Dulaglutide in the Treatment of Type 2 Diabetes in Canada

OBJECTIVE

The aim of this study was to assess the cost effectiveness of semaglutide versus dulaglutide, as an add-on to metformin monotherapy, for the treatment of type 2 diabetes (T2D), from a Canadian societal perspective.

METHODS

The Swedish Institute for Health Economics Cohort Model of T2D was used to assess the cost effectiveness of once-weekly semaglutide (0.5 or 1.0 mg) versus once-weekly dulaglutide (0.75 or 1.5 mg) over a 40-year time horizon. Using data from the SUSTAIN 7 trial, which demonstrated comparatively greater reductions in glycated hemoglobin (HbA1c), body mass index and systolic blood pressure with semaglutide, compared with dulaglutide, a deterministic base-case and scenario simulation were conducted. The robustness of the results was evaluated with probabilistic sensitivity analyses and 15 deterministic sensitivity analyses.

RESULTS

The base-case analysis indicated that semaglutide is a dominant treatment option, compared with dulaglutide. Semaglutide was associated with lower total costs (Canadian dollars [CAN$]) versus dulaglutide for both low-dose (CAN$113,287 vs. CAN$113,690; cost-saving: CAN$403) and high-dose (CAN$112,983 vs. CAN$113,695; cost-saving: CAN$711) comparisons. Semaglutide resulted in increased quality-adjusted life-years (QALYs) and QALY gains, compared with dulaglutide, for both low-dose (11.10 vs. 11.07 QALYs; + 0.04 QALYs) and high-dose (11.12 vs. 11.07 QALYs; + 0.05 QALYs) comparisons. The probabilistic sensitivity analysis showed that for 66-73% of iterations, semaglutide was either dominant or was considered cost effective at a willingness-to-pay threshold of CAN$50,000.

CONCLUSIONS

From a Canadian societal perspective, semaglutide may be a cost-effective treatment option versus dulaglutide in patients with T2D who are inadequately controlled on metformin monotherapy.

Cost-effectiveness of Simple Insulin Infusion Devices Compared to Multiple Daily Injections in Uncontrolled Type 2 Diabetics in the United States Based on a Simulation Model

BACKGROUND

As type 2 diabetes (T2D) progresses, administering basal and bolus insulin through multiple daily injections (MDI) is often required to achieve target control, although many people fail to achieve target levels. Continuous subcutaneous insulin infusion (CSII) treatment with traditional pumps has proven effective in this population, but use remains limited in T2D due to CSII cost and complexity. A new class of simple insulin infusion devices have been developed which are simpler to use and less expensive. This paper assesses at what price one such simple insulin infusion device, PAQ® (Cequr SA, Switzerland), may be cost-effective compared to MDI in people with T2D not in glycemic control in the United States.

METHODS

Published equations were used in a simulation model to project long-term cost-effectiveness over 40 years, combined with data from the recent OpT2mise study, assuming similar efficacy of CSII and simple insulin infusion. Cost-effectiveness was pre-defined in relation to per capita gross domestic product (GDP), where incremental cost-effectiveness ratios below 1X the per capita GDP per quality-adjusted life year (QALY) gained were defined as "highly cost-effective" and below 3X GDP per capita as "cost-effective."

RESULTS

Simple insulin infusion resulted in 0.17 QALYs gained per patient compared to MDI, along with lifetime cost-savings of USD 66 883 per person due to reduced insulin use and less complications. Analyses on price sensitivity of simple insulin infusion indicated that a device such as the PAQ is cost-effective compared with MDI up to price points of around USD 17 per day.

CONCLUSIONS

For people with T2D not in glycemic control on MDI, simple insulin infusion devices such as PAQ have the potential to be highly cost-effective in the United States.