Towards Renewed Health Economic Simulation of Type 2 Diabetes: Risk Equations for First and Second Cardiovascular Events from Swedish Register Data

Abstract

ObjectivePredicting the risk of future events is an essential part of health economic simulation models. In pursuit of this goal, the current study aims to predict the risk of developing first and second acute myocardial infarction, heart failure, non-acute ischaemic heart disease, and stroke after diagnosis in patients with type 2 diabetes, using data from the Swedish National Diabetes Register.Material and MethodsRegister data on 29,034 patients with type 2 diabetes were analysed over five years of follow up (baseline 2003). To develop and validate the risk equations, the sample was randomly divided into training (75%) and test (25%) subsamples. The Weibull proportional hazard model was used to estimate the coefficients of the risk equations, and these were validated in both the training and the test samples.ResultsIn total, 4,547 first and 2,418 second events were observed during the five years of follow up. Experiencing a first event substantially elevated the risk of subsequent events. There were heterogeneities in the effects of covariates within as well as between events; for example, while for females the hazard ratio of having a first acute myocardial infarction was 0.79 (0.70–0.90), the hazard ratio of a second was 1.21 (0.98–1.48). The hazards of second events decreased as the time since first events elapsed. The equations showed adequate calibration and discrimination (C statistics range: 0.70–0.84 in test samples).ConclusionThe accuracy of health economic simulation models of type 2 diabetes can be improved by ensuring that they account for the heterogeneous effects of covariates on the risk of first and second cardiovascular events. Thus it is important to extend such models by including risk equations for second cardiovascular events.

Commentary on the United Kingdom Prospective Diabetes Study outcomes model 2: Need for long‐term follow up and quality of life data in Asian patients

“…As expected, cardiovascular risks vary across study populations: the incidence of myocardial infraction and stroke per 1,000 person‐years were, respectively, 11.3 and 5.6 in the UK, and 13.5 and 12.1 in Sweden. By contrast, those of coronary heart disease and stroke were 7.6 and 7.1, respectively, in the Japanese study.…”

“…The incidence of a diabetic complication is viewed as a transition from a ‘no‐complication’ state to the disease state. The probabilities of each transition depend on the risk factors shown in Table , and the relationships between the probabilities and the risk factors are expressed as risk equations. Simulation by the UKPDS outcomes model 2 is carried out as the following steps on an annual cycle.…”

“…Among the models in Table , the UKPDS outcomes model 2, the JJ risk engine and the risk equations from the Swedish National Diabetes Register were developed by using individual patient data, but the others were constructed by synthesizing summary statistics reported in the literature, such as incidence rate and mean QOL value. The UKPDS followed more than 4,000 patients for the longest period, making it possible to simulate end‐stage events, such as second myocardial infarction and stroke.…”

The Michigan Model for Coronary Heart Disease in Type 2 Diabetes: Development and Validation

“…To our knowledge, none of the published, diabetes diseasestate simulation models, [20][21][22][23][24][25][26][27][28][29][30][31][32][33] including the recently published UKPDS Outcomes Model 2, 34 takes into account currently available medical and surgical treatments. For the general population, various CHD policy models exist.…”

Cost-effectiveness of add-on treatments to metformin in a Swedish setting: liraglutide vs sulphonylurea or sitagplitin

“…Another result from the validation of the IHE Cohort Model for Type 2 Diabetes was the importance of choosing sets of risk equations that match the decision context as regards time and place. In this cost-effectiveness analysis, we applied recently published Swedish macrovascular risk equations 32 . The one-way sensitivity analyses performed indicated that results and their interpretation were robust to changes in frequency of hypoglycemia associated with third-line insulin treatment, increasing initial BMI or a more invasive treatment programme where the second-line treatment is initiated at HbA1c 7% instead of starting at baseline values from trials (8.3% and 8.4%).…”