OBJECTIVES: The United Kingdom Prospective Diabetes Study Outcomes Model (UKPDS-OM2) is widely used for type 2 diabetes (T2D) risk assessment, drawing from two decades of data encompassing 5,000+ patients. However, its applicability to non-UK patients, particularly in Asian countries like Japan, remains uncertain. Local decision-makers often prefer local risk equations. Accordingly, the IHE-DCM-T2 model was augmented with The Japan Diabetes Complications Study/Japanese Elderly Diabetes Intervention Trial risk engine (JJRE). Despite being estimated with a smaller sample and fewer follow-up years, and considering fewer outcomes compared to UKPDS-OM2, JJRE relies exclusively on data from Japanese patients. The objective was to inform Japanese decision-makers on the tradeoffs between local applicability and robustness of risk equations by comparing key outcomes when using JJRE and UKPDS-OM2 equations for Japanese T2D patients.

METHODS: Using the IHE-DCM-T2 model, we simulated the impact of DPP-4 inhibitors vs. biguanides over 40 years for a Japanese T2D cohort and for subgroups based on sex and age. HbA1c lowering was sourced from a Japanese RCT, while unit costs (¥140.53=1$) and QALY weights were sourced from published Japanese literature. A public payer perspective was adopted, and results were discounted 2% annually. Key health, cost, and cost-effectiveness outcomes were compared across the risk engines.

RESULTS: While complication rates varied, JJRE consistently generated longer life expectancy than UKPDS-OM2 in both treatment arms for the population and subgroups. JJRE-estimated ICERs were $32,852 for the total population, higher than UKPDS-OM2's $23,761. UKPDS-OM2-derived ICERs were more sensitive to age, ranging from $8,374 to $40,188.

CONCLUSIONS: This study cannot conclusively establish the superiority of either risk engine, but it highlights critical differences. Notably, JJRE's longer life expectancy aligns with longer life expectancy in Japan. The choice of risk engine significantly influences key health and economic outcomes, including the ICER. Japanese decision-makers must weigh these implications when reviewing diabetes modeling applications.