Improving life expectancy and decreasing the incidence of complications associated with type 2 diabetes: a modelling study of HbA1c targets

To project the long-term clinical and cost outcomes that accompany predefined improvements in glycaemic control in patients with type 2 diabetes. A peer-reviewed, validated, non-product-specific Markov model of type 2 diabetes was used to project the long-term clinical and cost outcomes associated with three HbA1c reduction scenarios (vs. no reduction): (i) decreasing mean HbA1c from 9.5% to 8.0%; (ii) from 8.0% to 7.0%; and (iii) from 7.0% to 6.5%. A typical baseline US type 2 diabetes cohort derived from National Health and Nutrition Examination Survey data was simulated over a lifetime horizon (35 years). Incidence of diabetes-related complications and costs (2005 USD) were accounted based on published data. Discount rates (3% per annum) were applied to clinical benefits and costs. Sensitivity analyses were performed. Stepwise reductions in HbA1c as an independent variable correlated with delayed time to diabetes-related complications and a reduced cumulative incidence of complications, including cardiovascular, renal and neurologic comorbidities. Related costs also decreased. Reductions in both poorly- (9.5-8.0%) and better-controlled (7.0-6.5%) patients produced incremental gains in undiscounted life expectancy (LE) [1.06 (0.31) and 0.32 (0.34) years [mean (SD)], respectively]. Similar improvement patterns were observed in quality-adjusted life expectancy (QALE). Benefits from sequential reduction scenarios, when aggregated, exhibited the most dramatic effect. Improved glycaemic control was associated with reductions in complication rates and costs, as well as increased LE and QALE among type 2 patients. These data illustrate the long-term importance of reaching normoglycaemia and support intensified HbA1c control as a cornerstone of effective long-term type 2 diabetes management.