Modeling disease progression in newly diagnosed type 2 diabetes
Type 2 diabetes (T2DM) is a progressive disease, which is primarily characterized by a decline in {beta}-cell function and worsening of insulin resistance. Unfortunately, most interventions (lifestyle, diet, and therapeutic agents) for T2DM only provide a transient restoration of {beta}-cell function and the progression is inevitable once it starts. To understand the natural progression of T2DM, a mechanistic model was developed to quantitatively characterize the dynamic interactions among {beta}-cell function, plasma fasting glucose (PFG), fasting insulin (FI), and the degree of insulin resistance, starting from an early stage of T2DM over up to 8 years. The model was validated using clinical data to optimize the disease parameters. The restoration and deterioration rates of {beta}-cell function were both predicted as 84.5 %/year and 1.10 /year for early stages of T2DM. The model predicted a positive correlation between the initial level of {beta}-cell function at diagnosis and its maximum restoration potential, underscoring the importance of early diagnosis and intervention. After the treatment, {beta}-cell function could be temporarily restored within several months, which has a long-term benefit in glycemic control. The maximal tolerated PFG level that permits {beta}-cell function restoration was predicted to be around 8.33 nM; and the temporal restoration of {beta}-cell function would be unlikely at a PFG level above this threshold. The intrinsic deterioration rates of {beta}-cell function and insulin resistance were both critical factors for long-term glycemic control. In conclusion, our model provides a quantitative analysis of the natural disease progression in T2DM and yields insights into factors that are critical for long-term glycemic control.