Progression to and prevention of diabetes: Disparity of impaired fasting glucose and impaired glucose tolerance

It is well established that individuals who have prediabetes either impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) have high risk to develop diabetes. However, it is unclear whether the rate of progression to diabetes is different between these two categories. Lifestyle modification has been recommended for diabetes prevention in these high-risk groups. However, given the differences in their pathophysiology, it is possible that these subtypes of prediabetes condition may have different responses to lifestyle modification. The present review was to summarize the risk of progression to diabetes and the effectiveness of lifestyle intervention for diabetes prevention in individuals who have isolated IGT or isolated IFG or combined. The risk of progression to diabetes is highest in combined IFG and IGT subtype. Individuals who have isolated IFG by the American Diabetes Association criteria (100 to 125 mg/dl) has lower risk of progression to diabetes than those with World Health Organization criteria (110 to 125 mg/dl) and the latter has similar or higher risk of incident diabetes than those with isolated IGT. Lifestyle modification is most effective in individuals with IGT (with or without IFG) but is less effective in those with isolated IFG. In conclusion, The risk of progression to diabetes and the effectiveness of lifestyle intervention for diabetes prevention are disparate between prediabetes subtypes. Given the paucity of diabetes prevention data in individuals with isolated IFG, more studies dedicated to this subtype is required. Keywords: Impaired fasting glucose, Impaired glucose tolerance, Prediabetes, Type 2 diabetes, Lifestyle intervention, Diabetes prevention DOI: doi.org/10.35755/jmedassocthai.2020.08.11222 Received 26 Feb 2020 | Revised 7 May 2020 | Accepted 8 May 2020