Beta-Cell Dysfunction and Insulin Resistance Among Italian Patients With Type 2 Diabetes (MK-0000-113)

Primary outcomes

1. Change From Baseline in Homeostatic Model Assessment Fasting Beta Cell Function (HOMA % B) at 4 Years

   Time frame: Baseline and 4 years

   HOMA is a method used to quantify insulin resistance (a condition in which natural hormone insulin becomes less effective in lowering blood sugars) and beta-cell (specialized cells in the pancreas producing insulin) function. HOMA uses fasting plasma insulin and glucose concentrations to estimate steady state pancreatic beta cell function (%B) as a percentage of a normal reference population (normal young adults). The normal reference population was set at 100%. HOMA%B was defined as 20 x fasting insulin (mU/L)/fasting glucose (mmol/L) - 3.5.

2. Change From Baseline in Proinsulin/Insulin (PI/I) Ratio at 4 Years

   Time frame: Baseline and Year 4

   Proinsulin is the prohormone precursor to insulin made in the beta cells of the islets of Langerhans, specialized regions of the pancreas. A raised proinsulin-to-insulin ratio due to impaired processing of proinsulin is an early marker of beta cell dysfunction. Beta-cell dysfunction was evaluated by calculating the PI/I ratio, which estimates the capacity of beta cells to convert proinsulin to insulin and may represent an acceptable method to indicate the degree of beta-cell secretion.

3. Homeostatic Model Assessment Fasting Beta Cell Function (HOMA % B) According to Quartiles of Proinsulin/Insulin (PI/I) Ratio

   Time frame: Baseline

   HOMA is a method used to quantify insulin resistance (a condition in which natural hormone insulin becomes less effective in lowering blood sugars) and beta-cell (specialized cells in the pancreas producing insulin) function. HOMA uses fasting plasma insulin and glucose concentrations to estimate steady state pancreatic beta cell function (%B) as a percentage of a normal reference population (normal young adults). The normal reference population was set at 100%. HOMA%B was defined as 20 x fasting insulin (mU/L)/fasting glucose (mmol/L) - 3.5. Beta-cell dysfunction was evaluated by calculating the PI/I ratio, which estimates the capacity of beta cells to convert proinsulin to insulin and may represent an acceptable method to indicate the degree of beta-cell secretion.