Coefficient of β-cell failure in patients with type 2 diabetes treated with pioglitazone or acarbose

Aim: A new method of assessing the coefficient of failure of pancreatic beta-cells from any index of glycaemia has been proposed. This method of analysis has been used to assess data on HbA1c and fasting glucose concentrations from a randomised study comparing pioglitazone with acarbose. Methods: Patients were treated for 26 weeks with either pioglitazone 45 mg once daily or acarbose 300 mg/day as 3 equal doses. Plasma HbA1c concentration was measured every two months and fasting glucose was measured monthly. The coefficient of failure was determined for each patient from the slope of the least squares regression line over time. Results: The coefficient of failure from HbA1c was -2.65 +/- 2.13%/year with pioglitazone and -1.25 +/- 3.11%/year with acarbose, indicating improved beta-cell function in each case. The coefficient of failure was improved to a significantly greater extent with pioglitazone (P < 0.001). Coefficient of failure from fasting blood glucose also showed a greater improvement with pioglitazone (-53.1 +/- 95.0 mg/dl/year) than with acarbose (-29.9 +/- 142.5 mg/dl/year; p = 0.049). Conclusion: The coefficient of failure showed a significantly greater improvement of beta-cell function with pioglitazone than with acarbose during 26 weeks of treatment.