Beta cell function in long term NIDDM (type 2) patients and its relation to treatment.

Pancreatic beta cell function was assessed by estimation of fasting and post prandial plasma C-peptide in 183 non-insulin dependent diabetic patients, who were treated with oral hypoglycaemic drugs, for more than 10 years. One-hundred-and-forty-one patients, continued to respond to oral hypoglycaemic agents (Group I) and in 42 the control was not satisfactory and had to be changed over to insulin (secondary failure, Group II). Significant beta cell reserve (PP CP greater than or equal to 0.6 pmol/ml) was present in 89 out of 183 patients (48%) and 83 (93%) of them responded to oral hypoglycaemic agents. Among the 94 patients with low beta cell reserve, 58 (62%) were on oral hypoglycaemic agents and the other 36 (38%) were on insulin. Of the 42 patients with secondary failure to the oral drugs, 36 (86%) had low C-peptide while 6 (14%) had significant C-peptide values. Secondary failure to oral hypoglycaemic agents can also occur in spite of good beta cell reserve. Beta cell reserve was not correlated either to the duration of diabetes or the age at diagnosis of the patients.