Beta cell function in insulin-treated non-insulin-dependent diabetic patients

Non--insulin-dependent diabetes mellitus (NIDDM) patients, 94 in number, who were treated with insulin for various reasons for periods ranging from 2 to 10 years, were investigated to study the effect of long-term insulin therapy and also the effect of anti-insulin antibodies on the beta cell function. Insulin antibody titer and the stimulated C-peptide (CP) did not correlate with the duration of insulin therapy, dose of insulin, or the severity of hyperglycemia. The antibody titers were low in 45%, moderate in 10%, and high in 45%; no correlation was found between the antibody titers and the CP values. Satisfactory control of hyperglycemia was obtained in 54 patients after change of treatment to oral hypoglycaemic agents (OHA). The other 40 patients required continued insulin therapy. The initial CP values were similar in both the groups before initiating the new therapeutic patterns. Those who responded to OHA showed improved CP values on follow-up. The beta cell response to exogenous insulin is heterogeneous in NIDDM patients. In many patients, adequate preservation of beta cell function is present even after long-term insulin therapy. Many of them respond to OHA. Insulin antibodies do not influence the secretory status of the beta cells in NIDDM patients.