Predictive value of insulin autoantibodies for further progression of beta cell dysfunction in non-insulin-dependent...

The predictive value of insulin autoantibodies (IAA) was examined prospectively in 58 non-insulin-dependent diabetics (NIDDs) with and without IAA. The longitudinal changes in serum C-peptide (CPR) responses to 100 g oral glucose tolerance tests (OGTTs) as well as IAA and islet cell antibodies (ICA) in these subjects were followed up to 84 mo (mean 38 mo). Based on the positivity for IAA and ICA during the study, the subjects were subdivided into the following four groups; (a) persistently IAA- and ICA-positive subjects (Group 1, n = 7), (b) persistently IAA-negative and ICA-positive subjects (Group 2, n = 18), (c) persistently IAA-positive and ICA-negative subjects (Group 3, n = 3), (d) persistently IAA- and ICA-negative subjects (Group 4, n = 30). In Group 1 subjects serum CPR response to OGTT decreased significantly during the follow-up study (p less than 0.01), while in the remaining three groups, the response did not show any significant change. Blood glucose level during OGTT in Group 1 increased (p less than 0.01), while the values in remaining groups had no significant change. Four out of seven in Group 1 and 3 out of 18 in Group 2 progressed slowly to insulin-dependent state (p less than 0.07 Group 1 vs. Group 2). None of the subjects in Group 3 and Group 4 progressed to insulin-dependent state (p = 0.01 Group 1 vs. Group 4). The percent binding of labeled insulin and titer of ICA did not show any significant change among their positive groups during the study.(ABSTRACT TRUNCATED AT 250 WORDS)