Islet antibody testing could prevent complications by initiating insulin treatment much earlier. The results of a 12-year prospective follow-up study show a strong relationship between the presence of islet antibodies at diagnosis of adult-onset diabetes and future beta-cell function.
in the June issue of the journal Diabetes, Dr. Henrik Borg from Lund University, Malmo and Swedish colleagues write, that the study argues for repeated islet antibody testing beginning at diagnosis in patients with adult-onset diabetes,
They previously found that a group of adult diabetics with islet cell antibodies had high levels of glutamic acid decarboxylase 65 antibodies (GADA) and/or IA-2 antibodies at diagnosis, and more severe beta-cell dysfunction 5 years after diagnosis, than diabetics with lower GADA levels.
Dr. Borg’s group now reports that, in107 patients, the vast majority of those with GADA and/or islet cell antibodies at diabetes diagnosis developed complete beta-cell failure (undetectable fasting P-C-peptide) after 12 years, regardless of age.
"Patients with isolated GADA positivity had some preserved function 5 years after diagnosis of diabetes; however, most of them (80%) had developed beta-cell failure 12 years after diagnosis," the authors note.
By contrast, fasting P-C-peptide levels remained unchanged over the 12 years in antibody-negative patients indicating preservation of beta-cell function.
Only rarely did antibodies develop after diagnosis, according to Dr. Borg’s team. They found that islet cell antibodies, but not GADA or IA-2 antibodies, which developed after diagnosis in roughly 5% of the originally islet cell antibody-negative, mostly overweight patients, predicted a decline in beta-cell function.
Dr. Borg’s group concludes the findings strongly support islet antibody testing at diagnosis in most patients. Noting that such testing is costly, they suggest the following strategy: a primary screen for GADA followed by a second test for IA-2 antibodies in GADA-positive patients with low GADA levels "to improve the prediction of a fast progression to beta-cell failure." Diabetes 2002;51:1754-1762.