Natural course of remission in IDDM during 1st yr after diagnosis

To describe the natural course of clinical remission in insulin-dependent diabetes mellitus (IDDM) when insulin dose is minimized without loss of target glycemia and to identify factors that predict clinical remission.

Ninety-five patients, who were placebo-treated control subjects in the Canadian-European multicenter randomized trial of cyclosporin A in recent-onset IDDM, were studied.

The mean insulin dose decreased during the first months after diagnosis, with a nadir at 3 mo, when 27% of the patients did not require insulin to maintain target glycemia. At 1 yr, 10% of patients still did not need insulin. Patients not receiving insulin who had glycosylated hemoglobin within the normal range were called remitters. Mean basal and glucagon-stimulated C-peptide values were significantly (P less than 0.025) higher in remitters than nonremitters at the start of the study. Therefore, all patients were divided into those with values above the mean stimulated C-peptide (0.4 nM) and those with values below the mean at entry. The probability of entering a remission with a stimulated C-peptide greater than 0.4 nM was 10 times as high (P less than 0.05) as for those with a stimulated C-peptide below this level. Surprisingly, the beginning and end of the remission were associated with neither major changes in C-peptide levels nor islet cell antibody and insulin-antibody titer. A more rapid loss of stimulated C-peptide occurred in patients who lacked HLA-DR3 and -DR4 (P less than 0.05 at mo 9).

This study shows a higher spontaneous clinical remission rate than expected during the 1st yr after diagnosis. Preserved beta-cell function at entry predicts a greater chance of entering a remission, and a more rapid loss of beta-cell function was seen in patients without HLA-DR3 and -DR4.