Background C-peptide reflects the level of endogenous insulin secretion and enables the evaluation of pancreatic β-cell function.

Objectives To evaluate the influence of glucocorticoid pulse-therapy (GT PT) on the level of plasma C-peptide in patients with lupus erythematosus (LE) after the infusion in short-term.

Methods The study included 20 patients (men – 2, women - 18) with LE aged 18-61 years (mean age 37,56±13,02) and duration of disease 1 to 12 years (mean 3,92±3,81). GC PT consisted of intravenous infusion of 600-1000 mg of prednisone a day with 250 ml of 0,9% isotonic solution for 3 consecutive days (1 course of 3 infusions). Total dose for a course was 1800-3000 mg/day. For the evaluation of C-peptide plasma levels we used enzyme-linked immunosorbent assay (ELISA) for the evaluation of C-peptide proinsulin in human blood and plasma. Reference range: 0,9 – 4,0 ng/ml. We performed the evaluation of glucose levels in all patients before the start of PT and at 2, 4, 6,10, 24, 48 and 72 hours after the infusion, and in patients with abnormal blood glucose level at 72 hours after the infusion the evaluation was continued until normalization of blood glucose levels. The evaluation of C-peptide level was performed before the start of PT infusion and at the climax of glycemia.

Results Mean C-peptide level before the start of GC PT was 1,9±1,35 mmol/l (0,55 to 4,0 ng/ml) All patients demonstrated an increase of blood glucose levels after the course of GC PT, reaching maximum 4 hours after the start of the infusion - 12,1±3,26 ng/ml (7,3 to 22,2 ng/ml). At the peak glycemia after GC PT the level of C-peptide was 8,84±4,19 ng/ml (2,56 to 16,11 ng/ml), demonstrating a 4,7-fold increase of C-peptide level.

Conclusions GC PT in LE patients is associated with an elevation of blood glucose an C-peptide levels reaching peak values at 4 hours after the start of the infusion and remaining elevated for 2 or more days. The increase of C-peptide level reflects the increase of endogenous insulin production, which accompanies the increase of blood glucose level, pointing to possible insulin resistance, which can be a predictor of profound carbohydrate metabolism disturbance. Our data substantiate the need to perform additional blood glucose evaluation in this group of patients.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.4328