Background Glucocorticoid administration can lead to profound metabolic side-effects, including peripheral insulin resistance (IR), impaired glucose tolerance (IGT) and hyperglycemia and diabetes mellitus (DM). Homeostatic model (HOMA) is a validated method of IR evaluation.
Objectives To evaluate the role of C-peptide and modified HOMA-index in different carbohydrate metabolism disturbances (CMD) during glucocorticoid therapy.
Methods 165 patients were included: 53 patients with systemic lupus erythematosus (LE), 35 - with systemic vasculitis (SV); 67 - with chronic glomerulonephritis (CGN). 98 patients received glucocorticoid pulse-therapy (GC-PT) (1 course of 3 sessions) and 67 received oral GC. All patients underwent standard clinical and laboratory tests, glucose tolerance test (GTT), C-peptide evaluation, also HOMA-IR was calculated.
Results Oral GCT group revealed increased prevalence of CMD and DM – in 21 (31.1%) and 19 (28.4%) patients, respectively, compared to GC-PT group (p=0.038 and p=0.049, respectively). All patients receiving GC-PT (both with CMD and normoglycemia) demonstrated significant increase of C-peptide level and HOMA-IR index on during maximal blood glucose level, that is 4–6 hours after GC-PT (p<0.05). In patients with CMD HOMA-IR index normalization was insignificant; there were significant differences between the evaluated parameters before and after GC-PT, which indicates a more pronounced IR in these patients. C-peptide level in patients with DM, which developed after GC-PT, was significantly elevated compared to patients without CMD both at baseline (1050 vs. 410 pmol/l, respectively) and after GC-PT course (1796 vs. 1152 pmol/l, respectively) (p<0.05). During maximal blood glucose levels C-peptide was significantly elevated in patients with CMD, compared to patients without CMD (3170 vs. 2430 pmol/l; p<0.05), which substantiates the development of severe IR in patients with CMD and DM. HOMA-IR index in patients with DM was significantly elevated compared to patients without CMD at baseline (5.04 vs. 2.2; p<0.05), during maximal blood glucose level (15.2 vs. 5.84; p<0.05) and after GC-PT course (10.4 vs. 4; p<0.05) and in patients with IGT compared to patients without CMD – during maximal blood glucose levels (17.47 vs. 5.84; p<0.05) and after GC-PT course (9.67 vs. 4; p<0.05). C-peptide level was significantly elevated in patients receiving oral GC therapy and demonstrating impaired fasting glucose, IGT and DM compared to patients without CMD both at baseline (681.2, 877.9, 1106.1 vs. 384.7 pmol/l; p<0.05) and after OGTT (1411, 3296.7, 4981.7 vs. 839.2 pmol/l; p<0.05). C-peptide elevation after oral GTT was accompanied by a significant increase in HOMA-IR index compared to control group in patients with impaired fasting glucose, IGT and DM (6.37 vs. 9.04, 16.21, 19.84; p<0.05).
Conclusions CMD is more prevalent after oral GC therapy compared to GC-PT. In both groups C-peptide levels and HOMA-IR index were elevated in patients with IGT and DM both at baseline and after oral GTT, compared to patients without CMD and fasting glucose impairment, which proposes a presence of IR in that group of patients. HOMA-IR index can be utilized for the prognosis and early diagnostics of profound CMD in patients receiving intensive GC therapy and prolonged oral GC therapy.
Disclosure of Interest None declared