Effects of low or medium-dose of prednisone on insulin resistance in patients with systemic lupus erythematosus.

OBJECTIVES: To determine the effect of low (< or =7.5 mg/day; LD-PRD group) or medium (>7.5 mg/day; MD-PRD group) doses of prednisone over the past 4 months on insulin levels and insulin resistance (IR) in SLE patients. METHODS: SLE patients were categorised in prednisone non-users (No PRD) (n=41), LD-PRD (n=71) and MD-PRD (n=16) users. We compared insulin levels, presence of increased IR using homeostasis model assessment (HOMA index), metabolic syndrome (MetS), and other clinical, metabolic and inflammatory parameters in the 3 groups. A Spearman's rho test was used to identify independent associations between daily prednisone dose, HOMA index and insulin levels and other parameters, after adjusting for confounders. RESULTS: No differences in increased IR, HOMA index and insulin between No PRD and LD-PRD were found. In contrast, the MD-PRD group was younger (p=0.001) and had higher insulin (p=0.015), higher HOMA index (p=0.019) and increased IR (OR 5.8, 95% CI (1.7-20), p=0.007) in comparison with the LD-PRD group. The HOMA index strongly correlated with body mass index (BMI) (rs=0.460, p<0.001) but not with clinical activity or inflammatory state after adjusting for confounders. Prednisone dose correlated with the HOMA index and insulin but not with inflammatory parameters (erythrocyte sedimentation rate p=0.075) after adjusting for confounder. CONCLUSIONS: Daily medium-dose prednisone use (>7.5 mg/d) but not low-dose (< or =7.5 mg/d) use increased insulin levels and IR in SLE, which may contribute to increased CV risk experienced by these patients.