Insulin Resistance in Patients with Lupus Nephritis: Association to Cardiovascular Risk Factors, Disease Activity, and Subclinical Atherosclerosis

Abstract Background: Insulin resistance is one of the crucial risk factors for cardiovascular disease (CVD) insystemic lupus erythematous (SLE). Lupus nephritis represents one of the most serious complications of SLE with increased risk of CVD. No previous studies evaluated insulin resistance in Lupus nephritis patients. Aim of Study: The study aimed to evaluate insulin resist-ance in patients with lupus nephritis and assess its relationship to traditional cardiovascular risk factors, disease activity, damage index and subclinical atherosclerosis. Material and Methods: We enrolled 90 patients had SLE including 10 males and 80 females. SLE patients were divided into 45 patients had lupus nephritis based on renal biopsy and 45 patients had no evidence of lupus nephritis. One hundred healthy subject sex and age matched was served as the control group. Patients were recruited from the Rheumatology and Immunology Clinic of the Internal Medicine Department, Kasr Al-Ainy Hospital, Faculty of Medicine, Cairo University. Fasting (blood sugar, serum lipids, oxLDL, and insulin) were measured. Homeostasis model assessment of insulin resistance (HOMA-IR) were calculated and Carotid intima media thick-ness (CIMT) was measured in all patients. Our data was expressed as mean ±  SEM, The correlation between variables was evaluated using Spearman's rank correlation coefficient test. Linear regression analysiswas done to explore the asso-ciated factors with insulin resistance. Results: There was significant increase in HOMA-IR in lupus nephritis patients with mean (11.7±1.1) compared to non-nephritis patients (4.4±0.4), p<0.001. HOMA-IR was significantly correlated to BMI (p=0.01), FBS (p=0.001), TC (p=0.001), TG (p=0.003), LDL-C (p=0.01), oxLDL (p=0.03), CRP (p=0.04), serum creatinine (p<0.001), urine albumin creatinine ratio (p<0.001), CIMT (P= 0.03), lupus activity index (SLEDAI) (p=0.02), damage index (SLICC/ACR) (p= 0.04) and negatively correlated to albumin (p=0.04) and HDL-C (p<0.001). After linear regression analysis, serum creatinine (p=0.04), and SLICC/ACR (p=0.02) were still significantly associated to insulin resistance in lupus nephritis patients. Conclusion: Patients with lupus nephritis were at increased risk of insulin resistance than non-nephritis SLE patients andsignificantly associated to traditional CVD risk factors, subclinical atherosclerosis, disease activity and damage index. Increase in serum creatinine and disease damage index were significant associated factors for insulin resistance in lupus nephritispatients. Early introduction for the suitable treatment modality in patients with lupus nephritis could ameliorate cardiovascular disease progression.