Carotid Intima Media Thickness as a Marker of Atherosclerotic Burden in Patients with Systemic Lupus Erythematosus: A Cross-sectional Study from a Tertiary Care Centre of Eastern India

Introduction: Systemic Lupus Erythematosus (SLE) patients have an increased burden of atherosclerosis leading to adverse Cardiovascular (CV) events. Alterations in endothelial function, dysregulated immune system and increased oxidative stress are implicated in their development and progression. Carotid artery ultrasound is recommended to assess and follow progression of subclinical atherosclerosis and correlate with traditional/non traditional CV risk factors in SLE.

Aim: To study the correlation between Carotid Intima Media Thickness (CIMT), traditional/non traditional CV risk factors in SLE.

Materials and Methods: The hospital-based, descriptive, cross-sectional study was conducted in the Department of Internal Medicine, Medical College Kolkata, Kolkata, West Bengal, India, from April 2019 to August 2020. Patients with SLE, diagnosed by Systemic Lupus International Collaborating Clinics (SLICC) 2012 criteria, aged >12 years, irrespective of therapy status, were recruited by consecutive sampling. Subjects were classified as Lupus Nephritis (LN) and Lupus without Nephritis (LWN). Demographic data, parameters to define SLE (SLICC 2012 criteria), blood parameters like lipid profile, fasting plasma glucose, anti-Double stranded Deoxyribose Nucleic Acid antibody (anti-dsDNA Ab), C3/C4 levels, 24 hour urine protein values, haemoglobin, C-reactive Protein (CRP), serum homocysteine and Carotid Intima Media thickness as measured by Ultrasonography (USG) doppler study, duration of disease and medication history were considered as study variables. Statistical analysis was done by using Z-test, t-test, Analysis of variance (ANOVA), Chi-square test (for categorical data) and other non parametric statistical tests and correlation tests, wherever applicable. A p-value <0.05 was considered to be statistically significant.

Results: Fifty five SLE patients were studied. Subgroup analysis was performed between LN (n=36) and LWN (n=19). The mean age of the study subjects was 33 years with mean disease duration of 4.6 years. LN patients had longer disease duration, younger age of disease onset and longer duration of steroid usage. The mean systolic Blood Pressure (BP) was significantly higher in LN subgroup. Framingham Risk Scores (FRS) was positively correlated with duration of SLE disease and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI-2K) scores and duration of steroid therapy. The mean CIMT of the study population is 0.91 mm with 10.9% plaque prevalence whereas, mean CIMT of the LN subgroup and LWN subgroup was 1.02±0.27 mm and 0.86±0.3 mm, respectively; however no statistically significant difference in CIMT was observed between two subgroups. CIMT positively correlated with anti-dsDNA Ab levels, FRSs, anaemia, SLE Disease activity scores, 24 hour urine protein, duration of steroid usage, serum creatinine and CRP. No correlation between CIMT and age of subjects, Fasting Plasma Glucose (FPG), Triglycerides (TG) serum homocysteine was observed.

Conclusion: Systemic lupus erythematous patients have a high atherosclerosis burden and are at increased risk of adverse CV events. LN patients, early age of lupus onset, longer disease duration with prolonged steroid therapy, significant proteinuria, higher anti-dsDNA Ab levels and hypocomplementemia were observed to have higher mean CIMT and plaque formation.