Obesity increases the incidence of new-onset lupus nephritis and organ damage during follow-up in patients with systemic lupus erythematosus

Objective: This study explored the effects of obesity on clinical manifestations, disease activity and organ damage in Korean patients with systemic lupus erythematosus (SLE). Methods: We assessed 393 SLE patients annually for three consecutive years based on demographic information, clinical manifestations, laboratory findings and Physician Global Assessment, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI)-2000 and Systemic Lupus International Collaborating Clinics (SLICC) damage index (SDI) scores. Patients were grouped by body mass index (BMI): normal weight, BMI <23 kg/m²; overweight, 23 kg/m² ≤BMI <25 kg/m²; obese, BMI ≥25 kg/m². The impact of obesity on clinical outcomes was assessed using univariate and multivariate analyses. Results: Of the 393 patients, 59 (15.0%) were obese at enrollment. They had more comorbidities compared with non-obese patients, including diabetes, hypertension, hyperlipidemia and pulmonary hypertension. Nephritis at enrollment and newly developed nephritis during follow-up were more common (p = 0.002 and p = 0.002, respectively) and Physician Global Assessment and SDI scores were higher in these patients for three consecutive years (p = 0.017 and p = 0.039, respectively). Multivariate analysis revealed that obesity was significantly associated with development of nephritis during follow-up (odds ratio = 26.636; 95% confidence interval, 11.370–62.399; p < 0.001) and cumulative organ damage (odds ratio = 4.096; 95% confidence interval, 2.125–7.894, p < 0.001). Conclusions: The incidences of newly developed nephritis and cumulative organ damage were higher in obese SLE patients than in non-obese SLE patients.