Background Previous studies suggest that ethnicity influences the clinical phenotype in systemic lupus erythematosus (SLE), with lupus nephritis (LN) being more frequent in non-Caucasians. However, there are scarce data regarding prevalence of LN in South-Asian population (Indians, Pakistani, Sri Lanka, or Bangladeshi).

Objectives This study aimed to compare the prevalence of LN between lupus patients of different ethnicities, and to compare demographics and disease characteristics between LN patients.

Methods This is a retrospective chart review study of 100 lupus patients followed from 2013 to 2017 at Wexham Park Hospital, a large district hospital in Southern England. The patients were categorised into four ethnic groups Caucasians, South-Asians, Blacks and Others (mixed race, Orientals, Arabs). LN prevalence, demographic and clinical data were compared using Fisher/Chi-Square tests for categorical variables and Wilcoxon test for continuous variables.

Results Of 100 patients in the study sample, 51% were Caucasians, 31% were South-Asians, 11% were Blacks and 7% had other ethnicities. Mean age was 48 yo and 90% were females. Prevalence of LN was 26% in the full study sample and 24%, 16%, 64% and 57%, respectively, among Caucasians, South-Asians, Blacks and Others. LN prevalence was significantly lower in Caucasians vs Blacks (p=0.01), South-Asians vs Blacks (<0.01) and South-Asians vs Other (p=0.02). Among patients with LN, mean age was lower in South-Asians and Blacks, than Caucasians and Others (44 and 45 yo vs 52 and 51 yo). Blacks appear to include more males (43% vs <25% in the other groups). Renal biopsy, available for 22/26 LN patients, suggested Class II predominance in Caucasians (44% vs 33% in the other groups). Proliferative LN (Class III and IV) was confirmed in 7 patients, without significant predominance in any ethnic group. Specific lupus autoantibodies (anti-dsDNA Ab and/or antiSm Ab) were found in 64% Caucasians, 75% south-Asians, 86% Blacks and 75% others with LN.

Conclusion In our cohort, prevalence of LN in South-Asians was lower than in Blacks, but not statistically different comparing with Caucasians. However, South-Asians and Blacks with LN were younger than Caucasians. These results should be re-examined in larger similar multi-ethnic cohorts.