Patel M et al. (2006) The prevalence and incidence of biopsy-proven lupus nephritis in the UK: evidence of an ethnic gradient. Arthritis Rheum 54: 2963–2969

Estimates of the prevalence and incidence of lupus nephritis in the UK have revealed striking ethnic variation: white patients with systemic lupus erythematosus (SLE) had the lowest prevalence of lupus nephritis, followed (in ascending order) by Indo-Asian, Afro-Caribbean, and Chinese patients. Lupus nephritis is a major complication of SLE, with substantial morbidity and mortality; this study supports previous findings that SLE is not only more common, but also has a worse prognosis, in nonwhite compared with white ethnic groups.

Patel and colleagues identified 208 individuals (176 women) with biopsy-proven lupus nephritis in the northwest of England during 2001. Data from the 2001census indicated a prevalence of lupus nephritis of 4.4 cases per 100,000 of the population. The prevalence and incidence of lupus nephritis were markedly higher in women than in men (prevalence, 7.1 versus 1.4 cases per 100,000; incidence, 0.68 versus 0.09 cases per 100,000), a pattern repeated in all ethnic subgroups; however, more men had lupus nephritis than expected. Patel et al. suggest that male sex (in patients with SLE) confers an increased risk of lupus nephritis. The prevalence of lupus nephritis was highest in Chinese patients (65.5 cases per 100,000), although only 13 Chinese patients were included in the study.

Notably, peak prevalence of lupus nephritis occurred earlier in Afro-Caribbean and Chinese women than in white and Indo-Asian women (at age 20–39 years, versus 40–59 years). In men, prevalence increased with advancing age in all ethnic groups.

Patel and colleagues estimate that 10% of white patients, 27% of Indo-Asian patients, and 58% of Afro-Caribbean patients with SLE develop lupus nephritis.