To elucidate whether clinical features and the weighted genetic risk score (wGRS) were associated with the presence of lupus nephritis (LN).
We retrospectively divided patients with systemic lupus erythematosus (SLE, n = 1,078) into biopsy-proven LN (n = 507) and non-LN groups (non-LN, n = 571). Baseline clinical features, serologic markers, and the wGRS were collected. The wGRS was calculated from 112 non-HLA loci and HLA-DRĪ²1 amino acid haplotypes for SLE. Associations among clinical features, wGRS, and the presence of LN were identified.
In the multivariate analysis, patients with LN were younger at diagnosis (odds ratio (OR) = 0.97, p < 0.001), had more pleuritis (OR = 2.44, p < 0.001) and pericarditis (OR = 1.62, p = 0.029), had a higher detection rate of anti-double stranded deoxyribonucleic acid (anti-dsDNA antibodies, OR = 2.22, p < 0.001), anti-Smith antibodies (anti-Sm antibodies, OR = 1.70, p = 0.002), low level of complement (OR = 1.37, p = 0.043) and absence of antiphospholipid antibodies (aPL antibodies, OR = 1.60, p = 0.002), and had higher wGRS (OR = 1.16, p = 0.012). Mediation analysis suggested that anti-Sm antibodies and low complement could be mediators in the relationship between high wGRS and the presence of LN.
Onset age, pleuritis, pericarditis, several serologic markers, and wGRS were associated with the presence of LN. Anti-Sm antibodies and low complement appeared to mediate the indirect relationship between wGRS and the presence of LN.