Age, Male Sex Associated With Development of Lupus Nephritis

A study in Rheumatology investigated factors associated with kidney involvement in patients with systemic lupus erythematosus (SLE).

From a 570-patient cohort, patients were monitored for lupus nephritis (LN), which was defined by kidney histology and/or classification criteria. Those who presented with or developed LN were compared with the rest of the cohort who did not have kidney involvement in terms of demographic and clinical characteristics at baseline.

Overall, 59 patients presented with LN at baseline and 66 developed LN during the follow-up period. The collective incidence of LN was 21.9%.

Age at SLE diagnosis and sex were found to be associated with developing LN. Males were more likely to develop kidney involvement; the adjusted hazard ratio (aHR) for male sex was 4.31 (95% CI, 1.82-10.20). For those who were diagnosed with SLE below the age of 26, the aHR for developing LN was 3.71 (95% CI, 1.84-7.48). Additionally, a high anti-double-stranded DNA titer was associated with developing LN (aHR, 2.48; 95% CI, 1.03-5.97). There was a non-statistically significant association between low levels of C3 and/or C4 and development of LN (aHR, 2.24; 95% CI, 0.83-6.05; P=.11).

The authors noted that a combination of these factors at the time of SLE diagnosis was associated with an almost 90-fold risk of developing LN when compared with serologically inactive, older, female patients (aHR, 88.77; 95% CI, 18.75-420.41), “signifying a very high-risk group.” These findings remained after independent validation with another lupus registry.

In summary, “Male sex, younger age, and serologic activity at SLE diagnosis are strongly associated with subsequent kidney involvement,” the authors wrote. In this subset of patients, they called for “vigilant surveillance” along with the consideration of disease-modifying drugs early in the course of treatment.