Objectives SLE patients present with different clinical and serological manifestations according to the age at disease onset. However, it is not known whether there is an association between disease onset age and the clinical presentation of lupus nephritis (LN). Therefore, we investigated whether LN patients could be distinguished based on the time of disease onset and, if so, whether the groups differed in their clinical, laboratory features and long-term prognosis in ethnically homogeneous Korean patients.

Methods We enrolled 117 SLE patients with available clinical data at the time of renal biopsy for LN from the lupus cohort at Chonnam National University Hospital. We divided the LN patients according to the age at LN diagnosis into three groups [juvenile-onset LN (JLN), diagnosed at ≤18 years; adult-onset LN (ALN), diagnosed at 18–50 years; and late-onset LN (LLN), diagnosed at >50 years] and compared the baseline demographic, clinical, histological, and relevant laboratory findings. We also compared the treatment and long-term prognosis of LN according to those three groups.

Results Of the 114 LN patients, 20 (17.5%), 84 (71.8%), and 13 (11.1%) had JLN, ALN, and LLN, respectively. LLN patients were less educated than ALN and JLN patients (p <0.001). Hypertension and diabetes mellitus at the onset of LN were more common in LLN patients than ALN or JLN patients (p<0.001 and?p=0.037, respectively). Regarding the laboratory findings, LLN patients had a higher white blood cell count and lower eGFR than ALN or JLN patients (p<0.011 and 0.002, respectively). Histologically, LLN patients had more chronicity indices and a higher chronic score (p =0.006, p =0.019, p<0.001 and p<0.001, respectively). Anti-Ro antibodies were found more frequently in ALN patients and less frequently in JLN patients (p =0.024) and lower complement levels were more common in JLN patients and less common in LLN patients (p<0.011 and 0.002, respectively). During a mean follow-up of 76.5 months, the development of chronic kidney disease and death from any cause were higher in LLN patients than in JLN and ALN patients (p =0.028 and p =0.038, respectively).

Conclusions LN patients present with different clinical and serological manifestations according to age at disease onset. Interestingly, LLN patients had more chronicity at the time of renal biopsy, and more deterioration of kidney function and death on long-term follow-up, than JLN and ALN patients. Therefore, LLN patients should be monitored and managed carefully to avoid poor outcomes.

Disclosure of Interest None declared