Comparison of clinical, serological, and prognostic differences among juvenile-, adult-, and late-onset lupus nephritis in Korean patients.

We investigated whether lupus nephritis (LN) patients could be distinguished based on the time of disease onset and, if so, whether the groups differed in their clinical and laboratory features and long-term prognosis in ethnically homogeneous Korean patients. We enrolled 117 systemic lupus erythematosus patients with available clinical data at the time of renal biopsy of LN. Sociodemographic, clinical, and laboratory data and concomitant diseases were evaluated at the time of renal biopsy. We divided LN patients, according to 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 demographic, clinical, histological, and laboratory findings. We also compared treatment and long-term prognosis of LN. Of the 117 LN patients, 20 (17.8%), 84 (71.3%), and 13 (10.9%) were JLN, ALN, and LLN patients, respectively. LLN patients showed higher white blood cell counts and lower estimated glomerular filtration rate than ALN or LLN patients. LLN patients had higher chronicity indices and scores. Anti-Ro antibodies were found more frequently in ALN patients, and lower complement levels were more common in JLN patients. During a mean follow-up of 76.5 months, development of chronic kidney disease and death were higher in LLN patients than in JLN and ALN patients. LLN patients showed higher chronicity indices and deterioration of kidney function and death in long-term follow-up compared with JLN and ALN patients. Therefore, LLN patients should be carefully monitored to avoid poor outcomes.