Characteristics of newly diagnosed systemic lupus erythematosus patients with or without kidney involvement: analysis of the National Database of Designated Intractable Diseases of Japan

CONCLUSION: In this nationwide cohort, nearly half of newly diagnosed Japanese patients with SLE had kidney involvement and showed a distinct pattern of systemic manifestations, autoantibody profiles, and treatment intensity. These findings provide important insights into the epidemiology and pathophysiology of kidney involvement in SLE in Japan.