['We investigated whether anti-Smith (Sm) is associated with the outcome of kidney biopsy-proven lupus nephritis.', 'We retrospectively analyzed clinical, laboratory and histological results in 90 patients with kidney biopsy-proven lupus nephritis. We defined persistent administration of immunosuppressants for more than 3 months after the kidney biopsy as early poor outcome of lupus nephritis. We compared baseline variables and delta values of lupus nephritis-related variables between patients with and without anti-Sm. The independent predictive values for early poor outcome were analyzed using logistic regression analysis.', 'The median age was 32.0 years old, and 77 patients (85.5%) were women. Anti-Sm was found in 44 of 90 patients (48.8%). When we analyzed the differences in delta values of variables reflecting the kidney function or the early poor outcome between patients with and without anti-Sm, we found significant difference in the early poor outcome between the two groups (80.0% of patients having anti-Sm vs. 56.5% of those not having anti-Sm, P = 0.022). In multivariate logistic regression analysis, along with age and Systemic Lupus Erythematosus Disease Activity Index, the presence of anti-Sm increased the potential of the early poor outcome of lupus nephritis (odds ratio 2.870, 95% confidence interval, 1.033, 7.976, P = 0.043).'] Is anti-Sm associated with the early poor outcome of lupus nephritis?