Notably, the correlation analysis between nutritional indices and SLE activity-related measures revealed that the CONUT score and PNI were better correlated with the SLEDAI-2K, which is the most widely used index to assess global SLE disease activity, along with WBC and platelet counts, C3, C4, and anti-dsDNA levels, urinary P/Cr ratio (which is a laboratory component of the SLEDAI-2K), and the activity index as determined through renal biopsy. Here, C4A is linked to systemic lupus erythematosus.