A study of 982 patients with RA from the NHANES 2007–2016 identified a remarkable inverse association between the SII and serum levels of soluble Klotho protein (42), and a significant inverse correlation was observed between the SII and serum Klotho protein—an anti-aging, anti-inflammatory molecule secreted mainly by the kidneys and parathyroid glands (43, 44). The gene discussed is KL; the disease is rheumatoid arthritis.