We found a significant inverse association between higher SII values and lower Klotho concentrations in serum, and the association was not affected by age, sex, race/ethnicity, BMI, diabetes, CKD, hypertension, COPD, CHD, or hyperlipidaemia (all P for interaction ≥ 0.05). The gene discussed is KL; the disease is chronic obstructive pulmonary disease.