Among subgroup analyses, FSTL1 was associated with calcific AS events in male patients (HR, 0.413; 95% CI, 0.199–0.857, P = 0.018), patients with younger age (HR, 0.171; 95% CI, 0.059–0.494, P = 0.001), patients with decreased lipoprotein a [Lp (a)] levels (HR, 0.349; 95% CI, 0.171–0.714, P = 0.004), and patients without eGFR decline (HR, 0.250; 95% CI, 0.082–0.759, P = 0.014) in the univariable Cox model. Here, FSTL1 is linked to aortic valve stenosis.