a decreasing trendp < 0.0001
The concentration of β2-MG showed an increasing trend with medication for any disease ( p = 0.03), history of OCE ( p = 0.03), and period of OCE ( p = 0.01), and eGFR and age ( p < 0.0001), whereas it exhibited a decreasing trend with smoking history ( p < 0.0001), history of OCE ( p < 0.0001), and period of OCE ( p < 0.0001).