In addition, growth differentiation factor-15 (GDF-15) (16) and lactate (17), creatinine (18), hyponatremia (19), and even copeptin, a surrogate marker of antidiuretic hormone (20), have also been found to be used for risk stratification in patients with APE, and these factors need further validation. The gene discussed is GDF15; the disease is Hyponatremia.