GDF2 and hypertensive disorder: According to the concentration of BMP9 in HTN, CHD and HTN + CHD patients, it is divided into quartile (quartile 1, < 31.80 ng/L, quartile 2, 31.81–46.44 ng/L, quartile 3, 46.45–62.80 ng/L, quartile 4, > 62.80 ng/L for HTN; quartile 1, < 27.24 ng/L, quartile 2, 27.25–42.25 ng/L, quartile 3, 42.26–74.71 ng/L, quartile 4, > 74.71 ng/L for HTN + CHD and quartile 1, < 24.98 ng/L, quartile 2, 24.99–54.95 ng/L, quartile 3, 54.96–70.86 ng/L, quartile 4, > 70.86 ng/L, respectively).