Diabetes mellitus involving the heart and kidneys may cause swelling of the feet, in addition to diabetes mellitus patients with swelling of the feet also need to exclude other factors caused by cardiogenic edema, renal edema and edema caused by liver disease. 1. Diabetes mellitus: Diabetes mellitus may involve the kidneys and the heart as the disease progresses, and lead to hypertension, foamy urine, edema and other corresponding clinical symptoms, so diabetes mellitus may lead to patients with foot edema symptoms. 2. Cardiogenic edema caused by other reasons: in addition to diabetes, if the patient also has rheumatic immune diseases, infectious diseases and other causes of cardiac failure, the patient may be due to the obstruction of blood reflux leading to edema in the feet. 3. Other causes of nephrogenic edema: In addition to diabetes mellitus, if the patient also exists in nephrotic syndrome, glomerulonephritis and other diseases, it is also possible that the glomerular filtration dysfunction leads to the accumulation of water in the patient’s body, which leads to edema in the feet. 4. Liver disease: patients with viral infections, drugs and other factors leading to impaired liver function, due to the body’s albumin synthesis obstacles, plasma colloid osmotic pressure is reduced and lead to swelling of the feet. There may be other reasons for diabetic patients to have swollen feet, and it is recommended that patients go to the endocrinology department of regular hospitals and other related departments to further improve the examination to make a clear diagnosis.