It occurs when the pancreas is no longer able to make insulin or when the body is not able to produce insulin, it allows your body to use glucose for energy. Glucose is a type of sugar found in many carbohydrates. , when the body can not use insulin in its proper way it means the patient is diabetic.it is a chronic disease that leads to death.it damages the immune system of the whole body. Patients suffering from this disease could not fight against any other disease.