Do patients have the right to refuse medical treatment?

In it they stated that the United States Constitution would grant a competent person a constitutionally protected right to refuse life-saving medical treatment Whether for financial, spiritual or religious reasons, a patient has the ultimate say over what is done to his or her body.

Yes they can such as blood transfusion doctors cannot force you too. Unless you are a child and your parents refuse the medical treatment, in some states they will take your child way if refused it.