Prevention of the re-occurrence of a condition or prevention of a closely related condition arising from the pre-existing disease (secondary prevention) should not be coded within the 3 Prevention code group e.g. use of aspirin to prevent further adverse cardiovascular events or stroke in cardiovascular patients should be coded as 6.1 Pharmaceuticals and not 3.3 Nutrition prevention.
Prevention of a disease or condition within a specific patient group where the preventable disease is either unrelated to or may be a future sequela of the patient's current condition can be coded as primary 3 Prevention, e.g. prevention of cardiovascular disease in diabetic patients with no current cardiovascular disease diagnosis.
In circumstances where a study is focussed on preventing the side effects of a treatment, it would be appropriate to include a code in 3 Prevention and one from 5/6 Treatment. e.g study of a substance preventing side effects after chemotherapy for cancer would be coded 3.3 Nutrition prevention 50% and 6.1 Pharmaceuticals 50%.