The first hit you get when looking for the answer how ‘medical decision support’ is defined points to clinical decision support systems. The definition for wich is formulated as (attributed to Robert Hayward of the Centre for Health Evidence ):
Clinical decision support systems link health observations with health knowledge to influence health choices by clinicians for improved health care
The next logical step is to look at the topic of artificial intelligence in medicine.
However, in clinical practice there are more immediate and practical needs to have support for simpel calculation and lookup actions.