If you had a long list a table with a dotablelookup would work. This would allow you to not have to change code to update existing.
The code would look something like this.
var processPatientClass = StringUtils.equalsIgnoreCase(qie.doTableLookup(message.getNode('PV1-3'), 'notFound', 'tableName', 'sourceColumn', 'targetColumn'), 'Y');
However if it is a short list then a nested if statement may be simpler to use.