This is the ValueSet that contains all the codes in Reason for ARV drug regimen substitution ValueSet (http://smart.who.int/hiv/ValueSet/HIV.D.DE418) and Reason for ARV drug regimen substitution ValueSet (http://smart.who.int/hiv/ValueSet/HIV.D.DE418). E.g. what you have to deal with if you get resources containing codes in either of them