The fact that NSAIDs increase the risk of developing hemorrhagic dengue (and death) is known for a long time; most people (especially from endemic areas) are well informed about the risks. For instance, in Brazil, TV ads from NSAIDs always end with a message stating that in case you suspect you have dengue fever to please refrain from using that particular type of medicine.
For this reason I don't think you will find any (recent) study with dengue fever patients stratified to NSAIDs intake.
We also do not use NSAID as our country is endemic for Dengue. It would be a great idea that running a TV add. We have also noted to that children who died with DHF (rare) have been given NSAIDs. Are there any animal studies at least?