Student or Learner
Is there anything wrong in using healthcare-related as an adjective here:
These healthcare-related deaths were NOT deaths caused by incurable life-threatening illnesses, but illnesses that could have been treated if the patient were wealthy enough.
I'd put a comma after "incurable."
"Were" might be better as "had been."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.