ACE and AIDS: aat least one of the listed diseases: chronic kidney failure, metastatic cancer, hematological malignancies, AIDS and other causes of immunosuppression, severe hepatic failure, NYHA class IV and pre-existing chronic severe hypoxia; bat least one of the listed drugs: angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, calcium antagonists, minoxidil, moxonidine, nitrates, and molsidomine; cFisher’s exact test; Two Sample t-test; Wilcoxon rank sum test