What is already known about this subject:
  1. A complete consensus has not yet been reached on the effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on the COVID-19 clinical course.
  2. Metformin and insulin are associated with better and poor COVID-19 clinical course, respectively.
  3. There are inconclusive results about calcium-channel blockers on COVID-19 clinical course.