I need to find a Level 1 and Level 2 of evidence for my PICOT question.

I need to find a Level 1 and Level 2 of evidence for my PICOT question. "In older adult diagnosed with heart failure, how effective are follow up phone calls compared to no follow up to prevent readmission within 30 days of discharge. I need help with categorizing which article is 1 or 2.

https://www.ncbi.nlm.nih.gov/pubmed/26978568

This article is a case control study. Does that mean this is Level 2?