Do you have a link to the article you were reading or did you pull the facts and make the connections yourself?
The data takes some digging. The source is the Wall Street Journal article, but you have to be subscribed to read it. I will also link to another article that talks about the WSJ article.
WSJ - In Medical Triumph, Homicides Fall Despite Soaring Gun Violence
Chicago Mag - Trauma Care and Death as the Ultimate Data Point