Tip: What is (and isn’t) in your control regarding case-mix index

by Trey La Charité, MD, FACP, SFHM, CCDS

Editor’s Note: This article is an excerpt from The Physician Advisor’s Corner published in the Nov./Dec. edition of the CDI Journal. ACDIS members have access to this, and the entire edition of the Journal. Not an ACDIS member? No problem. ACDIS has plenty of articles, tips, tools, and other resources for FREE, just register your username and password. Non-members can click here to sign up.

Your CDI program successfully obtained consistent results over the last few years, and all is right within the CDI world. Then, the facility case-mix index (CMI) unexpectedly drops. Provided it rebounds, one or two months below its usual average is probably not cause for a great deal of concern. But what happens when the CMI shows an overall downward trend for six months, or a year, or two years? To be blunt, making an initial positive impact with your new CDI program is the easy part. Maintaining that momentum over the long haul, year after year, is a more difficult task.

Getting a handle on CMI fluctuations can be difficult. First, note that your facility’s CMI is not solely attributable to you, as the CDI physician advisor, nor is it solely attributable to your CDI program. Too many factors that directly affect your results are beyond your influence. You have no control over the patients that walk into your hospital on a daily or monthly basis, for example. Sometimes, this week’s patients simply aren’t as sick as last week’s (or last month’s) patients were. Sometimes, the physicians in your most profitable service line go on vacation.

Despite these facts, administrators generally attribute the facility’s CMI results solely to you and your CDI program. So when hospital management comes looking for answers, you need a comprehensive understanding of the variables at play.