PDPM PT & OT Case-Mix Categories, Functional Score & CMI

Under the new proposed PDPM final rule the functional score will be a key CMI driver. The functional score is determined using section GG and is recorded on the 5 day assessment. Section GG is fundamentally different than the ADL scores we are used to using from Section G. Some key differences:

  • Section GG instructs you to score what usually happens. Section G is all about what actually happened. Section G is typically filled out by CNAs, Section GG is not.
  • Traditionally we've only used the 4 late-loss ADLs. With PDPM we'll be using the admission performance scores for Section GG for everything except the wheelchair items.
  • Section GG scores are sometimes ambiguous. For example, partial/moderate assistance is where the helper does less than half of the effort. That's subjective nearly all the time.
  • Sections G and GG not only use different scoring units and scales, they have inverted acuity. A high functional rating means the patient is highly functioning. A high ADL score means the patient requires greater assistance to perform the ADL.

We're used to different case-mix weights depending on categories or groupings of RUGs. Within those categories we are used to see the CMI increase with ADL acuity. PDPM has clinical categories as well but t higher functional scores don't always mean higher CMI. See the chart below. (click to enlarge) 

Remember, the PT/OT pay bucket is generally greater as the patient has *more* function. The exception is when the the functional score is maxed out at 24. A functional score of 24 only has higher within tier CMI for the PT category "Major Joint Replacement or Spinal Surgery". This is different from RUGs IV where you are paid more when ADL scores are higher.

PT Clinical Categories, functional scores and case-mix (click to enlarge)

The categories are not evenly space in terms of functional scores either. The third tier in each category has functional scores from 10-23 which is wider than both tiers 1 and 2 combined. The 4th tier has only one functional score.

The story is the same for OT. See chart. (click to enlarge) At least the pattern is consistent here: the highest functional score is never the highest payer and 3 out of 4 times it's the lowest payer in that category.