Highest MS-DRG Weight versus Highest SOI/ROM

Taking an informal poll on which Principal Diagnosis (PDx) to sequence first in the following scenario.  There are two conditions that equally meet the definition of PDx.  One has a higher MS-DRG/CMI.  The other has a higher SOI/ROM.  Which would you sequence first and why?

We traditionally have always gone with highest MS-DRG weight but with recent conversations over the last several years, specifically in regards to mortality index, we are curious what others are doing. 

 Thank you! 


  • Our software does not calculate SOI/ROM, so we are blind to that, but we have come across certain cases where the Relative weight is higher, but the calculated dollar amount is lower.  We will code to the higher weighted DRG rather than the dollar amount to help influence our CMI.

    A hospital's CMI represents the average diagnosis-related group (DRG) relative weight for that hospital. It is calculated by summing the DRG weights for all Medicare discharges and dividing by the number of discharges

  • Complex question:  Some payers use the SOI for payment rather than the MS-DRG.  That should be considered. 

      If your facility has a strategy to support the O/E ratio via ROM scores,  your site may wish to 'sacrifice' the higher MS-DRG for the APR-DRG having the higher ROM.    This type of complex decision is often made in conjunction with HIM, CDI, and Quality.  "Some" HIM departments have a policy that they will use and support the higher ROM in this situation IF the decrease in $$ is no less than - complete the blank.    This is not unethical as long as there are compliant choices for competing principal diagnoses.  An encoder loaded with the proper financial tables will report the actual dollar amounts for MS-DRG scenarios and the MS-DRGs, being governed by the Feds, have consistent relative weights no matter the state.

     The payment rates for SOI have a different, and more complex formula and the financial tables vary state to state.

    Paul Evans


  • This is an issue of organizational goals and really can only be made with the involvement of leadership (including finance). If a facility has a specific quality metric(s) that they are  struggling with, it may be in their interest to consider sequencing that does not maximize RW in specific scenarios (assuming there are clearly co-equal diagnoses). For example, if you are struggling with PNA readmissions a facility may choose to carefully evaluate these cases for alternate options.  Prior to deciding to do this, it is important that there is clear understanding of what data drives the specific measures of concern to ensure that you are actually impacting the desired measure.


  • And when all of the above fails simply do this: 

    Sequence the record in accordance with the best possible reconciliation of the clinical truth with reporting guidelines.  IE...what is the diagnosis MOST responsible for occasioning when you consider the evaluation, severity and treatment during that first 48 hours surrounding the circumstances of the initial  admission?

    If you are ignoring the above compliance issue in favor of gaming a particular metric such as CMI or ROM, you COULD be creating not only confusion and resentment from your coding staff but also setting yourself up for some very hard questions if you are ever audited.

    Now having said all that....if all things really are equal, I believe CMS seems to want us to prioritize quality concerns (ROM, HCC, PSI, VBP, etc.) ahead of a straight interpretation of the MS-DRGs, at least if you believe all of the hype the last five years about a quality focused value based health care system which will incentive good care over care volume.

    Not everyone has drank the kool aid yet though. 
  • YES! Agree with Allen. 

  • I am more with Katy on this one. You should ask your leadership for guidance, understand the needs of your organization and prioritize accordingly, just make sure you follow the coding guidelines.

    Also when two or more diagnoses are present on admission, traditionally the condition that requires more resources for treatment is selected as a principal diagnosis, though this can also vary in certain situations.

  • Thank you all for your input!  I agree it is a complex one, always needs to put compliance first, and should involve leadership input for organizational goals if two diagnoses happen to be equal. 

    Thank you again for your time. 

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