Case mix index (CMI) is the metric by which the relative cost of treating residents covered by Medicaid is measured.  It also sheds light on the type of residents being treated and the burden of care required.  Because the primary payer source for most facilities is Medicaid, it is important that providers monitor CMI accuracy closely. In order to capture the complexity of services provided, providers should evaluate system processes, coding compliance and consider continual quality improvement measures to address potential errors and missed opportunities.

Some of the greatest opportunities found in audits relate to inadequate supporting documentation. Documentation must accurately reflect the resident conditions and services provided.  Insufficient documentation may lead to a recoupment or reduction of payment. Inaccurate charting can result in under coding, which lowers CMI with direct implications to the bottom line. Some common examples of opportunities or process improvement factors are listed below—note: examples vary dependent upon the state grouper.

Shortness of Breath Lying Flat

Shortness of breath while lying flat is a common symptom for a resident that has COPD. However, if not properly documented, this variable may be missed.  Consider including assessment of shortness of breath lying flat as part of an order template or adding as a checkbox on facility nursing assessments.  Ask the resident during the reference period “if the bed is completely flat and there is no pillow, does shortness of breath occur?” then document the response.

Respiratory Therapy

When respiratory therapy is provided, it is important that trained respiratory nurses or respiratory therapists document the duration of treatment in minutes. Keep in mind that a day of therapy is defined as treatment for 15 minutes or more.  Only minutes that the respiratory therapist or respiratory nurse spends with the resident are recorded on the MDS. This time includes resident evaluation/assessment, treatment administration and monitoring, and setup and removal of treatment equipment.  To improve documentation accuracy, consider adding an order template that includes respiratory assessment and monitoring before and after the service (i.e. lung sounds, pulse, respirations, oxygen saturation, number of minutes.)

Parental/IV Feeding

Parental/IV feeding can be coded in K0510A1 or 2 if received in the last 7 days either at the nursing home, at the hospital as an outpatient or an inpatient, when there is supporting documentation that reflects the need for additional fluid intake specifically addressing a nutrition or hydration need. MDS Coordinators should review hospital MARs prior to establishing the ARD.  If the acute care paperwork was not sent, the facility should request from the provider.  In many cases, facility staff are allowed remote access to the hospital EHR so that the facility can retrieve supporting documentation on their own.  A new order for IV fluids for a facility resident should be communicated promptly to the MDS Coordinator.

Pressure Ulcers/Injuries and Skin Conditions

A thorough assessment process should be applied to the early detection and identification of skin/wound issues. Understanding wound characteristics, appropriate staging, and seeking clarification when needed will assist in the determination of wound etiology and result in more appropriate resident care interventions and accurate MDS coding.

Restorative Nursing Programs (RNP)

Many facilities have opportunities to develop or improve restorative programming. For those residents that fall in the reduced physical function or cognitive/behavior nursing categories, the RNP is part of the end-split that increases the CMI. Facility leaders should consider how a comprehensive restorative nursing program can help to maintain or improve resident function,   improve quality outcomes, ensure regulatory compliance, impact CMI and reduce costs associated with resident decline.


Residents who qualify for one of the higher groups of Clinically Complex, Special Care Low, or Special Care High will receive a higher CMI if indicators of depression are present as identified through the PHQ-9 assessment and total score.  Ensure the staff member responsible for completing the PHQ-9 interview is knowledgeable in how to properly deliver the assessment.


Accurate diagnosis coding can ensure accurate reimbursement. ICD.10 coding should meet RAI Manual guidelines and ICD-10-CM Official Guidelines for Coding and Reporting along with the appropriate supporting documentation in the medical record.  Examples of diagnoses that may significantly impact CMI include Coma, Multiple Sclerosis, Cerebral Palsy, Hemiparesis, Quadriplegia, Septicemia, Pneumonia, Parkinson’s, COPD with shortness of breath while lying flat, Dehydration, Internal Bleeding, and Hematuria.  If a diagnosis/problem list is used, code only diagnoses confirmed by the physician and confirmed as active.  Query the physician for clarification as needed, and request additional documentation prior to the ARD when there is conflicting, incomplete or vague information in the medical record.


Fever alone or fever with pneumonia, tube feeding or vomiting can increase CMI if recorded as 100.4 or greater upon admission or when a resident’s temperature is 2.4 degrees above baseline.  It is beneficial to establish a baseline temperature soon after admission/re-admission and then annually.  Also, review vital sign alerts/reports daily in clinical meeting to facilitate awareness of increased temperature.


Understanding how therapy impacts CMI is crucial.  It is important to have effective communication between the MDS Coordinator and Rehab Manager.  There should be a communication process to notify the MDS Coordinator when therapy treatment is ordered such as with Medicare Meeting.  Also, the ARD should be established as soon as a combination of 5 days and 150 minutes or 45 minutes and combination of 3 days of therapy with at least 2 restorative nursing programs at least six days for 15 minutes is achieved.  The rehab RUG begins the date of the ARD in most states unless therapy begins with admission.

This is not an exhaustive list of opportunities. Providers should monitor other areas such as ARD management, clinical services and conditions provided, and clinical changes among other qualifiers.  Keep in mind that documentation for long-term care residents is not usually performed on a daily basis in the long-term care setting. Therefore, it is important to emphasize that acute condition changes should be documented as they occur and communicated to the clinical team.  Developing appropriate policy and procedures, understanding the different RUG qualifiers, and communicating changes amongst the interdisciplinary team members will assist your team in ensuring accurate case mix.


Contact Proactive to learn more about our budget friendly CMI audit services, documentation training, and MDS coding support solutions.


Center for Medicare and Medicaid Services. (2019). MDS 3.0 RAI Manual. Retrieved from:

Center for Medicare and Medicaid Services. State Operations Manual. Transmittal. Rev. 11-22-17.



Blog by Kristen Walden, MSN, RN, RAC-CT, Proactive Medical Review




Blog by Jessica Cairns, RN, RAC-CT, CMAC, Proactive Medical Review


Learn more about Shelly and the rest of the Proactive team.