CDIP DRG Optimization and Case Mix Index 4 — Questions and Answers
Question 1: A hospital's case mix index (CMI) dropped from 1.85 to 1.72 over one quarter despite stable patient volume. Which action is MOST likely to identify the root cause?
- Audit high-weight DRGs for documentation completeness and CC/MCC capture rates (Correct answer)
- Increase the number of elective surgical procedures scheduled
- Renegotiate payer contracts to improve reimbursement rates
- Expand the CDI team's focus to outpatient encounters
Correct answer: Audit high-weight DRGs for documentation completeness and CC/MCC capture rates
Auditing CC/MCC capture rates in high-weight DRGs directly identifies documentation gaps that reduce CMI.
Question 2: Which physician documentation practice most directly prevents DRG optimization in the inpatient setting?
- Using qualified diagnoses such as 'probable' or 'suspected'
- Documenting only the chief complaint without linking complications (Correct answer)
- Recording the discharge disposition in the discharge summary
- Specifying laterality for extremity conditions
Correct answer: Documenting only the chief complaint without linking complications
Failing to link complications to underlying conditions prevents coders from assigning CC/MCC codes that affect DRG weight.
Question 3: Under MS-DRG logic, a patient admitted for pneumonia with documentation of sepsis due to pneumonia would most likely be grouped to which category compared to pneumonia alone?
- The same base DRG since pneumonia is the principal diagnosis
- A higher-weighted DRG because sepsis functions as an MCC (Correct answer)
- A lower-weighted DRG due to increased complexity penalties
- An MDC 4 DRG regardless of the sepsis documentation
Correct answer: A higher-weighted DRG because sepsis functions as an MCC
Sepsis documented as a complication of pneumonia qualifies as an MCC, shifting the case to a higher-weighted MS-DRG.
Question 4: A CDI specialist queries a physician about a patient with a BMI of 42, hypertension, and type 2 diabetes who underwent CABG. What is the PRIMARY optimization opportunity?
- Documenting morbid obesity as a secondary diagnosis to capture the CC/MCC impact (Correct answer)
- Changing the principal diagnosis from CABG to hypertension
- Querying for a more specific cardiac catheterization procedure code
- Reclassifying the case from MDC 5 to MDC 3
Correct answer: Documenting morbid obesity as a secondary diagnosis to capture the CC/MCC impact
Morbid obesity (BMI ≥40) is an MCC that, when documented, can significantly increase the DRG weight for cardiac surgery cases.
Question 5: When comparing a hospital's CMI to peer institutions, which factor must be controlled to ensure a valid comparison?
- The number of CDI specialists employed per 100 beds
- Payer mix, teaching status, and service line distribution (Correct answer)
- The electronic health record vendor used by each facility
- Geographic location and local wage index values
Correct answer: Payer mix, teaching status, and service line distribution
Payer mix, teaching status, and service line distribution all directly influence CMI independently of documentation quality.
Question 6: A coder assigns acute respiratory failure as an MCC for a COPD exacerbation case. The physician's note states 'patient required supplemental oxygen; respiratory status improved.' What is the MOST appropriate next step?
- Accept the MCC assignment since supplemental oxygen implies respiratory failure
- Query the physician to clarify whether acute respiratory failure is clinically supported and should be documented (Correct answer)
- Remove the MCC and resequence COPD as the only diagnosis
- Assign hypoxia as a CC instead of acute respiratory failure
Correct answer: Query the physician to clarify whether acute respiratory failure is clinically supported and should be documented
Supplemental oxygen use alone does not clinically establish acute respiratory failure; a physician query is required to confirm or refute the diagnosis.
Question 7: Which metric best reflects the financial impact of a CDI program's DRG optimization efforts over time?
- Average length of stay per discharge
- Facility-adjusted expected CMI versus actual CMI trend (Correct answer)
- Total number of physician queries submitted per month
- Percentage of cases reviewed by CDI specialists
Correct answer: Facility-adjusted expected CMI versus actual CMI trend
Tracking actual CMI against facility-adjusted expected CMI isolates the documentation-driven component of case weight improvement.
CDIP DRG Optimization and Case Mix Index 4
A hospital's case mix index (CMI) dropped from 1.85 to 1.72 over one quarter despite stable patient volume.
Which action is MOST likely to identify the root cause?