In the rush to complete ICD-10 coding education, documentation improvement, and system updates, HIM managers may not have looked at looming MS-DRG shifts.
Various assessments by CMS, Milliman, and 3M found that the MS-DRG assigned to an ICD-10 claim did not always match the MS-DRG assigned to an ICD-9-CM source claim. The change in DRGs in ICD-10 compared to ICD-9-CM is referred to as MS-DRG shift, says Gloryanne Bryant, RHIA, RHIT, CCS, CDIP, CCDS, an AHIMA-approved ICD-10-CM/PCS trainer with more than 30 years of experience in HIM.
The CMS and 3M studies have determined that overall, approximately 1% of MS-DRGs will shift under ICD-10. "To most of us that seems very, very small," Bryant says.
However, facilities need to break down which MS-DRGs are shifting. "If those shifts are in more common MS-DRGs that we see in our patient population, the impact could be greater," Bryant says.
Of the 1.07% of MS-DRGs that will shift, 41% will shift to a higher-paying MS-DRG, while 66% will move to a lower-paying MS-DRG, according to a CMS study.
CMS has indicated that the MS-DRG payment calculation under ICD-10 is a replication of the ICD-9-CM system, Bryant says. Although CMS has indicated that this change is budget neutral, there will be some payment redistribution based on the differences between ICD-9-CM and ICD-10.
Don't forget to share information about MS-DRG shifts with chief financial officers and comptrollers as well, Bryant says.
MS-DRG shift
ICD-10-CM and ICD-10-PCS codes provide better clinical specificity as well as refinement to financial/reimbursement models, Bryant says.
"The ICD-10 code sets are not just a simple update of ICD-9-CM code sets used currently for reporting patient encounter information, but have changes in structure as well as changes in concepts that make them very different," Bryant says. "Every organization needs to make sure that payments based on ICD-10 must be within an understandable and acceptable variance from that of ICD-9 payments."
Start by identifying your top 25 medical MS-DRGs and your top 25 surgical MS-DRGs, Bryant says. If you don't have time to run that many reports, at least look at your top 10 in each category.
Check how often you report specific MS-DRGs, principal diagnoses, and secondary diagnoses to make sure they are consistent before and after implementation. If the frequency changes, you need to determine the cause.
MS-DRGs will shift for several reasons, says Lori P. Jayne, RHIA, HIM director for Lahey Health System in Burlington, Massachusetts.
Are cases being coded correctly? Is the documentation adequate to capture new/different codes? Did the coding guidelines change?
Four factors affect MS-DRG—based reimbursement between ICD-9-CM and ICD-10:
- Number of discharges for each MS-DRG
- Percentage of time the MS-DRG shifts
- Change in weight for each shift between ICD-9-CM and ICD-10
- Base rate for the relevant payers
"These four factors are vital to more efficiently calculating reimbursement impact under ICD-10," says Bryant.
Anemia and malignancy
One reason MS-DRGs will shift is because some coding guidelines are changing. For example, a patient with Burkitt lymphoma is admitted for treatment of anemia due to chemotherapy and only the anemia is treated.
The ICD-9-CM Official Guidelines for Coding and Reporting instruct coders to report the anemia code as the principal diagnosis followed by the code for the malignancy.
When the admission is for management of an anemia associated with chemotherapy or radiotherapy and the only treatment is for the anemia, report the anemia as the principal diagnosis followed by the appropriate code(s) for the malignancy.
Anemia due to antineoplastic chemotherapy is reported with ICD-9-CM code 285.22 (anemia in neoplastic disease), which maps to MS-DRG 812 (red blood cell disorder without MCC) with a relative weight of 0.7957. The secondary diagnosis is 200.20, a CC.
However, the ICD-10-CM Official Guidelines for Coding and Reporting instruct coders to report the malignancy as the principal or first-listed diagnosis followed by the appropriate code for the anemia (such as code D63.0, anemia in neoplastic disease).
The principal diagnosis for the patient with Burkitt lymphoma becomes C83.70 with a secondary diagnosis of D63.0. The anemia is not classified as either a CC or MCC in ICD-10-CM. This case maps to MS-DRG 842 (lymphoma and non-acute leukemia without CC/MCC), which has a higher relative weight of 1.0389.
Run a report of all of your cases from the past year that map to MS-DRG 812. Then look for any secondary diagnoses of a malignancy, Bryant says. Recode the record with the malignancy as the principle diagnosis and see which MS-DRG it maps to in ICD-10.
The majority of cases will shift to the body system, so you will see a variety of new MS-DRGs, Bryant says. In many cases, those new MS-DRGs will have a higher weight than the anemia MS-DRG.
"You will see some changes taking place," Bryant says. "In order to know how much, you'll have to run a report on the anemia MS-DRG and then study or analyze the results."
Decreased specificity
Another reason for MS-DRG shift results from a decrease in specificity. In some cases, ICD-10-CM does not have a code to match an ICD-9-CM code, Jayne says. For example, ICD-9-CM has a code for esophageal hemorrhage—530.82. ICD-10-CM does not.
"The esophagus doesn't just bleed," Jayne says. "The bleeding is caused by something. If you can get the physician to link the bleeding and the cause in the documentation, you can keep the specificity."
ICD-9-CM code 530.89 (other disorders of esophagus) groups to MS-DRG 391 with the addition of an MCC. Code 530.89, which is not an MCC, is the closest match to ICD-10-CM code K22.8 (other diseases of esophagus), which includes esophageal hemorrhage in its definition and is the cause of about 90% of the weight change. A record without an MCC will shift to a lower-weighted MS-DRG.
Rib fractures are another example. In ICD-9-CM, coders report each fracture separately using ICD-9-CM code 807.0x (closed rib fractures) and 807.1x (open rib fractures). Each code requires a fifth digit to identify the number of ribs fractured. For example, if a patient suffered closed fractures to three ribs, coders would report 807.03.
ICD-10-CM classifies the number of rib fractures as one rib (S22.3-) or multiple ribs (S22.4-). Coders will use the same code to report fractures of two ribs or eight ribs. That will change the MS-DRG, Jayne says.
Hypertension
ICD-10-CM consolidates the three codes currently used for hypertension into one code (I10). Shifts occur for different reasons, mostly having to do with the loss of the CC. One reason accounts for 67% of the shift and 80% of the aggregate weight reduction: malignant hypertension, Bryant says.
In ICD-9-CM, malignant or accelerated hypertension (401.0) served as a CC. However, hypertension is no longer a CC in ICD-10-CM.
In ICD-9-CM, codes 401.0 and a related code (402.00, malignant hypertensive heart disease without heart failure) are on the list of CCs.
ICD-10-CM does not classify the concept of malignant hypertension as a distinct clinical condition, so there are no comparable ICD-10-CM codes specifying malignant hypertension on the CC list in ICD-10-CM MS-DRGs, Bryant says.
If hypertension provided the only CC on a case, you will likely see a shift in the MS-DRG to a lower-paying one, Bryant says.
Run a report to identify cases with 401.0 as a secondary diagnosis. Determine how often hypertension is the only CC. Recalculate the impact to determine impact of the lower-paying MS-DRG, Bryant says.
Often patients with accelerated or malignant hypertension may suffer kidney failure as a result of the hypertension. Coding professionals and even CDI staff need to look for other clinical indicators and conditions that could be CCs or MCCs, Bryant says. For example, a patient with hypertension may also suffer from acute kidney failure (ICD-10-CM code N17.9), which is a CC.
"With those shifts we want to bring attention to identifying whether the patient has any renal failure going on," Bryant says. Coding professionals may need to dig deeper into the record to find that information.
"That may result in us being able to code N17.9 code instead of the 401.0 code because we've captured that opportunity," Bryant says.
Also look at cases that map to MS-DRG 292 (heart failure and shock with CC). Data shows that malignant hypertension is frequently the secondary diagnosis in cases that map to MS-DRG 292, Bryant says.
Coding professionals and CDI specialists should again look for additional CC or MCC opportunities that may have been missed.
Editor’s note: This article was originally published in the September issue of Briefings on Coding Compliance Strategies. Email your questions to editor Steven Andrews at sandrews@hcpro.com.