The public comment period ends June 24, 2019 on the CMS proposed changes to CCs and MCCs.

The Centers for Medicare & Medicaid Services (CMS) Inpatient Prospective Payment System (IPPS) proposed changes for acute-care hospitals in the 2020 fiscal year were announced on April 23 and released through the Federal Register on May 3 (the link appears below). Contained within the 520 pages is a discussion of the complication or comorbidity (CC) and major complication or comorbidity (MCC) changes and the associated tables (Excel files) listing the changes.

Per the IPPS proposed rule in the Federal Register, CMS notes that “in our examination of the claims data, we apply the following criteria established in FY 2008 (72 FR 47169) to determine if the creation of a new complication or comorbidity (CC) or major complication or comorbidity (MCC) subgroup within a base MS–DRG is warranted:

  • A reduction in variance of costs of at least 3 percent;
  • At least 5 percent of the patients in the MS-DRG fall within the CC or MCC subgroup;
  • At least 500 cases are in the CC or MCC subgroup;
  • There is at least a 20 percent difference in average costs between subgroups; and
  • There is a $2,000 difference in average costs between subgroups.

In order to warrant creation of a CC or MCC subgroup within a base MS-DRG, the subgroup must meet all five of the above criteria. Some of the key tables to review by health information management (HIM), clinical documentation improvement (CDI), and revenue cycle are the following:

FY 2020 Table 6I.1.—Proposed Additions to the MCC List
FY 2020 Table 6I.2.—Proposed Deletions to the MCC List
FY 2020 Table 6J.1.—Proposed Additions to the CC List
FY 2020 Table 6J.2.—Proposed Deletions to the CC List

For each secondary diagnosis, CMS measured the impact in resource use for the following three subsets of patients:

  1. Patients with no other secondary diagnosis or with all other secondary diagnoses that are non-CCs.
  2. Patients with at least one other secondary diagnosis that is a CC, but none that is an MCC.
  3. Patients with at least one other secondary diagnosis that is an MCC.

Following the above process, CMS then assigned a numeric resource impact value to each diagnosis code. Review page 19235 of the IPPS proposed rule for more details on the analysis that CMS conducted.


So, the first area one would want to look at is the deletions from the CC/MCC lists. There is recommended removal of some pressure ulcer codes from the MCC list, along with a suggestion to move them to CCs. Here is a portion of the ICD-10-CM table regarding pressure ulcers:


For the 153 MCCs on this proposed deletion list, here’s a portion of the ICD-10-CM codes for “initial encounter for closed fracture … proposed to be removed (deleted):”


Then review the table for proposed additions to the MCC list. Do likewise for the CCs.


Per the Federal Register, “as a result of these proposed changes, of the 71,932 diagnosis codes included in the analysis, the net result would be a decrease of 145 (3,244 to 3,099) codes designated as an MCC, a decrease of 837 (14,528 to 13,691) codes designated as a CC, and an increase of 982 (55,142 to 54,160) codes designated as a non-CC.

This comparison chart can be located on page 19236 of the Federal Register version, as well as other information regarding the proposed changes to the CC/MCC list.


There is also a proposal that neoplasm codes and several acute myocardial infarction codes no longer be used as a secondary diagnosis (removing them as MCCs and making them CCs).

 It would be very helpful for your facility or organization to run some diagnosis frequency data reports on several of these specific CC/MCC (ICD-10-CM codes) that are being removed to see what the impact to your inpatient case mix could be. The impact may be less than anticipated due to having multiple CC/MCCs on a given encounter, but this is worth a look.

CMS is asking for public comments on each of the MS-DRG classification proposed changes, as well as the other proposals to maintain certain existing MS-DRG classifications discussed in this proposed rule. When submitting comments, refer to file code CMS-1716-P. CMS will accept comments in the following manner:

  1. Electronically. You may submit electronic comments on this regulation to Follow the instructions under the “submit a comment” tab.
  1. By regular mail. You may mail written comments to the following address only: Centers for Medicare & Medicaid Services, Department of Health and Human Services, Attention: CMS-1716-P, P.O. Box 8013, Baltimore, MD 21244-1850.

Please allow enough time for mailed comments to be received before the close of the comment period.

  1. By express or overnight mail. You may send written comments via express or overnight mail to the following address only: Centers for Medicare & Medicaid Services, Department of Health and Human Services, Attention: CMS-1716-P, Mail Stop C4-26-05, 7500 Security Boulevard, Baltimore, MD 21244-1850.


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