In the FY 2027 Inpatient Prospective Payment System (IPPS) Proposed Rule, the Centers for Medicare and Medicaid Services (CMS) has introduced a notable and potentially controversial change: the removal of homelessness and related housing instability ICD-10-CM Z codes (Z59 series) from the Complication or Comorbidity (CC) list.
If finalized, this policy would reclassify these codes from CC back to non-CCs, effectively eliminating their impact on MS-DRG assignment and reimbursement. This proposal is described in the proposed ruling as a broader recalibration by CMS one that re-centers the inpatient prospective payment system (IPPS) on clinical severity rather than social complexity.
Historically, CMS has used CC and MCC designations to capture the relative resource utilization associated with secondary diagnoses. In reviewing the Z59 codes. CMS acknowledged that internal data analysis showed values approaching a CC-level resource impact.
However, the agency ultimately concluded that these codes represent social circumstances rather than medical conditions and therefore should not drive severity classification.
CMS described a parallel in the ruling to its FY 2008 IPPS reforms, when chronic conditions without acute exacerbation were removed from the CC list. The underlying rationale used was that CC/MCC designation should reflect the expected resource consumption required to treat an underlying medical condition, not the presence of social risk factors alone.
Operational and Financial Implications
For hospitals, this change is far from symbolic. The Z59 codes, particularly homelessness, have increasingly been leveraged to capture the complexity of discharge planning, prolonged length of stay, and increased care coordination efforts to manage patients’ medical conditions. The removal as CCs will have several downstream effects such as a decrease in reimbursement, an impact to CMI, and a loss of coded recognition for social complexity.
While CMS acknowledges that patients experiencing homelessness require increased resources, it stops short of allowing that complexity to influence payment. Instead, the agency emphasizes that resource use should be captured through documentation of acute medical conditions.
Frankly, this creates a practical tension. Hospitals are still expected to manage the very real throughput, discharge, and care coordination barriers associated with homelessness and housing insecurity, but now this will be without the corresponding reimbursement recognition.
Not unlike the prior trends we have seen with this current administration, CMS is continuing to draw a clear boundary between medical care and social determinants of health.
The comment period is open now through June 9, 2026.
