Background: Patients experiencing homelessness have unique healthcare needs due to barriers of care, lack of access to food and safety, and limited social services. Patients can be experiencing homelessness temporarily or chronically. They experience high rates of substance abuse, mental illness and other health problems like HIV. These unique circumstances make patients experiencing homeless unique from other patients and looking at their healthcare utilization patterns can help identify areas of unmet and greatest need for hospitals to be able to intervene. Prior to fiscal year (FY) 2022, all patients were grouped into one general ICD-10 code for homelessness. However, starting in FY 2022, the codes now can discern between unspecified homelessness (Z59.00), sheltered homelessness (Z59.01) and unsheltered homelessness (Z59.01).

Methods: The Vizient™ Clinical Data Base was queried for ICD-10-CM codes for homelessness (Z59.0 for FY 2019 and 2020; Z59.00-Z59.02 for FY 2022) for admissions during fiscal years 2020 to 2022.

Results: Prior to expansion of codes, inpatients experiencing homelessness were 72.4% male; after, homelessness unspecified and unsheltered homelessness patients are similar in proportion (72.5% and 73.9% male, respectively), but sheltered homelessness patients are less male (66.5%). Prior to FY 2022, homeless patients were approximately half (50.1%) non-Hispanic white; sheltered homeless patients were less likely to be non-Hispanic white (46.9%), and unsheltered homeless patients had a higher proportion of Hispanic patients than the other diagnosis groups (12.3% compared to 11.4% in sheltered group). The top diagnoses across all groups were mental health related. Both sheltered and unsheltered patients had approximately 5% fewer patients presenting for MS-DRG 885 -Psychoses, and approximately 2% fewer with MS-DRG 897 – alcohol, drug abuse or dependence without rehabilitation therapy without MCC. The length of stay increased for all homeless patients from 8.6 days to over 9.4 days for all groups, with unsheltered homeless patients having the longest LOS of 10.2 days. The average age of sheltered and unsheltered homeless patients was slightly higher than the unspecified group (48.1 and 48.3 years compared to 47.3 years). Patients in FY 2022 had higher overall proportion of patients with heart failure (MS-DRG 291 – 2.9-3.5% vs. 1.9% in FY 2019/20). Sheltered homeless patients had the lowest proportion of uninsured and higher proportions of patients on Medicare/Medicaid.

Conclusions: The expansion of homelessness ICD-10-CM codes allows for more insights into the healthcare utilization of both unsheltered and sheltered homeless patients. Sheltered homeless patients were less likely to be male, admitted for a mental health indication, more likely to have Medicaid and Medicare and more likely to be non-Hispanic black compared to unsheltered and unspecified homeless patients. By getting more insight into why homeless patients are seeking healthcare, providers can better identify resources that to support these patients.