Hospitals infrequently document social risk factors using Z codes, particularly for clinically complex patients, according to research from the University of Pennsylvania’s Leonard Davis Institute of Health Economics.
Researchers examined inpatient claims for more than 7 million Medicare beneficiaries hospitalized in 2022, 86% of whom were over age 65. Just 2% of patients had at least one Z code — a set of billing codes used to flag social risks such as food insecurity or housing instability that could influence health. Hospitals are not required to collect Z codes for reimbursement
Three more study findings:
- Z codes were documented for 1.5% of high-complexity patients, compared to 2.8% of low-complexity patients.
- Patients with the highest 30-day mortality risk were least likely to have Z codes documented.
- Patients with Z codes in their records had a nearly 1% lower risk of death after discharge.
The study authors warned that limited and uneven Z code documentation may misrepresent the true scope of patients’ social risk. By undercoding the sickest and most vulnerable patients, hospitals may unintentionally distort data used to guide funding, quality improvement and value-based payment models — potentially leaving high-need populations underserved, they said in an Oct. 16 news release.
