Z-Code Health-Related Social Needs and Their Association with Post-Discharge Healthcare Utilization in Older Adults with Heart Failure and COPD

Background: Readmission rates are widely recognized indicators of healthcare quality, particularly for older adults. There is relatively little data on the role of health-related social needs (HRSNs) in post-discharge healthcare utilization (HCU). We investigated the association between HRSNs documented using Z-codes and unplanned 30- and 90-day HCU in older adults with heart failure (HF) and/or chronic obstructive pulmonary disease (COPD). Methods: This retrospective cohort study analyzed electronic health record (EHR) data from a regional health information exchange for individuals aged ≥ 65 with HF and/or COPD hospitalized at least once between 2019 and 2022. HRSNs were identified using ICD-10 Z-codes (Z55-Z65, Z75; Z61 for problems related to negative life events in childhood was excluded). The primary outcome, unplanned HCU, was defined as a composite of emergency department visits and unplanned inpatient admissions within 30- and 90-day post-discharge. Logistic regression models assessed associations between Z-code documentation and HCU, adjusting for demographic and clinical factors. Results: Among 19,536 older adults, 4.01% had Z-codes documented. The most frequently documented Z-code was “Medical Facilities/Other Health Care” (Z75) (31.1% of cases with Z-codes). Unplanned HCU occurred in 23.3% and 39.5% of individuals within 30 and 90 days, respectively. Z-code documentation was significantly associated with greater odds of HCU in univariable and multivariable models. After adjustment, individuals with Z-codes had a 17.7% greater odds of 30-day HCU (OR 1.18, 95% CI 1.00–1.38, p = 0.044) and 31.0% greater odds of 90-day HCU (OR 1.31, 95% CI 1.13–1.52, p < 0.001). Conclusions: HRSNs documented by Z-codes were associated with increased post-discharge HCU even after adjusting for demographic and clinical factors. The low documentation rate suggests that social needs may be underrecognized in EHRs, potentially limiting their use for identifying high-risk patients and informing post-discharge care. Future efforts should focus on improving Z-code utilization to enhance the integration of social risk factors into healthcare decision-making.