Z-codes as a social determinants of health screening tool for perioperative risk stratification in total hip arthroplasty

INTRODUCTION: Social determinants of health (SDOH) substantially influence surgical risk. However, International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) Z-code documentation as a perioperative screening tool for patients undergoing total hip arthroplasty (THA) has not been examined using electronic health record (EHR)-integrated data. This study aimed to analyze the association between documented SDOH-related Z-codes and postoperative complications following primary THA. 

METHODS: Using a national database, patients who underwent primary THA with minimum two-year follow-up were stratified by the presence or absence of SDOH-related Z-codes documented prior to the index procedure. Patients were propensity matched 1:1 to controls, adjusting for demographics and comorbidities. In total, 2,460 propensity-matched patients (1,230 per cohort) were analyzed. The primary outcomes were periprosthetic joint infection (PJI) and revision THA. Surgical outcomes were assessed at 90 days, one year, and two years. Risk ratios (RR) with 95% confidence intervals (CI) were calculated with P-values < 0.05 considered statistically significant. 

RESULTS: At 90 days, primary surgical outcomes did not differ significantly between cohorts. Patients who had SDOH demonstrated significantly higher rates of emergency department (ED) visits (RR 1.95, P < 0.001), readmission (RR 1.70, P < 0.001), and acute kidney injury (RR 1.63, P = 0.011). At one year, PJI rates were significantly higher in the SDOH cohort (3.90 versus 2.44%; RR 1.60, P = 0.038). At two years, PJI (4.55 versus 2.60%; RR 1.75, P = 0.009), revision THA (3.66 versus 2.20%; RR 1.67, P = 0.031), and periprosthetic fractures (2.60 versus 1.38%; RR 1.88, P = 0.030) were significantly elevated in the SDOH cohort. 

CONCLUSION: This study supports Z-code documentation as a clinically actionable perioperative screening tool for primary THA patients. The progressive emergence of surgical complications in patients who have SDOH Z-codes highlights the importance of sustained postoperative surveillance and dedicated perioperative interventions for this vulnerable population.