Association of social determinants of health diagnosis codes with overall survival in Medicare-insured patients with cancer.

[BACKGROUND] Social determinants of health (SDOH) impact long-term cancer outcomes. Since 2015, the Centers for Medicare & Medicaid Services recommends using International Classification of Diseases diagnosis codes Z55-Z65 to document specific SDOH. We examined the association of these Z-codes with survival in patients with cancer.

[METHODS] Patients with breast, colorectal, lung, prostate, or pancreatic cancer were identified in the SEER-Medicare database (2016 to 2019). The primary exposure was a Z-code claim in the 12 months before or 6 months after cancer diagnosis. The primary outcome was overall survival. Multivariable Cox regression was performed to examine the association of Z-code claims with overall survival, controlling for demographic and clinical covariates.

[RESULTS] Of 210,093 patients, 4,351 (2.1%) had at least one Z-code claim. The most frequent codes were for problems with social environment (Z60 47.3%) or a primary support group (Z63: 27.2%). Codes were submitted most often by home health agencies (57.8%) and least often by inpatient facilities (1.7%). In adjusted analyses, any Z-code claim was associated with worse survival than was no claim (hazard ratio, 1.09 [95% CI, 1.05-1.14]; p < 0.01), although the associations varied by Z-code.

[CONCLUSIONS] SDOH Z-codes are rarely submitted with billing claims for Medicare patients with cancer. Whether Z-codes reflect the social needs of patients with cancer remains unclear. With current coding, any SDOH Z-code is associated with poor survival in these patients, but individual Z-codes are not consistently associated with survival. Further studies should determine whether SDOH Z-codes enable effective risk adjustment in a value-based healthcare system.