OBJECTIVES: Mortality is an important outcome in pharmacoepidemiological research but is often missing or incomplete in real-world evidence (RWE) sources. This study evaluates mortality capture across administrative claims and government databases, aiming to evaluate death reporting and provide options for enhancing mortality capture in RWE.

METHODS: Patients diagnosed with septicemia (where deaths are more likely to occur in hospitals) or metastatic lung cancer (mLC) (where deaths can occur in or outside hospitals) from 2018 to 2020 were selected from the MarketScan® Commercial and Medicare Database (MSN) by Merative^TM and linked to the Social Security Administration’s Death Master File (DMF). Inpatient discharge deaths in MSN and all deaths in DMF from 2018 to 2022 were identified. The study analyzed consistency and differences in reported deaths and assessed end-of-life care and disenrollment status within +/- 6 months of death.

RESULTS: Among patients with septicemia (N = 105,812), 19,943 deaths (18.8%) were identified (72.1% in MSN, 38.9% in DMF). Conversely, for patients with mLC (N = 13,558), 2,857 (21.1%) deaths were identified (51.4% in MSN, 56.1% in DMF). In both conditions, a significant portion of deaths were exclusively recorded in one database (septicemia: 11.0% in both MSN and DMF, 27.9% in DMF only, and 61.1% in MSN only; mLC: 7.5% in both MSN and DMF, 48.6% in DMF only, and 43.9% in MSN only). Over 95% of patients whose death was recorded in MSN had >=1 end-of-life care event and >80% disenrolled from the database within 6 months of death.

CONCLUSIONS: Administrative claims data with the capability to capture continuous enrollment status and government databases are complementary for capturing mortality data. Administrative data can be used to identify deaths in the inpatient setting, while DMF can augment this by identifying deaths outside of inpatient settings. Utilizing both sources is essential to improve death ascertainment in RWE research.