Table 1. . Real-world progression-free survival outcome derivation in Optum's EHR and Flatiron Health.

PFS derivation	Optum's EHR	Flatiron Health
Progression date	Not available. Date of the subsequent line	Date of progression as derived from abstracted M spike or FLC
Definition	Time from index date to next treatment or death	Time from index date to either date of progression or death
Censoring	Last active date	Earliest date between last laboratory test date and end date of current LoT

EHR: Electronic health record; FLC: Free light chain; LoT: Line of therapy; PFS: Progression-free survival.