Table 2. Causes of loss to follow-up during the study period, Aragon, Spain, January–May 2021.

Causes	No. patients
Expiration of service*	3,328
Death	2,903
Change of residence to another region of Spain	2,020
Loss of entitlement†	250
Change of residence to another country	15
Duplicate user‡	2
Unknown	3,039

*Aragon Health Service healthcare ended for administrative reasons. Most common were expiration of temporary service for persons who moved from another self-governing region of Spain for a specific period of time (maximum 6 months), subject to renewal; and for foreign citizens with no residence license who had not applied for renewal of Aragon Health Service–provided healthcare in 2 years. †Loss of entitlement to Aragon Health Service–provided healthcare when person begins working unless they renounce mutual insurance company–provided healthcare (applies to a few public workers in Spain whose healthcare provider is a mutual insurance company). ‡Health record of participant was duplicated in the Aragon Healthcare System Users Registry.