  Self-Sovereign Identity (SSI), a Blockchain-based technology for digital
identity management, is a promising concept for handling health data. It could
represent a step forward in empowering users, granting them control over their
data. This work conducts a systematic literature review to investigate
state-of-the-art measures based on SSI and Blockchain technologies for dealing
with electronic health records (EHRs), identifying gaps, and determining the
key questions for future research. As a result, this review shows a growing
interest in Blockchain methods to handle EHRs, but few works consider using the
self-sovereign identity approaches. The results obtained in this work also
suggest that: Blockchain technologies provide a viable alternative to deliver
EHR solutions such as patient monitoring, healthcare data trading, and
prescription control; consolidated Blockchain technologies are the preferred
core components of most effective strategies; keeping raw health data off-chain
helps to create scalable solutions; health data standards make searching
medical records in Blockchain structures feasible; Smart Contracts are
essential components of Blockchain-based EHR solutions; the concepts of data
ownership and Self-Sovereign Identity have been neither adequately defined nor
employed in the health context.
