Table 1.

Results of the literature review.

Challenges	Description	Solutions
Electronic health records	Blockchain can provide an overarching framework that allows transparent and auditable access to disparate individuals’ health records stored off-chain. Patients would control data sharing parameters and access. Some solutions also discuss integrating health data from less traditional sources (eg, connected devices) and the creation of a health data marketplace, in which patients can sell their data to buyers through crypto tokens	MedRec [7,8,29], PatientTruth [30,31], CareX [32,33], MEDIS [34,35], GEM [36-40], MedicalChain [41,42], Humantiv and Medoplex [43-45]
Supply chain	Blockchain can establish an immutable record of a product’s tracing throughout the supply chain. In the case of health care, there have been many solutions that implement a blockchain to track-and-trace drugs and food products. In addition, smart contracts can be used as monitoring and alert systems for proper transport conditions (eg, a certain temperature range)	Drug supply chain: BlockVerify [46-48], Merck [49,50], Modum [51-54] Food supply chain: IBM Food Trust [55-58], Alibaba and Ant Financial [59,60]
Health insurance	Smart contracts on the blockchain can potentially help to settle health insurance claims and manage payment in real time, making the process more efficient and transparent for payers, providers, and patients. Other potential use cases include pharmaceutical and medical benefits, checks, and payment risk calculation	PokitDok and DokChain [61-67], GEM [39], Payspan [68,69]
Genomics	Much like with electronic health records, blockchain can provide a mechanism for controlling access to separate existing data banks of genetic information. In addition, blockchain can directly connect sellers of genomic data-to-data buyers, creating a genomic data marketplace. Data buyers could even provide rewards for individuals to sequence their genomes, creating their own data sets (eg, providing crypto tokens to individuals with a certain feature to be researched, in return for their genomic information)	Nebula Genomics [9,70], LunaDNA [71-75], Shivom [76-79], Zenome [80,81], EncrypGen [82-85], Macrogen [86-88]
Consent management	Blockchain can provide an immutable and timestamped log of consent, allowing individuals to grant and revoke consent for different data types and periods. In the case of health studies, it can also help researchers to easily track, manage, and update user consent	My31 app [89,90], Bitfury [91,92], HealthVerity Consent [93], Verifiable Audit Trail (tracking of events related to health data) [94-98], INSERMa and APHPb consent project [14], Queen’s University BlockTrial [99], Patient Control and Consent Blockchain initiative [100-102], Ubiquitous Health Technology Lab [6,103]

^aINSERM: Institut National de la Santé Et de la Recherche Médicale.

^bAPHP: Assistance Publique-Hôpitaux de Paris.