Blockchain applications in health care for COVID-19 and beyond: a systematic review

Abstract

The COVID-19 pandemic has had a substantial and global impact on health care, and has greatly accelerated the adoption of digital technology. One of these emerging digital technologies, blockchain, has unique characteristics (eg, immutability, decentralisation, and transparency) that can be useful in multiple domains (eg, management of electronic medical records and access rights, and mobile health). We conducted a systematic review of COVID-19-related and non-COVID-19-related applications of blockchain in health care. We identified relevant reports published in MEDLINE, SpringerLink, Institute of Electrical and Electronics Engineers Xplore, ScienceDirect, arXiv, and Google Scholar up to July 29, 2021. Articles that included both clinical and technical designs, with or without prototype development, were included. A total of 85 375 articles were evaluated, with 415 full length reports (37 related to COVID-19 and 378 not related to COVID-19) eventually included in the final analysis. The main COVID-19-related applications reported were pandemic control and surveillance, immunity or vaccine passport monitoring, and contact tracing. The top three non-COVID-19-related applications were management of electronic medical records, internet of things (eg, remote monitoring or mobile health), and supply chain monitoring. Most reports detailed technical performance of the blockchain prototype platforms (277 [66·7%] of 415), whereas nine (2·2%) studies showed real-world clinical application and adoption. The remaining studies (129 [31·1%] of 415) were themselves of a technical design only. The most common platforms used were Ethereum and Hyperledger. Blockchain technology has numerous potential COVID-19-related and non-COVID-19-related applications in health care. However, much of the current research remains at the technical stage, with few providing actual clinical applications, highlighting the need to translate foundational blockchain technology into clinical use.

Figure 1

Blockchain-based health-care data management system between multiple stakeholders (nodes) within a health-care ecosystem Hybrid and private blockchains are maintained by permissioned parties (eg, hospitals and government agencies). Confidential health-care data are saved on-premise and governed by reputable hospitals, laboratories, or similar institutions. High-volume health-care data (eg, radiology image and genomic data) are stored in off-chain data storage (ie, not on the blockchain ledger) for cost savings. Options of on-chain data management can include the logging of Merkle tree roots or designating edge devices as light nodes with storage of a hash function for data integrity verification. Health-care data ownership is returned to patients, who can authorise data use to clinics, research institutes, and insurers during specified time periods. Data access rights and trading transitions are saved and tracked on transparent, immutable, and traceable-distributed ledgers based on a majority agreement consensus protocol. Blockchain-based tokenisation cultivates trustworthy health-care data marketplace and collaboration ecosystem. DNN=deep neural network.

Figure 2

Preferred Reporting Items for Systematic Reviews and Meta-analyses flow diagram of the article selection process Of a total of 85 375 initial articles, 415 were eligible for data abstraction. The most common sources for the selected articles were IEEE Xplore followed by PubMed. IEEE=Institute of Electrical and Electronics Engineers.

Figure 3

Distribution of studies based on clinical translation, technical demonstration, and technical design Studies without demonstration of technical results were classified as technical designs. Most studies underwent technical demonstration and reported simulation results including block file sizes, latency, throughput rates, and horizontal scalability.

Figure 4

Trends in non-COVID-19 blockchain research over the past 4 years for the three most common clinical applications The top three most common applications are supply chain monitoring; mobile health, remote clinical and research monitoring, and internet of things for eHealth; and electronic medical records monitoring, storage, sharing, and access control. MH=mobile health. RM=remote monitoring. IoT=internet of things. *Up to July 29, 2021.