The potential for the use of blockchain technology in hospitals has started to be tested in several pilot projects globally. Last year in the United States, Booz Allen Hamilton Consulting developed and implemented a blockchain-based pilot platform designed to help the Food and Drug Administration's Office of Translational Sciences explore how to use the technology for healthcare data management (Figure 1). The pilot project is currently being implemented at four major hospitals; it is using Ethereum to manage data access via virtual private networks. The project is built on the IPFS to utilize encryption and reduce data duplication via off-chain cloud components with cryptographic algorithms to create user sharing [6].

In Europe the relationship between blockchains and the General Data Protection Regulation (GDPR) is somewhat controversial. On one hand, blockchains seem to represent a good alignment with GDPR (when it comes to data portability, as an example, or consent management, data traceability and lawful access auditability). On the other hand, various issues can be identified (when it comes to right to be forgotten, but also when the technical implementation through smart contracts might weaken the actual control over data, through automatic execution). One option to tackle this issue is ‘dynamic consent management’, which is fully in line with the GDPR provision regarding consent [7]. In addition, it is considered that ‘private blockchains’, e.g., Enterprise Blockchain can easily comply with GDPR directives since the transactions of the digital records of the stored information can be modified and erased by private entities or authorities who can own and control this platform, using a particular class of consensus algorithm [8]. These private blockchains are run by a single company or organization, but they grant access to users, typically organizations, that fulfill certain pre-established credentials or criteria [9]. Such systems would be similarly managed in terms of how a company manages its private web applications. Their use cases could include the following: record keeping by government agencies, public health records owners, and healthcare reimbursement providers. In the future, these private blockchains could have the most significant impact on healthcare policy and management. The potential of blockchains is also addressed by the European Commission Research & Innovation Program IMI (Innovative Medicine Initiative) Pilot project named “Blockchain Enabled Healthcare” lead by Novartis, which aims to leverage existing standards, such as Ethereum, and to develop complementary standards if required. The focus is on enabling services that directly benefit patients [10].

Personal life-log data recently has begun to be captured through wearable sensors or medical IoT devices as personal health records (PHR). Real-time artificial intelligence (AI)-powered healthcare analytics will be fed back to the related users, including patients, physicians, pharmaceutical researchers, and payers [1112]. This entire PHR service trajectory is becoming a valuable source of data for blockchain service providers. (Figure 2).

Distributed or decentralized applications (Dapps) developed on the blockchain enable physicians and patients to easily participate in telemedicine with no middleman costs aside from the minimal fees of the Ethereum network, thus enhancing patient empowerment.

According to Timi Inc., which is a blockchain platform company, an individual patient's data is estimated to be worth as much as USD 7,000 per year [13]. Most of the mHealth companies developing blockchain services target the potential of patients to own and sell their health data with a focus on personal Electronic Health Records (EHRs) and wellnessroutine profiles gathered by wearable sensors, as well as the personal (at-home) genome [14]. Therefore, many consumer companies have been offering DNA sequencing for some time. The company ‘23andMe’, which was founded in 2006, is the most prolific, offering direct-to-consumer genetic testing services [15]. However, privacy is a major issue in the healthcare industry. Last year, 23andMe announced that they had sold a USD 300 million stake in the company to the pharmaceutical giant GlaxoSmithKline, effectively handing over access to the 5 million customers' data, despite it only containing exome data. To address such future concerns, blockchain startups in healthcare claim to offer a solution for consumers wanting to have a DNA test done, while keeping data ownership. They offer the option of data monetization through blockchain-supported providers. For example, a startup called Nebula Genomics is offering whole-genome sequencing for free, as a way to stock up for its real ploy: a blockchain-based genetic marketplace [16]. Once users have their genome sequenced, they can charge a fee, in tokens, to anyone who wants to access it. Thereafter, those tokens can be redeemed for additional tests and products that will further interpret DNA. Genomes.io is another genomics blockchain company that allows consumers to securely store their genome from the moment it is sequenced and subsequently grant access selectively. The idea is to prevent genetic information getting into the wrong hands, while giving consumers the opportunity to sell their genetic data bit by bit if they wish to do so [17].

Blockchain technology is also a viable choice for personal EHR management. So-called ‘smart contracts’, could allow patients to be remunerated with tokens for their sharing of health data with providers and their research partners. For example, Health Wizz is piloting a blockchain- and FHIR-enabled EHR aggregator mobile app, which uses blockchains to tokenize data, enabling patients to securely aggregate, organize, share, donate, and/or trade their personal medical records [18]. The idea is to enable individuals to control their health data as easily as they do their online bank accounts to allow better communication between healthcare organizations and caregivers to pave the way for a higher standard of care.

As an EHR blockchain company, Medicalchain is working on enabling various healthcare agents, such as doctors, hospitals, laboratories, pharmacists, and insurers, to request permission to access and interact with patients' medical records [19]. Each interaction is auditable, transparent, and secure and is recorded as a transaction on Medicalchain's distributed ledger.