Intended for healthcare professionals


Bitcoin technology could take a bite out of NHS data problem

BMJ 2018; 361 doi: (Published 08 May 2018) Cite this as: BMJ 2018;361:k1996
  1. Stephen Armstrong, freelance journalist
  1. London, UK
  1. stephen.armstrong{at}

Blockchain recording of digital transactions could have many healthcare applications—from patient records to tracing pills—reports Stephen Armstrong, but is its potential overhyped?

The cryptocurrency boom may be over, according to recent reports,1 but interest in its underlying technology, the blockchain, is far from it. Digital health experts are starting to wonder if blockchain could solve NHS data problems, and the UK’s first trial of blockchain technology to create and support electronic health records will begin in July at a southwest London general practice group (box 1).8

Box 1

Blockchain examples in health

Countering counterfeits

“The blockchain provides a granular trail of a product’s journey,” explains Peter Bryant, chief operating officer of UK based global drug tracking system FarmaTrust. With the Drug Supply Chain Security Act in the US rolling out between 2015 and 2023,2 and the equivalent Falsified Medicines Directive in the EU coming into force next spring,3 all pharmaceutical products will require a label with a unique serial number, name, lot number, batch number, and expiry date. FarmaTrust is talking to 13 manufacturers as well as the Mongolian government to offer a blockchain tracking system that can link with existing databases. The company is also working with medicinal poppy and marijuana growers and the government in Thailand to ensure that products are traceable and the farmers are taxed on profits.

Patient records

Technology company Medicalchain is partnering with southwest London general practice group, The Groves, in the UK’s first trial of blockchain to create and support electronic health records.4 It offers registered patients a free digital wallet to hold and manage access to their health records. The platform includes a cryptocurrency—Medicalchain’s MedTokens—to encourage patients to participate, which they can use as private patients to pay for telemedicine services.

Elsewhere, MIT research project MedRec is trialling a health records system that leaves patient records in hospitals or GP surgeries but offers what is effectively an electronic card catalogue. This connects every intervention or treatment on each record, allowing clinicians to identify and access patients’ medical history wherever it is stored. Raw medical record content “is never stored on the blockchain, but rather kept securely in providers’ existing data storage infrastructure,” according to the team.5 MedRec automatically keeps track of who has permission to view and change the record of medications a person is taking and rewards bitcoin-style “miners”—generally medical researchers and healthcare professionals—with access to aggregated, anonymised data for epidemiological studies.

American startup SimplyVital Health’s Connecting Care works in a similar way6 while, in the UK, Healthchain7 also plans to connect health data with researchers.


Blockchain technology was originally invented by bitcoin creator, Satoshi Nakamoto, in 2009, to support the launch of his cryptocurrency. (Cryptocurrency is essentially a snippet of code that represents ownership of a digital concept, like a virtual “IOU” that can be exchanged online). There can be any number of blockchains—Nakamoto’s was designed to solve the problem of devising a new currency backed by no central banks or governments.

How blockchain works

Each blockchain is, in effect, a giant decentralised electronic ledger—a record of transactions with duplicate copies held on thousands of computers around the world. “Miners”—people who agree to let their computers be used in the blockchain—are rewarded with cryptocurrencies such as bitcoin.

All these duplicate digital records held on those thousands of computers compare and confirm each transaction. The resulting record is lumped together into “blocks” then encoded to prevent hacking and chronologically bound together into a “chain.” This encryption process, known as “hashing” is carried out by every computer on the network. If they all agree, each block receives a unique digital signature. If not, the transaction fails.

Anyone looking to alter a transaction would need to manipulate every supporting computer and, unless they sought changes instantly, would have to sift back through overlaid changes to find it. As a result, no transaction recorded can be altered or deleted—it’s an irrefutable record that allows ownership and transfer of assets without the need for trusted third parties. It’s proof not just of ownership but of provenance.

“Because the blockchain constantly moves forward, it stops you denying tomorrow what you said yesterday,” explains Sam Smith, spokesperson for medical data privacy lobbying group MedConfidential. “You can say you were wrong but you can’t say you didn’t say it, which could be useful in many ways, from patient records to tracing pills.”

Beyond bitcoin

It didn’t take long for people to realise that these properties of blockchain are useful beyond bitcoin. In a January 2016 report,9 Mark Walport, the UK government’s chief scientific adviser, argued that blockchain technology could expand far beyond a trading tool. “Distributed ledger technologies have the potential to help governments collect taxes, deliver benefits, issue passports, record land registries, assure the supply chain of goods, and generally ensure the integrity of government records and services,” the report concluded.

In healthcare, researchers are looking at blockchain to track medicines around the world, to store patient health records, and to monitor how patient data are changed. For Navin Ramachandran, a consultant radiologist at University College London Hospital and faculty member of the UCL Centre for Blockchain Technologies, the possibilities are immense. Ramachandran is a healthcare adviser to the IOTA Foundation, a non-profit organisation based in Germany that promotes open source distributed ledger technologies.

“Many healthcare records are stored electronically in the cloud these days, which makes it much easier for hackers to find a lot of confidential information,” he argues. “Sharing data like health records has been tricky across the NHS as it’s hard to connect hospitals with different systems—so private data providers operate systems that aggregate or store data.

“Patient information on paper was hard to get hold of but difficult to tamper with. Now it’s easier to get hold of, but a small group of people control all the data and can modify it.”

The vanguard

Since last summer, the foundation has been working with the Norwegian government10 to set up a public ledger encrypted in the cloud, to allow citizens to control their health data and allow access rights to individuals or institutions as the citizen sees fit. “Artificial intelligence and precision medicine both rely on data to make potentially life altering decisions,” says Ramachandran.

“Securing the integrity of the data will become ever more important—that can be a system controlled by private companies or a system controlled by citizens. I’d prefer it to be the citizens, although the vastness of the ledger makes a public chain slow to update.”

One private company that’s working on blockchain technology is Google sister company DeepMind. It is developing a version of blockchain called a verifiable data audit,11 which will track any interference with information stored on the company’s systems, in a bid to head off concerns raised last year over its handling of patient data at Royal Free NHS Foundation Trust.12

“It’s slightly different from the blockchain, which stores every transaction through data sharing,” explains Andrew Eland, head engineer at DeepMind. “That establishes openness through the sheer amount of work taken to change the record.

“We want to verify who did what with patient data so we’re building a slightly different system. Every interaction with patient data will be logged in a private ecosystem that either includes or can be easily accessed by trusted public bodies like the data guardian or the Medicines and Healthcare Products Regulatory Agency.”

Overblown claims?

For some digital health experts, the claims made for blockchain are overblown. “Blockchain is a data storage and verification technology, which has some advantages over other data storage technologies, although it has some disadvantages like its high energy usage. Cryptomining now uses a substantial proportion of the world’s electricity supply,”13

says Marcus Baw, GP and founder of, a coalition of forums for digital health.

“But, overall, it’s a database. NHS technology, as provided by NHS Digital, is so archaic and out of date that we are struggling with simple IT tasks like sharing the right data about the right patient, to the right care setting, at the right time.

“Blockchain will not make any impact in the NHS for the foreseeable future. Maybe one day, when the hype’s died down and we will have found out which few tasks blockchain is uniquely suited to, we will find blockchain based applications in real life usage in the NHS. But right now, it’s a solution in search of a problem,” Baw says.

James Somauroo, a former intensive care specialist who cofounded the health digital accelerator company HS, is more positive but thinks blockchain evangelists have a lot to prove. “What matters to the people in the NHS is not the tech you use but what problem do you solve,” he argues.

“With blockchain it’s still a very tech led conversation. What we need to see this year is one clear demonstration of how blockchain has solved a small problem—there are lots of trials but the NHS is on its knees, so it needs evidence that the blockchain can do a better, cheaper job.”


  • Competing interests: I have read and understood BMJ policy on declaration of interests and have no relevant interests to declare.

  • Provenance and peer review: Commissioned; not externally peer reviewed.


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