Intended for healthcare professionals

Feature Essay

Blockchain’s potential to improve clinical trials—an essay by Leeza Osipenko

BMJ 2019; 367 doi: (Published 03 October 2019) Cite this as: BMJ 2019;367:l5561
  1. Leeza Osipenko, senior lecturer in practice, London School of Economics and Political Science, and visiting fellow, Center for Global Development
  1. London
  1. l.osipenko{at}

There’s more to this tamperproof technology than bitcoin. It could be used to improve the administration of clinical trials, ensuring transparency and yielding better quality data, writes Leeza Osipenko

Blockchain is the digital technology that underpins cryptocurrencies such as bitcoin (box 1). In essence it uses cryptography to guarantee that multiple sets of the same data, held by separate users, are identical.

Box 1

What are blockchains and smart contracts?

Blockchain is a way of managing data that prevents their manipulation.1 A new “block” of data records each specific event. Each block is time stamped and includes cryptographic information (a “hash”) from the previous block. These hashes link blocks securely to form chains, making data modification impossible without changing the entire chain.

All users in a network have their own copy of the blockchain. This decentralisation of data enables transparency and further security, because any modification has to be sanctioned by all users.1 Current, centralised ways of managing data lack such assurance.

Blockchain cannot protect from errors when data are entered, but it can ensure the provenance of data and improve transparency. Erasing blockchain data is impossible, so data can be updated or modified only by adding new blocks, and any obsolete blocks will remain.

Smart contracts are versatile computer algorithms mandating that all users follow prespecified rules for a given task,1 without the need for centralised supervision or inspection. For example, smart contracts could replace many activities in auditing clinical trials. Currently, auditors ensure that specific documents are in order before an investigator can begin a trial. A smart contract could be coded to mandate that patient enrolment cannot begin before all documents are uploaded.

Blockchain’s underlying technical features make no difference to users, who interact with a conventional web based interface for entering and retrieving data.


Blockchain’s applications in finance have given it …

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