How OneLondon is putting data to good use to aid patient services

Healthcare organizations collect huge amounts of data that can be used to improve operational processes and save patient lives. However, exploiting this data is easier said than done. Healthcare professionals face multiple challenges, from stove-piped data to governance hurdles, as they look to turn information into insight.

It’s in this challenging environment that Dr Joe Zhang, CTO at OneLondon, is aiming to create a new era of interoperability. OneLondon is a specialist healthcare partnership that connects health and care information across the capital to improve patient treatments and plan future medical services – and at the heart of this approach sits the Snowflake data platform.

“The data is a lot more complicated in healthcare than [in] other settings; it's highly dimensional, it's multimodal, meaning that you have structured data, free text, but also imaging data, and genomics data,” says Zhang.

“The value of the data for improving care is enormous, but what you're dealing with on the ground is just a constellation of many siloed systems locked away and managed by different teams.”

Disparate data

Patient data in London is spread across GPs, hospitals, mental health providers, community services, and social care organizations. However, this data has traditionally been fragmented across disparate systems, making it difficult to create a joined-up view of patient health to predict demand or conduct population health research.

After an open procurement process that considered other data platforms, OneLondon selected Snowflake, with Zhang suggesting the provider’s capabilities meant its technology ticked more boxes than its rivals. Today, Snowflake is helping the organization solve its data interoperability challenges.

“At a local level, the platform is the layer where we can ingest data that's compliant, secure, and that we can trust,” he says. “It’s also operationally open, which means we can use our own tooling, which is standard things like SQL and Python, to transform data, ingest it, observe it, standardize it, and turn it into a usable asset for clinicians and analysts on the ground.”

Zhang, who spoke with ITPro at the recent Snowflake Summit 2026 in San Francisco, says the platform provides a data mesh-like approach, where professionals can share insights securely with others. As a doctor who used to work in the Intensive Care Unit (ICU), Zhang has first-hand experience of the life-changing impact of timely insights. Now, he’s helping professionals in other healthcare organizations to exploit their data.

“My background is as a doctor, but I've got a technical background in data engineering and data science. I left medicine after COVID. I worked in industry for a while doing biomarker development in real-world data, then came back to London to lead part of the program across London, and then stepped into the CTO role,” he says.

“This job gives me the best of both worlds. We can make a bigger impact with data, data products, and applications built on data, but it can take a bit longer to see the impact. When I worked in [the] ICU, you’d see the results within 10 minutes or so. This work involves a wider scope and longer timelines, but a potentially bigger impact.”

A data journey heading towards value recognition

OneLondon’s activity covers about 30 hospitals and more than 1,400 GP practices. Some healthcare organizations are more mature in their data journey than others. While the Snowflake platform provides a core layer for joined-up analytics efforts, the key to long-term success is ensuring that professionals recognize its value.

“It’s more of an incentivized play rather than saying, ‘This is the pattern we're going for,’” says Zhang. “The organizations that have come on to Snowflake have done so because they think the technology helps with interoperability. A lot of the work has been about unifying opinions across all the organizations in London to make this approach work.”

The key benefit for professionals is a single patient record. Whether someone spends time in GP services, local hospitals or specialist healthcare centers, Zhang says their pathway is tracked: “If you're a clinician at a point of care, you can start to build applications that say, ‘This patient, based on everything that has happened, is at more risk of renal dysfunction, so we should do something about it.’”

Work on the platform continues. The major migration process finished in April, with primary care data feeds currently coming online. At least a dozen use cases are in development. While these pioneering projects will produce benefits, Zhang says it’s important to recognize that the core focus so far has been perfecting the underlying technology layer.

“There are all sorts of infrastructure and networking challenges you must overcome before you think about integration,” he says.

“But because Snowflake offers an application layer where you can provision resources and scale compute to applications that are deployed, it becomes a highly secure solution for us to deploy all sorts of services.”

That effort is crucial, as Zhang says ambitious projects in population health or life sciences research won’t be scalable if the right data isn’t available. The long-term aim of this initiative is to create proactive care applications for clinical pathways: “The approach we choose may not work at first, but you iterate, and create a cycle where you constantly learn and improve.”

Future innovation

Another long-term objective, says Zhang, is to use the joined-up view on data to help support the development of new drugs for disease treatments. He says a key reason the UK isn't doing as well as it could in terms of developing new therapies for patients is a lack of data. The Snowflake platform could play a crucial role in supporting progress.

“We don't know what diseases are there, who is suffering from what disease, and what the trajectories are,” he says.

“So being able to map that process out, being able to run more clinical trials in this country, and getting new drugs to patients faster, would be a big outcome for me if we can help do that.”

Reflecting on progress made so far, Zhang says clear long-term objectives and a trusted technology partner are critical to success. As someone well-versed in life-changing decisions in high-pressure environments, he recognizes that digital leaders looking to push data-enabled change must walk before they can run.

“Often it's not sophisticated things like AI and agents; it's just having the right data in the right place at the right time,” he says.

“We need to be able to measure outcomes and see what's happening to our patients. Those things sound simple, but they've never really been possible before. So, in that instance, this project is all about trying to prevent preventable things.”