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Term of the Day

Natural history study

A natural history study is a preplanned observational study intended to track the course of a disease over time, identifying demographic, genetic, environmental and other variables that correlate with its development and outcomes in the absence of intervention, or under standard of care. Designs may be retrospective (chart review of existing records) or prospective (longitudinal follow-up of a cohort or registry).

Natural history data is particularly important in rare and paediatric diseases, where randomised placebo-controlled trials may be infeasible or unethical. The FDA (guidance on rare disease natural history studies, 2019) and the EMA accept well-designed natural history studies to define endpoints and biomarkers, identify patient subgroups, estimate sample sizes and, in some cases, serve as external or historical control arms for single-arm trials supporting orphan products.

Because they are non-interventional, natural history studies fall outside the CTR and are governed by national law (for example France's MR-003 or MR-004 reference methodologies) and by the GDPR. They typically involve secondary use of medical records, long-term follow-up, genetic data and small populations in which anonymisation is rarely achievable, so pseudonymisation, a DPIA and a robust research legal basis under Art. 9(2)(j) are essential. Registries maintained by patient organisations or academic consortia raise additional questions of joint controllership and data access governance.

U

Imported item 43

The US CLOUD Act is a 2018 law addressing access to electronic evidence across borders. It clarifies that providers subject to US jurisdiction can be required, through applicable legal process, to disclose data within their possession, custody or control even when those data are stored outside the United States.

Key takeaways

  • Server location alone does not settle jurisdiction.
  • The Act does not create unrestricted access.
  • A foreign order is not itself GDPR permission.

What the Act Changes

The US Department of Justice explanation distinguishes provider disclosure obligations from the Act’s framework for bilateral agreements on electronic evidence. For hosting assessments, keep those mechanisms separate.

IssueOperational meaning
LocationOverseas storage does not automatically exclude US process.
ControlCheck which entity holds or controls the information.
ProcedureDisclosure remains subject to applicable legal process.

Why It Matters for Data Protection

The EDPB’s Article 48 guidelines explain that foreign decisions are not automatically enforceable in the EU. A transfer responding to a foreign authority needs an appropriate processing basis and compliance with GDPR international-transfer requirements. An international agreement may be relevant, but its existence and coverage must be assessed rather than assumed. Other Chapter V routes require their own analysis.

Hypothetical example: A sponsor considers an EU-hosted platform operated by a group with US connections. We recommend reviewing corporate roles, access privileges, encryption-key control and the provider’s process for scrutinising requests. The team records the residual risk instead of equating a European data centre with immunity from foreign legal demands.

Frequently Asked Questions

Does the CLOUD Act allow routine browsing of all cloud data?

No. Its disclosure mechanism operates through applicable legal process.

Does EU hosting remove every exposure?

No. Jurisdiction and possession, custody or control also matter.

Is every disclosure to a foreign authority prohibited?

No. Analyse the processing basis, transfer route and applicable agreement or safeguard.

Related reading: third country, health-data sovereignty and hosting. For practical support, see clinical data hosting.

Updated: 27 October 2026