The OHDSI community is launching the fifth edition of Phenotype Phebruary, a month-long global initiative dedicated to advancing the way we build and evaluate clinical phenotypes. This year’s event centers on a high-stakes community experiment: a collaborative "Phenotype Challenge" where participants will focus on a single clinical condition. The goal is to move through an end-to-end, iterative development cycle that combines human expertise with cutting-edge tools to establish a gold standard for phenotype definitions within the OMOP Common Data Model.

The primary objective of this year’s initiative is to test a systematic, AI-assisted workflow. By integrating LLMs with established OHDSI tools like KEEPER and CohortDiagnostics, the community aims to explore how reasoning models can enhance phenotype development, evaluation, and refinement. This experiment has the potential to significantly improve the accuracy and scalability of clinical research, providing a roadmap for generating high-quality evidence across diverse observational data sources worldwide.

Participation is open to all members of the OHDSI community, regardless of their level of expertise. Collaborators can get involved by voting on the target condition, submitting phenotype definitions—whether rule-based, machine learning-based, or hybrid—and participating in the iterative refinement process based on data-driven feedback. Data partners are also encouraged to run definitions locally to strengthen the generalizability of the results. Weekly Phenotype Workgroup calls and community updates will provide ongoing support and insights throughout the month of February.

Ilse Vermeulen works at the intersection of real-world data, health system transformation, and multi-stakeholder collaboration. Originally trained as a bioengineer, she earned a PhD in Medical Sciences from the Vrije Universiteit Brussels and developed her expertise in large-scale health data ecosystems later in her career through hands-on practice and community-driven learning within the OHDSI ecosystem, under the mentorship of Prof. Liesbet M. Peeters. Her work focuses on enabling collaboration across institutions and disciplines to make health data more interoperable, trustworthy, and usable for research and decision-making.

She serves as the National Node Manager of OHDSI Belgium, where she helps connect Belgian hospitals, researchers, and partners to the broader OHDSI community in Europe and beyond. Known for her versatility and ability to navigate complexity, Ilse brings together technical understanding, coordination, and community building to support federated research and real-world evidence generation. From January 2026 onward, she joined the Medical Informatics team at Erasmus MC as a Project Manager, contributing to the coordinating centers of OHDSI Europe and DARWIN EU. Across her roles, she is driven by the belief that meaningful innovation in healthcare emerges not from silos, but from sustained collaboration across people, systems, and perspectives.

In the latest edition of the Collaborator Spotlight, Ilse discusses her career journey, her work with the Belgian National Node and the 2025 Europe Symposium, the future possibilities for European healthcare, and plenty more.