The pharmacoepidemiological research group at University of Southern Denmark is an internationally recognized research group with more than 30 years of experience in register-based research. The research group uses primarily the Danish health registries to examine utilization patterns as well as desired effects and adverse drug reactions when using prescription drugs.
The research groups use epidemiological, statistical, and data-science methods to study the utilization, safety, and potential benefits of medicines in routine clinical practice. Research is primarily based on linked healthcare data, including prescription records, hospital diagnoses, laboratory results, and demographic information.
The methodological portfolio includes cohort, case-control, nested case-control, new-user, active-comparator, and interrupted time-series designs. The groups have particular expertise in self-controlled methods, including case-crossover, case-time-control, self-controlled case series, and prescription symmetry analysis, as well as methods for studying cumulative drug effects.
Large-scale screening is used to investigate multiple drug–outcome and drug–drug associations systematically, covering both adverse effects and potential collateral benefits. This work incorporates signal prioritization, replication across databases and study designs, and comparison of immediate and cumulative effects. Simulation studies and empirical evaluations are used to assess bias, exposure misclassification, and statistical precision.
We develop methods, infrastructure, and practice within pharmacoepidemiology
This involves improving existing analysis methods or developing new ones, as well as holding courses, sharing codes, and publishing tutorials and supporting material for other researchers. In addition, the group is extremely active in both the Danish Society for Pharmacoepidemiology, in the Nordic network for Pharmacoepidemiology, and in the International Society for Pharmacoepidemiology.
In addition to method development, the group is widely recognized for applied pharmacoepidemiological research within virtually all therapeutic areas, i.e. studies of specific drug effects, with the aim of creating knowledge that can be used by clinicians, patients, and regulators.
Our research interests are broad and are currently falling into these specific categories:
- Practices for hypothesis-free screening of big data
- Methods development within pharmacoepidemiology
- Pediatric pharmacoepidemiology
- Geriatric pharmacoepidemiology
- Women's health
- Cancer pharmacoepidemiology
Our partners:
Center for Pharmaceutical Data Science Education: based at the University of Copenhagen, the aim is to integrate data science into pharmaceutical education at the Bachelor’s, Master’s, PhD, and continuing education levels
SIGMA consortium: A European network that facilitates regulatory work between pharmaceutical manufacturers and scientific partners with access to real-world data, with the objective of addressing regulatory scientific questions.
Odense University Hospital, Hospital Pharmacy Funen
About the research group leaders Anton Pottegård and Jesper Hallas
Jesper Hallas is Professor of Clinical Pharmacology at the University of Southern Denmark and an internationally recognized expert in pharmacoepidemiology, drug safety, and drug-utilization research. He established his pharmacoepidemiological research programme in the late 1980s and founded the Odense University Pharmacoepidemiologic Database, one of the early prescription databases developed specifically for research. His work combines large-scale observational data with methodological innovation to study adverse drug effects, patterns of medicine use, and previously unrecognized beneficial or harmful drug effects.
Professor Hallas has made important contributions to self-controlled study designs, symmetry analysis, modelling of prescription waiting-time distributions, individual-level drug-utilization analysis, and methods for screening large healthcare databases. He has published more than 500 PubMed-indexed papers and has supervised or co-supervised 36 completed PhD theses. He has attracted more than €20 million in external research funding, primarily for post-authorisation safety studies.
His international recognition includes serving as President of the International Society for Pharmacoepidemiology and holding a visiting professorship at Brigham and Women’s Hospital and Harvard Medical School. His research is rooted in extensive clinical experience and specialist training in internal medicine, gastroenterology, and clinical pharmacology. He co-leads a large multidisciplinary pharmacoepidemiology research environment involving epidemiologists, statisticians, managers, and doctoral researchers.
Anton Pottegård is Professor of Pharmacoepidemiology at the Department of Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark, heading the pharmacoepidemiology unit alongside Jesper Hallas. He is trained as a pharmacist and has published more than 400 peer-reviewed papers.
His research uses the Danish nationwide health registries to study drug utilisation, medication safety, and the effects of prescription drugs in routine care. As examples of his work, he has showed that hydrochlorothiazide increases the risk of skin cancer, which led to updated product information across Europe. He also described a clinically important interaction between dicloxacillin and warfarin, and led DACCOVID, a Danish register-based research collaboration during the COVID-19 pandemic.
He works on transparency and reproducibility in real-world evidence (www.RWERR.com). He collaborates with the Danish Medicines Agency, the Danish Health Authority, and the Danish Health Data Authority. He is a Fellow of the International Society for Pharmacoepidemiology (ISPE).
Anton gives high priority to communicating research outside academia, in particular via social media, to patients, clinicians, and the public. In 2026 he received the Danish Research Communication Prize (Forskningskommunikationsprisen).