Hans de Vries' research focuses on diabetes technology, glucose regulation in the hospitals and improving treatment of diabetes types 1 and 2 as well as gestational diabetes. He is working on the development of an artificial pancreas to automate the administration of insulin. His research on improved treatment of type 2 diabetes is mainly aimed at using glucagon-like peptide receptor agonists. He is also investigating the use of continuous glucose monitors in pregnant women with diabetes and the use of oral glucose-lowering medication as an alternative to insulin in gestational diabetes, in collaboration with the national obstetrics and gynaecology consortium.

De Vries teaches courses in the Medicine, Internal Medicine and Endocrinology curricula, as well as refresher courses for diabetes nurses and general medical practice support staff.

De Vries specialises in internal medicine and endocrinology, and is a principal investigator at the AMC-UvA. He is the leader of the PCDIAB Consortium, and previously directed the AP@home Consortium, both of which are European research projects working on the development of an artificial pancreas. In addition, he is programme adviser for the annual European Advanced Technologies and Treatments for Diabetes meeting and a member of the editorial boards of two scientific journals: Diabetes Technology & Therapeutics and the Journal of Diabetes Science and Technology.