Description of Research Expertise

Sean Hennessy leads Penn's Division of Epidemiology and its Center for Real-world Effectiveness and Safety of Therapeutics (CREST). His research evaluates the real-world effectiveness and safety of prescription drugs using healthcare data. His research program studies serious health consequences of drug-drug interactions involving high-risk drugs including anticoagulants, treatments for diabetes, and medications used for opioid use disorder, and is widely cited in clinical compendia of drug-drug interactions. He and his colleagues identified a survival benefit of potassium supplements in users of loop diuretics, and found that this survival benefit increases with hotter outdoor temperatures. They also found that the survival benefit of statin drugs increases with hotter outdoor temperatures. His team also evaluated an early approach, known as drug utilization review, to using health insurance data to improve prescribing, finding it ineffective despite its federal mandate. This contributed to the omission of a requirement for drug utilization review programs in Medicare Part D. He co-led a pair of studies that demonstrated the effectiveness and safety of the SA14-14-2 vaccine for Japanese encephalitis (JE), which subsequently led to the immunization of millions of children per year in populous countries including Cambodia, India, Malaysia, Nepal, Sri Lanka, and Thailand. Use of that vaccine has been credited with reducing the worldwide incidence of JE. He and his colleagues also developed the instrumented difference-in-differences research design for studying the effects of exposures with marked time trends. He was the senior author of one of two citizen petitions to the US Food and Drug Administration that led to re-labeling of metformin, the best-proven therapy for type 2 diabetes, to permit its use in the millions of persons with both diabetes and mild-to-moderate renal insufficiency. He has served as chair of NIH's Health Services and Organizational Delivery study section and its Health Services Quality and Effectiveness study section.