Sean Hennessy

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Professor of Epidemiology in Biostatistics and Epidemiology
Senior Fellow, Leonard Davis Institute of Health Economics, University of Pennsylvania
Fellow, Institute on Aging, University of Pennsylvania
Senior Scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania Perelman School of Medicine
Founding Director, Center for Pharmacoepidemiology Research and Training (CPeRT), University of Pennsylvania Perelman School of Medicine
Investigator, Center for Pharmacoepidemiology Research and Training (CPeRT), University of Pennsylvania Perelman School of Medicine
Member, Abramson Cancer Center, University of Pennsylvania Perelman School of Medicine
Department: Biostatistics and Epidemiology

Contact information
University of Pennsylvania
423 Guardian Drive
803 Blockley Hall
Philadelphia, PA 19104-6021
Office: 215-898-9112
Fax: 215-573-5315
Graduate Group Affiliations
BS (Pharmacy)
Philadelphia College of Pharmacy and Science, 1989.
PharmD (Clinical Pharmacy)
Philadelphia College of Pharmacy and Science, 1990.
MSCE (Clinical Epidemiology)
University of Pennsylvania School of Medicine, 1996.
PhD (Epidemiology with Biostatistics minor)
University of Pennsylvania, 2002.
Post-Graduate Training
Fellow in Clinical Epidemiology, Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, 1991-1996.
Senior Research Investigator, Department of Biostatistics and Epidemiology, Perelman School of Medicine at the University of Pennsylvania, 1997-2000.
American College of Epidemiology, 2001.
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Description of Research Expertise

Sean Hennessy leads Penn's Center for Pharmacoepidemiology Research and Training (CPeRT), and conducts research in the field of pharmacoepidemiology, which is the study of the health effects of drugs and other medical products in populations. He and his colleagues identified a survival benefit of potassium supplementation in users of loop diuretics, and found that this survival benefit increases with hotter outdoor temperature. They also found that the survival benefits of statin drugs increases with hotter outdoor temperature. He and his colleagues study serious health consequences of drug-drug interactions involving high-risk drugs including anticoagulants, antidiabetes drugs, and antiplatelet agents. Their research has produced actionable knowledge about the cardiovascular safety of many widely-used drugs for mental health conditions in including ADHD, depression, and schizophrenia. They also evaluated an early approach 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 developed the trend-in-trend research design for studying the effects of rapidly increasing or declining exposures. 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 persons with mild to moderate renal insufficiency. He has served as chair of NIH's Health Services and Organizational Delivery study section and Health Services Quality and Effectiveness study section.

Selected Publications

Flannery D, Passarella M, Mukhopadhyay S, Dhudasia M, Gerber J, Lorch S, Hennessy S, Puopolo K: Early childhood antibiotic utilization for infants discharged from the neonatal intensive care unit. Journal of Perinatology 2022 (

Shah M, Marmarelis ME, Mamtani R, Hennessy S: Association between survival and very high versus high PD-L1 expression in patients receiving pembrolizumab as first-line treatment for advanced non-small cell lung cancer. Clinical Lung Cancer 2022 (

Miano TA, Hennessy S, Yang W, Dunn TG, Weisman AR, Oniyide O, Agyekum RS, Turner AP, Ittner CAG, Anderson B, Wilson FP, Townsend R, Giannini HM, Cosgriff CV, Jones TK, Meyer NJ, Shashaty MGS: Association of vancomycin plus piperacillin-tazobactam with early changes in creatinine versus cystatin C in critically ill Adults: a prospective cohort study. Intensive Care Medicine 2022 (

Shah M, Hubbard RA, Mamtani R, Marmarelis ME, Hennessy S: Very high PD-L1 Expression as a prognostic indicator of overall survival among Patients with advanced non-small cell lung cancer receiving anti PD-(L)1 monotherapies in routine practice. Pharmacoepidemiology and Drug Safety 2022 (

Miano TA, Wang L, Leonard CE, Brensinger CM, Acton EK, Dawwas DK, Bilker WB, Soprano SE, Nguyen TPP, Woody G, Yu E, Neuman M, Li L, Hennessy S: Identifying clinically relevant drug-drug interactions with methadone and buprenorphine: a translational approach to signal detection. Clinical Pharmacology and Therapeutics 2022 (

Dhopeshwarkar N, Yang W, Hennessy S, Rhodes JM, Cuker A, Leonard CE: Rate of major bleeding with ibrutinib versus bendamustine-rituximab in chronic lymphocytic leukemia: a population-based cohort study. American Journal of Hematology 2022 (

Chen C, Hennessy S, Brensinger CM, Dawwas GK, Acton EK, Bilker WB, Chung S, Dublin S, Horn JR, Miano TA, Pham Nguyen TP, Leonard CE: Skeletal muscle relaxant drug-drug-drug interactions and unintentional traumatic injury: Screening to detect three-way drug interaction signals. British Journal of Clinical Pharmacology 2022 (

Dawwas GK, Hennessy S, Brensinger CM, Acton EK, Bilker WB, Chung S, Dublin S, Horn JR, Manis MM, Miano TA, Oslin DW, Pham Nguyen TP, Soprano SE, Wiebe DJ, Leonard CE: Signals of muscle relaxant drug interactions associated with unintentional traumatic injury: A population-based screening study. CNS Drugs 2022 (forthcoming).

Dawwas GK, Cuker A, Rothstein A, Hennessy S. : Trends in post-discharge prophylactic anticoagulant use among stroke patients in the United States between 2006 and 2019 Journal of Stroke and Cerebrovascular Diseases 2022 (epub ahead of print).

Dawwas DK, Flory JH, Hennessy S, Leonard CE, Lewis JD: Comparative safety of sodium glucose co-transporter-2 inhibitors versus dipeptidyl peptidase-4 inhibitors and sulfonylureas on the risk of diabetic ketoacidosis. Diabetes Care 2022 (doi: 10.2337/dc21-2177).

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Last updated: 08/17/2022
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