About

Patrick J. Brennan, MD, is a Professor of Medicine (Infectious Diseases) at the Hospital of the University of Pennsylvania and an Attending Physician at the same institution. He holds a secondary appointment as a Professor at the University of Pennsylvania School of Nursing. Dr. Brennan is also an Affiliate Member of the Center for Clinical Epidemiology and Biostatistics at the University of Pennsylvania School of Medicine. He serves as Chair of the Risk/Quality/Safety Subcommittee of the UPHS Professional Liability Oversight Committee and is a member of the Board of Trustees at the Hospital of the University of Pennsylvania. Additionally, he is the Chief Medical Officer and Senior Vice President of the University of Pennsylvania Health System, and he is involved in various leadership roles within Penn Medicine, including co-chairing the Post-Acute Care Executive Oversight Committee and serving on multiple boards related to Penn Medicine at Home and Good Shepherd Penn Partners.

Research topics

• Biology
• Medicine
• Microbiology
• Biochemistry
• Chemistry

Selected publications

• Robust Dissimilar Metal Friction Welded Spool for Enhanced Capability for Steam Power Components (Final Program Report)

  2024-02-01

  reportOpen access

  This project successfully demonstrated the feasibility and advantages of producing durable, friction-welded dissimilar-metal spools, both with and without transition pieces, as well as the use of advanced oxidation-protective coatings for steam power applications. The work encompassed the optimization and full-scale production of NFA tubing, overcoming manufacturing and processing challenges to achieve enhanced strength, creep, and fatigue properties validated by extensive microstructural characterization. Optimized welding techniques were developed and refined for joining dissimilar materials, resulting in defect-free welds optimized for both low- and high-pressure boiler circuits. Systematic evaluation of welding parameters, coupled with heat treatments, ensured reliable performance and minimized weld defects such as banding and cracking. Comprehensive mechanical and non-destructive testing, including tensile, bend, fatigue, and CT scanning, confirmed the superior integrity and durability of the friction-welded joints under representative service conditions. To address oxidation-related degradation, a range of protective alloy coatings—such as IN625, APMT, Duplex 2507, and FeCrAlY—were selected and evaluated for their ability to counteract oxide notch formation at dissimilar metal interfaces. These coatings demonstrated improved oxidation resistance and long-term stability under thermal cycling, thereby extending weld service life. Thermal cyclic testing and long-term studies captured the phase stability and diffusion behavior of coated and uncoated configurations. Validated models for low-cycle fatigue (LCF), creep, and thermal mechanical fatigue (TMF) were developed to predict component life and failure modes. These models confirmed that friction-welded configurations exhibited significantly enhanced performance compared to conventional gas-tungsten arc welding (GTAW), with up to 7× improvement in creep resistance and at least 2× enhancement in fatigue properties. The introduction of a tailored transition piece further reduced thermally induced strains, enhancing fatigue life. The results demonstrate a robust pathway for retrofitting existing steam fleet components and upgrading future equipment to deliver substantially improved cold-start cycling behavior and reduction of unplanned outages due to premature weld failures.

  PublisherOA PDFDOI

• Tu1154 BUILDING A REMOTE GASTROINTESTINAL CARE NETWORK IN A REGION OF GLOBAL CONFLICT

  Gastroenterology · 2024-05-01

  article
  PublisherDOI

• Providing Remote Aid During a Humanitarian Crisis

  Critical Care Explorations · 2023-10-27 · 6 citations

  articleOpen accessSenior author

  Humanitarian crises create opportunities for both in-person and remote aid. Durable, complex, and team-based care may leverage a telemedicine approach for comprehensive support within a conflict zone. Barriers and enablers are detailed, as is the need for mission expansion due to initial program success. Adapting a telemedicine program initially designed for critical care during the severe acute respiratory syndrome coronavirus 2 pandemic offers a solution to data transfer and data analysis issues. Staffing efforts and grouped elements of patient care detail the kinds of remote aid that are achievable. A multiprofessional team-based approach (clinical, administrative, nongovernmental organization, government) can provide comprehensive consultation addressing surgical planning, critical care management, infection and infection control management, and patient transfer for complex care. Operational and network security create parallel concerns relevant to avoid geolocation and network intrusion during consultation. Deliberate approaches to address cultural differences that influence relational dynamics are also essential for mission success.

  PublisherDOI

• Clinical Predictors of Survival in Probable Dementia with Lewy Bodies (P13-6.006)

  Neurology · 2023-04-25

  article

  To determine clinical predictors of survival from cognitive symptom onset in patients with clinically probable DLB.

  PublisherDOI

• Outcomes and risk factors for failure after débridement, antibiotics, and implant retention for elbow periprosthetic joint infection

  Journal of Shoulder and Elbow Surgery · 2022-12-21 · 9 citations

  article
  PublisherDOI

• Durability of Severe Acute Respiratory Syndrome Coronavirus 2 Messenger RNA Booster Vaccine Protection Against Omicron Among Healthcare Workers With a Vaccine Mandate

  Clinical Infectious Diseases · 2022-06-06 · 25 citations

  articleOpen access

  BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has spread rapidly throughout the world since being identified in South Africa in November 2021. Few studies have assessed primary series and booster vaccine effectiveness against Omicron among US healthcare workers. METHODS: We conducted a test-negative case-control design to estimate BNT162b2 and mRNA1273 primary vaccination and booster effectiveness against SARS-CoV-2 infection and symptomatic coronavirus disease 2019 during an Omicron surge among employees of the University of Pennsylvania Health System. The study period was between 1 July 2021 and 5 April 2022. We defined the Delta period as 1 July to 12 December 2021 and the Omicron period as beginning 12 December 21. RESULTS: Our sample included 14 520 tests (2776 [19%] positive)-7422 (506 [7%] positive) during Delta and 7098 (2270 [32%] positive) during Omicron. Benchmarked against Delta, the vaccine effectiveness of 2 vaccine doses was lower during Omicron, with no significant protection against infection. Booster doses added significant protection, although they also showed reduced effectiveness during Omicron. Compared with findings in employees who had received 2 vaccine doses, 3 doses of BNT162b2 had a relative effectiveness of 50% (95% confidence interval, 42%-56%) during Omicron, relative to 78% (63%-87%) during Delta; 3 doses of mRNA1273 had a relative effectiveness of 56% (45%-65%) during Omicron, relative to 96% (82%-99%) during Delta. Restricting the sample to symptomatic tests yielded similar results to our primary analysis. After initial waning in BNT162b2 booster protection against infection, it remained largely stable for ≥16 weeks after vaccination. CONCLUSIONS: Our findings provide a strong rationale for boosters among healthcare workers in the Omicron era.

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• Biallelic SEPSECS variants in two siblings with pontocerebellar hypoplasia type 2D underscore the relevance of splice-disrupting synonymous variants in disease.

  Molecular Case Studies · 2022-01-28 · 1 citations

  articleOpen access

  Noncoding and synonymous coding variants that exert their effects via alternative splicing are increasingly recognized as an important category of disease-causing variants. In this report, we describe two siblings who presented with hypotonia, profound developmental delays, and seizures. Brain MRI in the proband at 5 years showed diffuse cerebral and cerebellar white matter volume loss. Both siblings later developed ventilator-dependent respiratory insufficiency, scoliosis and are currently nonverbal and non-ambulatory. Extensive molecular testing including oligo array and clinical exome sequencing was non-diagnostic. Research genome sequencing under an IRB-approved study protocol revealed that both affected children were compound-heterozygous for variants in the SEPSECS gene. One variant was an initiator codon change (c.1A>T) that disrupted protein translation, consistent with the observation that most disease-causing variants are loss-of-function changes. The other variant was a coding change (c.846G>A) that was predicted to be synonymous but had been demonstrated to disrupt mRNA splicing in a minigene assay. SEPSECS gene encodes O-phosphoseryl-tRNA(Sec) selenium transferase; an enzyme that participates in the biosynthesis and transport of selenoproteins in the body. Variations in SEPSECS cause autosomal recessive pontocerebellar hypoplasia type 2D (PCHT 2D; OMIM #613811), a neurodegenerative condition characterized by progressive cerebrocerebellar atrophy, microcephaly, and epileptic encephalopathy. The identification of biallelic pathogenic variants in this family- one of which was a synonymous change not identified by prior clinical testing- not only ended the diagnostic odyssey for this family, but also highlights the contribution of occult pathogenic variants that may not be recognized by standard genetic testing methodologies.

  PublisherOA PDFDOI

• Gastroblastoma with a novel <scp><i>EWSR1‐CTBP1</i></scp> fusion presenting in adolescence

  Genes Chromosomes and Cancer · 2021-05-27 · 31 citations

  article

  Gastroblastomas are rare tumors with a biphasic epithelioid/spindle cell morphology that typically present in early adulthood and have recurrent MALAT1-GLI1 fusions. We describe an adolescent patient with Wiskott-Aldrich syndrome who presented with a large submucosal gastric tumor with biphasic morphology. Despite histologic features consistent with gastroblastoma, a MALAT1-GLI1 fusion was not found in this patient's tumor; instead, comprehensive molecular profiling identified a novel EWSR1-CTBP1 fusion and no other significant genetic alterations. The tumor also overexpressed NOTCH and FGFR by RNA profiling. The novel fusion and expression profile suggest a role for epithelial-mesenchymal transition in this tumor, with potential implications for the pathogenesis of biphasic gastric tumors such as gastroblastoma.

  PublisherDOI

• 220 Choice of UK Medical School Predicts Success in The Intercollegiate Membership of The Royal College of Surgeons (MRCS) Examination

  British journal of surgery · 2021-05-01

  articleOpen accessSenior author

  Abstract Background UK medical schools vary in terms of factors such as mission, specific curricula and pedagogy. As relatively little is understood about the impact of these differences at a post-graduate level, we examined the relationship between medical school and MRCS success. Method Using the UKMED database we analysed data on UK medical graduates who attempted MRCS Part A (n = 9729) and MRCS Part B (n = 4644) between 2007-2017. Univariate analysis characterised the relationship between medical school and first attempt MRCS success. Logistic regression modelling identified independent predictors of MRCS success. Results MRCS pass rates differed significantly between medical schools (P &amp;lt; 0.001). Trainees from standard-entry 5-year programmes were more likely to pass MRCS at first attempt compared to those from extended (Gateway) courses ((Part A (Odds Ratio (OR) 3.72 [95% Confidence Interval (CI) 2.69-5.15]); Part B (OR 1.67 [1.02-2.76])). Non-graduates were more likely to pass Part A (OR 1.40 [1.19-1.64]) and Part B (OR 1.66 [1.24-2.24]). Russell Group graduates were more likely to pass MRCS Part A (OR 1.79 [1.56-2.05]) and Part B (OR 1.24 [1.03-1.49])). Conclusions Medical programme and medical school are associated with MRCS success. Further research is needed to tease out the relationship between individual factors, medical school and MRCS performance.

  PublisherOA PDFDOI

• Characteristics, Outcomes, and Trends of Patients With COVID-19–Related Critical Illness at a Learning Health System in the United States

  Annals of Internal Medicine · 2021-01-18 · 122 citations

  articleOpen access

  BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to surge in the United States and globally. OBJECTIVE: To describe the epidemiology of COVID-19-related critical illness, including trends in outcomes and care delivery. DESIGN: Single-health system, multihospital retrospective cohort study. SETTING: 5 hospitals within the University of Pennsylvania Health System. PATIENTS: Adults with COVID-19-related critical illness who were admitted to an intensive care unit (ICU) with acute respiratory failure or shock during the initial surge of the pandemic. MEASUREMENTS: The primary exposure for outcomes and care delivery trend analyses was longitudinal time during the pandemic. The primary outcome was all-cause 28-day in-hospital mortality. Secondary outcomes were all-cause death at any time, receipt of mechanical ventilation (MV), and readmissions. RESULTS: Among 468 patients with COVID-19-related critical illness, 319 (68.2%) were treated with MV and 121 (25.9%) with vasopressors. Outcomes were notable for an all-cause 28-day in-hospital mortality rate of 29.9%, a median ICU stay of 8 days (interquartile range [IQR], 3 to 17 days), a median hospital stay of 13 days (IQR, 7 to 25 days), and an all-cause 30-day readmission rate (among nonhospice survivors) of 10.8%. Mortality decreased over time, from 43.5% (95% CI, 31.3% to 53.8%) to 19.2% (CI, 11.6% to 26.7%) between the first and last 15-day periods in the core adjusted model, whereas patient acuity and other factors did not change. LIMITATIONS: Single-health system study; use of, or highly dynamic trends in, other clinical interventions were not evaluated, nor were complications. CONCLUSION: Among patients with COVID-19-related critical illness admitted to ICUs of a learning health system in the United States, mortality seemed to decrease over time despite stable patient characteristics. Further studies are necessary to confirm this result and to investigate causal mechanisms. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality.

  PublisherOA PDFDOI

Recent grants

• NIH Grant U01AI030189

  NIH · $4.3M · 1995

• NIH Grant P01AI046393

  NIH · $4.2M · 2005

• NIH Grant N01AI025147

  NIH · $2.8M · 1997

• NIH Grant N01AI005074

  NIH · $1.9M · 1995

• NIH Grant R01AI035220

  NIH · $721k · 1999

Frequent coauthors

• Gurdyal S. Besra

  University of Birmingham

  59 shared

• John T. Belisle

  Colorado State University

  56 shared

• Jennifer S. Myers

  Drexel University

  54 shared

• Richard P. Shannon

  Duke University Health System

  49 shared

• Joshua P. Metlay

  Harvard University

  49 shared

• Lisa M. Bellini

  University of Pennsylvania

  49 shared

• John S. Spencer

  42 shared

• Delphi Chatterjee

  Colorado State University

  39 shared

Education

• Medical Student

  Mayo Clinic School of Medicine

  2023