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Michael Horberg

Michael Horberg, MD, MAS, FACP, FIDSA

Associate Medical Director of Research, Medical Education, Community Health, Medicaid, Genetics, HIV & STI, Transgender Health, Complex Care Program, Infection Prevention

Executive Director, Mid-Atlantic Permanente Research Institute
Director HIV/AIDS and STI, Kaiser Permanente and Care Management Institute


MAS, University of California, San Francisco
Residency, Categorical Internal Medicine, Michael Reese Hospital/University of Chicago
MD, Boston University School of Medicine
BA, Boston University

Academic Affiliations:

Professor of Medicine, Kaiser Permanente School of Medicine

Professional Affiliations:

Past Chair, Kaiser Permanente National Research Council
Chair, AHIP/CMS HIV and Hepatitis C Quality Measures Working Group
Co-chair, IDSA/HIVMA HIV Primary Care Guideline Committee
Incoming Chair, Health Care Systems Research Network
Past Chair, HIV Medicine Association
Past President, Gay and Lesbian Medical Association
Fellow, American College of Physicians
Fellow, Infectious Disease Society of America (IDSA)
Member, AcademyHealth

Michael Alan Horberg, MD, MAS, FACP, FIDSA is Associate Medical Director for Kaiser Permanente Mid-Atlantic Permanente Medical Group (KPMAS MAPMG), serving greater Baltimore and District of Columbia, suburban Maryland and northern Virginia.  In that role, he is responsible for Research, Medical Education, Community Health, Medicaid, Genomics, HIV and STI, Complex Care, LGBTQI+ Health and Infection Prevention.

Dr. Horberg is the director of HIV/AIDS nationally for KP, serving nearly 80,000 members with HIV, as well as Clinical Lead for HIV/AIDS and STI, creating clinical multidisciplinary guidelines to improve such care in KP. He has chaired the KP HIV, Liver Disease, STI, and LGBTQ Health Conference since 2003, bringing together clinical and research staff to ensure best practices.

Under President Obama, Dr. Horberg served on the Presidential Advisory Council on HIV/AIDS (PACHA), and co-chaired the Access to Care and Improved Outcomes Committee.  Dr. Horberg is a Fellow of the American College of Physicians and the Infectious Disease Society of America (IDSA).  He is Past-Chair of the Board of Directors of the HIV Medicine Association (HIVMA).  He has served on the IDSA Quality Performance Committee, and presently co-chairs the HIVMA/IDSA HIV Primary Care Guideline Committee. Dr. Horberg presently serves as the physician chair of the CDC-sponsored Health Care Action Group, promoting sexual health. He has chaired multiple Expert Panels on HIV-related provider performance measures (including ones sponsored by CMS, NCQA, and IDSA), and has served on NIH and CDC peer-review panels. He is past-president of the national Gay and Lesbian Medicine Association.

Dr. Horberg leads HIV, STI, and Infection Prevention for MAPMG. He directs LGBTQI+ care and led creation of Pride Medical and Gender Pathways clinics within KPMAS. In his role as medical director for KPMAS Community Health and chief medical officer for KPMAS Maryland and Virginia Medicaid, he works to improve health equity and care access for underserved populations in the region.

As Executive Director for research, he is responsible for all research in KPMAS.  In this role, he leads a department of clinical and data research with over seventy employees.  His HIV research interests are HIV quality measures, care improvement, and determinants of optimized multidisciplinary care for HIV-infected patients. He studies epidemiology of HIV, hepatitis, sexually transmitted and COVID infections, leading all hepatitis care programs and COVID efforts in KPMAS.  Dr. Horberg has published over 200 manuscripts and delivered over 100 presentations at scientific meetings (all peer-reviewed).

As Director for Medical Education, he is the Designated Institutional Official for KPMAS, with responsibility for all undergraduate, graduate, and continuing medical education. He also leads the KPMAS Medical Genetics and Genomics strategy, and is Executive Sponsor for Commission on Cancer Accreditation and National Surgical Quality Improvement Program.

Dr. Horberg attended Boston University Medical School, and received his Master of Advanced Studies from University of California San Francisco.  He completed his residency in internal medicine at University of Chicago Michael Reese Hospital and Medical Center. He is a resident of Maryland, with his husband Chip and their pet poodle Grant.

Research Interests:

  • Models of Care
  • HIV Care and Outcomes Quality Metrics
  • Registry Development
  • Pharmaceutical Safety and Comparative Effectiveness
Sexually Transmitted Infection:
  • Gay/Lesbian Health and STI risk
  • Syphilis
  • Registry Development
  • Hepatitis Care Quality Metrics

For a full list of publications, please see Dr. Horberg’s Curriculum Vitae.

    1. Lang R, Hogan B, Zhu J, McArthur K, Lee J, Zandi P, Nestadt P, Silverberg MJ, Parcesepe AM, Cook JA, Gill MJ, Grelotti D, Closson K, Lima VD, Goulet J, Horberg MA, Gebo KA, Camoens RM, Rebeiro PF, Nijhawan AE, McGinnis K, Eron J, Althoff KN; North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) of the International Epidemiologic Databases to Evaluate AIDS (IeDEA), “The Prevalence of Mental Health Disorders in People with HIV and the Effects on the HIV Care Continuum,” AIDS, 2023; 2023 Feb 1;37(2):259-269.
    2. Zalla LC, Cole SR, Eron JJ, Adimora AA, Vines AI, Althoff KN, Silverberg MJ, Horberg MA, Marconi VC, Coburn SB, Lang R, Williams EC, Gill MJ, Gebo KA, Klein M, Sterling TR, Rebeiro PF, Mayor AM, Moore RD, Edwards JK, “ Association of Race and Ethnicity with Initial Prescription of Antiretroviral Therapy Among People with HIV in the US,” JAMA. 2023; 2023 Jan 3;329(1):52-62.
    3. Jaurretche M, Byrne M, Happ LP, Levy M, Horberg M, Greenberg A, Castel AD, Monroe AK; DC Cohort Executive Committee, “HIV Care Continuum Outcomes among Recently Diagnosed People with HIV (PWH) in Washington, DC,” Epidemiol Infect. 2023; 2023 Jan 30;151:e45.
    4. Jetsupphasuk M, Hudgens M, Lu H, Cole S, Edwards J, Adimora A, Althoff K, Silverberg M, Rebeiro P, Lima V, Marconi V, Sterling T, Horberg M, Gill MJ, Kitahata M, Moore D, Lang R, Gebo K, Rabkin C, Eron J, “Optimizing Treatment for Human Immunodeficiency Virus to Improve Clinical Outcomes Using Precision Medicine,” American Journal of Epidemiology, 2023; 2023 Mar15: kwad057.
    5. Burrell T, Kim S, Mohadikar K, Jonas C, Ortiz N, Horberg M, “Family Structure and Adolescent Mental Health Service utilization During COVID-19 Pandemic,” Journal Adolescent Health, 2023; 2023 April 7: S1054-139X(23)00065-4.
    6. Lang R, Humes E, Coburn S, Horberg M, Fathi L, Watson E, Jefferson C, Park L, Justice A, Gordon K, Napravnik S, Edward J, Browne L, Silverberg M, Skarbinski J, Leyden W, Stewart C, Hogan B, Gebo K, Williams C, Althoff K, for the Corona-Infectious-Virus Epidemiology Team (CIVETs) of the NA-ACCORD of IeDEA, “Analysis of severe illness after SARS-CoV-2 breakthrough infection in people with and without HIV in the United States,” JAMA Network Open, 2022; 2022 Oct 3;5(10):e2236397.
    7. Lea A, Leyden W, Sofrygin O, Marafino B, Skarbinski J, Napravnik S, Agil D, Augenbraun M, Benning L, Horberg M, Jefferson C, Marconi V, Park L, Gordon K, Bastarache L, Gangireddy S, Althoff K, Coburn S, Gebo K, Lang R, Willsiams C, Silverberg M, “HIV Status, Tenofovir Exposure, and the Risk of Poor COVID-19 Outcomes: Real World Analysis from 6 United States Cohorts Prior to Vaccine Rollout,” Clinical Infectious Diseases, 2023; 2023 Mar 2;ciad084; online ahead of print.
    8. Miller M, Eberhart L, Jefferson C, Horberg M, “Beyond Antiretroviral Treatment: Patterns and Factors Associated with Composite Medication Adherence Before and During the COVID-19 Pandemic in Patients with HIV with Multiple Chronic Conditions,” JAIDS, 2023; 2023 Apr 15;92(5):405-413.
    9. Jefferson C, Watson E, Certa J, Gordon K, Park L, D’Souza G, Benning L, Abraham A, Agil D, Napravnik S, Sivlerberg M, Leyden W, Skarbinski J, Williams C, Althoff K, Horberg M, “Differences in COVID-19 Testing and Adverse Outcomes by Race, Ethnicity, Sex, and Health System Setting in a Large Diverse US Cohort,” PLOS One, 2022 Nov 23;17(11):e0276742.
    10. Byrne M, Akselrod H, Monroe A, Horberg M, Lucar J, Castel A, Denyer R, Doshi R, Secco A, Squires L, Schrofter S, Benator D, on behalf of the DC Cohort Executive Committee, “Identifying geographic areas of Washington DC with increased potential for sexual HIV transmission among People with HIV with STIs and concurrent elevated HIV RNA: Data from the DC Cohort,” Open Forum Infectious Diseases, 2022; Mar 18;9(5):ofac139.
    11. Avula H, Ambrosy A, Silverberg M, Reynolds K, Towner W, Hechter R, Horberg M, Vupputuri S, Leong T, Leyden W, Harrison T, Lee K, Sung SH, Go A, “Human Immunodeficiency Virus Infection and Risks of Morbidity and Death in Adults with Incident Heart Failure,” European Heart Journal (Open), 2021 Dec 1;1(3):oeab040.
    12. Lang R, Gill MJ, Coburn S, Grossman J, Gebo K, Horberg M, Mayor A, Sivlerberg M, Willig A, Justice A, Klein M, Bosch R, Rabkin C, Hogan B, Thorne J, Moore R, Althoff K, for the North American AIDS Cohort Collaboration on Research Design (NA-ACCORD) of the International Epidemiologic Databases to Evaluate AIDS (IeDEA), “The Changing Prevalence of Anemia and Risk Factors in People with HIV in North America Who Have Initiated ART, 2007-2017,” AIDS, 2022; e-pub ahead of print.
    13. Muiru A, Madden E, Scherzer R, Horberg M, Sivlerberg M, Klein M, Mayor A, Gill MJ, Napravnik S, Crane H, Marconi V, Koethe J, Abraham A, Althoff K, Lucas G, Moore R, Shlipak M, Estrella M, “Effect of Adopting the New Race-Free 2021 Chronic Kidney Disease Epidemiology Collaboration Estimated Glomerular Filtration Rate Creatinine Equation on Racial Differences in Kidney Diesase Progressio among People with Human Immunodeficiency Virus: An Observational Study,” Clinical Infecitous Diseases, 2022; e-pub ahead of print.
    14. Lam O, Leyden W, Leong T, Horberg M, Reynolds K, Ambrosy A, Avula H, Hechter R, Towner, W, Vupputuri S, Go A, Silverberg M, “Variation in Heart Failure Risk by HIV Severity and Sex in People with HIV Infection,” JAIDS, 2022; 92(2): 175-181.


    1. Vaccine Safety Datalink (VSD) Project
      Goal: KPMAS has joined the VSD as the site for Mid-Atlantic. We will explore and report on vaccine safety and provide regular data updates for assigned projects and for advanced signals for new and established vaccinations. This is performed for all communities and age groups.
      Funder: CDC
      Role: Principal Investigator
    2. Kaiser PrEP Data
      Goal: This will provide additional data and demographics to assess the United States’ use of HIV Pre-Exposure Prophylaxis and study the demographics and opportunities for its use within the USA.
      Funder: US Center for Disease Control
      Site Principal Investigator
    3. North American AIDS Cohorts Collaboration on Research and Design (NA-ACCORD). Administrative Supplement: Investigating PASC in integrated and non-integrated systems
      Goal: The purpose of the study is to compare PASC (Post Acute Sequelae of CoV-2-SARS)with accounting for pre-existing conditions and matching to the COVID-negative population, comparing by HIV antibody status.  Comparisons to another health system (Johns Hopkins Medicine) and by COVID vaccination status also will be studied. The initial investigation resulted in showing an increased risk of PASC among patients with COVID-19 but also helped define the syndrome.
      Funder: National Institute of Allergy and Infectious Diseases
      Role: Principal Investigator
    4. Assessing Syndemics of Cardiovascular Disease in People with and without HIV
      Goal: This study will explore the role of social demographic and community factors in the impact of HIV on heart disease and vice versa. It also will explore the use of KP Research Bank for data and blood samples to explore the role of genetics in these morbidities.
      Funder: National Heart, Lung, and Blood Institute
      Role: Co-investigator
    5. Cabotegravir PrEP: Actionable Robust Evidence for Translation into Practice (CABARET)
      Goal: This study will explore what factors contribute to the employment of long-acting HIV Pre-Exposure Prophylaxis and how can this best be encouraged and grown in use to prevent HIV infection within an integrated care system.
      Funder: National Institutes of Mental Health
      Role: Co-investigator
    6. Genome-Wide Association Study of Bloodstream Infection Incidence and Mortality in the General Population
      Goal: This study explores the possibility of multiple gene mutations (both single and multiple) that could lead to an increased risk of bloodstream infections and the possibility of mortality. Dr. Horberg will oversee the use of the KP Research Bank data for the study.
      Funder: Norwegian University Science Technology
      Role: KP Principal Investigator
    7. The DC Cohort: A Longitudinal Poputalion-Based Cohort of People Living With HIV in Washington DC.
      Goal: The goals of this study are 1) enhance the Cohort database to incorporate new data sources to comprehensively describe and monitor HIV and co-occurring conditions; 2) expand the use of the existing DC Cohort Clinical Dashboard to monitor HIV care outcomes as well as key indicators related to ending the HIV epidemic; and 3) use the Cohort as a platform from which to develop pioneering interventions to improve the quality of care of people living with HIV.
      Funder: National Institute of Allergy and Infectious Disease, George Washington University
      Role: Co-Investigator and Site Principal Investigator
    8. Kaiser Permanente Research Bank
      Goal: In this study, KP Research Bank aims to recruit 280K members total across all KP regions to increase the overall Research Bank collection to 500K. Members will be consented to provide a biospecimen and complete a survey. This region will participate in the recruitment and other Research Bank-related efforts, including scientific, strategic and operational.
      Funder: Kaiser Permanente Research Bank
      Role: Principal Investigator and Site Principal Investigator
    9. North American AIDS Cohorts Collaboration on Research and Design (NA-ACCORD)
      This is the North American response to IeDEA, and for which KP Northern California and Mid-Atlantic States participate. It is a collaborative cohort compendium and analysis for the purpose of achieving sufficient power to address issues that could not be adequately addressed by single cohorts.
      National Institute of Allergy and Infectious Diseases
      Site Principal Investigator and member of the Executive Committee
    10. COMpAAAS Tripartite: ART-CC, KP, and VA
      Goal: The purpose of the overall study is to participate in a scientific collaboration across three grant partners to assemble data sets, including electronic health record data.  Partners will interpret and disseminate the results of the study through conference abstracts and manuscripts.
      Funder: National Institute of Health
      Role: Site Principal Investigator

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