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Member Information
Robert Gross, MD
Assistant Professor of Medicine and Epidemiology
Division of Infectious Diseases
Office Phone: 215-898-2437
Office Fax: 215-573-5315
Email: grossr@mail.med.upenn.edu
Website(s): http://www.uphs.upenn.edu/idd/13.html
Education: MD 1991, Cornell University Medical College
Keywords: HIV, antiretroviral therapy, adherence, outcomes, epidemiology
Research and/or Clinical Interests:
Studying the relation between adherence and outcomes, barriers to adherence, and conducting intervention studies to improve adherence to antiretroviral therapy.
Summary:
Dr. Gross' research primarily focuses on HIV treatment. He has been the PI of 3 cohort studies on adherence, a cross-sectional study of the relation between health literacy and adherence, a cohort study of outcomes of individuals with low-level HIV viral loads and the PI of 2 cohort studies of medication errors, one in inpatients and the other using a Medicaid database to study outpatients. In addition, he is the Vice-Chair of an international study of a modified directly observed therapy intervention to improve adherence to antiretroviral therapy. The observational adherence studies have all been designed to assess the relation between adherence to therapy and outcome and develop alternative methods of measuring adherence and ultimately on intervening to improve adherence. Two of the cohorts were designed to answer complementary questions about the nature of adherence to therapy, both using microelectronic monitors to measure adherence. The first cohort was begun in 1998 and continued through 1999 and included only individuals who were newly started highly active antiretroviral therapy in order to answer the question of the relation between adherence and virological suppression. We found a strong relation between adherence and virological outcome. An important finding was that adherence was not different during the first month of therapy between those ultimately having success and those later going on to fail, suggesting that adherence wanes after the first month of therapy. This work resulted was published in the journal AIDS . The second cohort study has not yet yielded results, however, is closed to accrual with approximately 120 on study or completed. This cohort will complement the first study in that this cohort includes individuals who have already had initial success with their treatment (i.e., having already achieved undetectable viral loads). This study will assess whether adherence lapses explain the reason for breakthrough of viral replication and subsequent development of resistant virus. If so, it will also explore the risk factors for having such lapses so as to determine where to target future interventions which may differ from those that should be offered to the group studied in the first cohort, those newly starting therapy. Based on the findings of these studies, Dr. Gross has designed an adherence intervention called Managed Problem Solving, based on Problem Solving Therapy for depression. This intervention is multifactorial, targeting memory problems, social supports, health beliefs, depression, substance abuse, medication side-effects and self-efficacy and is currently in pilot testing. In addition, he has studied the use of medication refill records as a measure of adherence and found them to be more strongly associated with virological response than self-reported adherence. This technique allows for the study of adherence both prospectively without interviewing subjects and retrospectively in settings where pharmacy refill data is captured. Future directions include further exploring the relation between adherence and HIV drug resistance and the impact these have on outcome.
Representative Publications:
Papasavvas E, Ortiz GM, Gross R , Sun J, Moore EC, Heymann JJ, Moonis M, Gallagher B, Shull J, Nixon DF, Kostman JR, and Montaner LJ. Boosting of HIV-1-specific Cellular Immune Responses in Chronically Infected Persons Following Treatment Interruption. J Infect Dis 2000;182:766-75
Gross R, Bilker WB, Friedman HM, Strom BL. Effect of Adherence to Newly Initiated Antiretroviral Therapy on Plasma Viral Load. AIDS 2001, 15:2109-2117
Gross R, Bilker WB, Friedman HM, Coyne JC, Strom BL. Provider Inaccuracy in Assessing Adherence and Outcomes with Newly Initiated Antiretroviral Therapy. AIDS 2002, 16:1835-1837
Papasavvas E, Sandberg JK, Rutstein R, Moore EC, Mackiewicz A, Thiell B, Pistilli M, June RR, Jordan KA, Gross R, Maino VC, Nixon DF, Montaner LJ. Presence of HIV-1 Specific CD4 and CD8 Cellular Immune Responses in Suppressed and Partially-Suppressed Pediatric Patients. J Infect Dis 2003 (in press)
