The HIV Outpatient Study (HOPS)

Northwestern University Subcontract Principal Investigator: Joan S. Chmiel, PhD

The HIV Outpatient Study (HOPS) is one of longest standing, and most clinically comprehensive cohort studies of HIV-infected persons receiving care in the United States.  Since 1993, the HOPS has collected data on over 8,400 HIV-infected patients seen at more than 300,000 outpatient visits during 32,000 person-years of observation in 9 medical practices specializing in the treatment of HIV infection. In 2008, there were approximately 2,400 persons who were considered active enrollees in the HOPS (i.e. attended at least two HIV-related care visits) of whom approximately 1,800 (75%) had been followed continuously for >3 years.  Comprehensive routine medical information (e.g., symptoms, medication names and dosing, laboratory values, and diagnoses) as well as event-driven data are collected at the time of clinical encounter by medically trained abstractors working in the care providers’ practices using standardized electronic formats; there are no paper forms.  Data are reviewed and edited monthly with closeout and dissemination quarterly.   

The HOPS is recognized particularly for its depth of data collection, its flexibility, and the rapidity with which data are reported. These qualities permit two strategic activities: i) recognition and reporting of significant new trends affecting HIV-infected persons in care in a near real-time, sentinel fashion and ii) analysis of longitudinal multi-year data concerning a uniquely wide range of treatment practices and preventable secondary risks. Many of the early and important observations that have substantially impacted secondary prevention and control of HIV disease were first reported from HOPS with later corroboration by other groups. Numerous HOPS manuscripts have been high-profile articles in widely read journals. As it has since inception, the HOPS remains strategically poised to address critical questions related to the treatment and care of HIV-infected persons. 

The HOPS is a dynamic cohort; enrollees leaving the study are actively replaced by new enrollees to maintain a minimum total active cohort size and maximize follow-up time per enrollee.  This practice has also permitted the HOPS to evolve in parallel with the national HIV epidemic, as reflected by the changing demography of enrollees, which remains more representative of HIV-infected Americans than other comparable national studies. 

The HOPS is funded by the Centers for Disease Control and Prevention (CDC).  Dr. Chmiel provides biostatistical support for the HOPS.