July 1, 1998
This study looked at the prevalence of PI use (in combination with nukes), the level of viral suppression after use of PIs, subsequent resistance, and adherence to PI therapy. The study enrolled 153 economically disadvantaged HIV+ patients, recruited from San Francisco homeless shelters, free food lunch lines, and single room occupancy (SRO) hotels that cost under $400 a month. Bangsberg and colleagues measured baseline antiretroviral regimens, viral load after 1-3 months on therapy, proportion of patients who reached undetectable at 3-9 months, and any viral resistance.
Perhaps the most significant finding of this study is that after 20 months, the patients had attended 91% of all scheduled clinic visits. This contradicts the general bias -- held by many -- that poor people tend to be unreliable in keeping doctors' appointments.
PI use in the cohort rose dramatically over the study period. During July-September 1996, 3% of patients were on a protease-containing regimen; by January-March 1998 that number had risen to 26%. However, the total percentage of patients on any type of antiretroviral therapy never reached 50%.
Among patients on PIs, the mean viral load reduction after three months of therapy was 1.2 log. Only 30-40% of patients became undetectable in the 3-9 month follow-up period. This is generally a lower percentage than one would predict. This anomaly, according to the researchers, cannot be attributed solely to the emergence of viral resistance, since the resistance testing performed indicated that common mutations generally were not present in these patients.