Adherence to Protease Inhibitor Therapy and Outcomes in Patients with HIV Infection [Paterson DL, et al Ann Intern Med 2000; 133: 21]: This is the published report of one of the most highly quoted studies in HIV research as a result of presentations at the 1999 ICAAC meeting in San Diego and the 1999 Retrovirus Conference in Chicago. Consecutive patients were enrolled if they were receiving a PI or beginning treatment with a PI-containing regimen at one of two centers in Pittsburgh and Omaha. Adherence was measured by MEMS, charts were reviewed, and virologic results were obtained at three-month intervals. Adherence was defined by the number of doses recorded by the MEMS Track Cap, virologic failure was defined as a HIV RNA level >400 copies/mL, and the follow-up averaged six months. Results are summarized in the following table:

Adherence to antiretroviral therapy and outcome in 81 patients
Adherence (% pills taken)	% virologic failure (VL >400/mL)
>95%	21.7%
90 - 94.9%	54.6%
80 - 89.9%	66.7%
70 - 79.9%	71.4%
<70%	82.1%

Comment: This very important publication dramatically demonstrates not only the importance of compliance, but the level of compliance required to achieve good outcomes. The authors note in the discussion that 80% is the usual threshold for good compliance to medications for chronic diseases, but here the favorable results suggest the necessity of a threshold of 95% or higher. As with prior reports, clinicians were poor predictors of adherence. It was also noted that about half of the patients who had compliance >95% reported symptoms they believed were side affects of the drugs indicating the capability of good compliance despite such side affects. posted 7/19/2000