• Does it Matter Where You Came From? Prognosis of Patients Starting Potent Therapy, According to Initial Response (Oral 181)
  Authored by J.A.C. Sterne, M. May, D. Costagliola, P. Pezzotti, B. Ledergerber, F. de Wolf, J. Lundgren, J.S. Fusco, S. Staszewski, F. Raffi, R.S. Hogg, A.N. Phillips, M.J. Gill, G. Fatkenheuer, G. Chene
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The ART Cohort Collaboration, a consortium of 13 cohorts in Europe and North America that includes over 12,500 treatment-naive patients, evaluated the question of what the most important prognostic factors are after starting HAART. Prior studies (Eggers M et al, Lancet 2002) had demonstrated that baseline CD4 cell count was a more powerful predictor of clinical outcome than baseline viral load among patients initiating HAART. Since dramatic changes in both CD4 cell counts and HIV viral load can occur within a few months of starting potent combination antiretroviral-naive patients (representing 13,408 patient-years of follow-up) to see if initial CD4 cell and viral load responses to therapy might be more useful in predicting disease progression than baseline status.

Patients were included if they had at least one CD4 cell count and viral load determination from six to nine months (subsequently called the "six month" result for simplicity) after starting HAART, in addition to baseline (pre-treatment) values. The investigators looked for associations between overall survival and AIDS-free survival taking baseline and six month CD4 cell counts and viral loads into account. Neither baseline CD4 cell count, baseline viral load nor the change from baseline values to six months were predictive of clinical outcome after controlling for the six-month values. However, the six-month values were strongly associated with both overall and AIDS-free survival. Acquisition of HIV through injection drug use, age >50 years, and the occurrence of an AIDS-defining event before or zero to six months after starting HAART, were also strongly predictive.

The investigators have developed a prognostic model available to clinicians and patients alike to be used as a risk calculator. The model includes 288 different strata, and will be available at: www.art-cohort-collaboration.org. They are working on a similar model for cohorts based in developing countries.

So, in prognostic terms, it appears that it matters more where you are at six months than where you start from. Because important interactions between CD4 cell counts and HIV viral load have been demonstrated in a number of studies, it will be interesting to see what these investigators will find when the CD4 cell and viral load outcomes at the next measured time interval are subsequently compared to the data obtained at six months.