HIV: When to Treat?

Well, I'm finally home in Saginaw and I just wanted to write a concluding post for this elective on an important topic that is the subject of continual debate in the field of HIV medicine -- when should HIV-positive patients begin HAART (highly active antiretroviral therapy)?


As a novice in my experience with HIV medicine, I had initially assumed that it was something that everyone got started on as soon as they received the diagnosis.  But that is not necessarily the case.  According to the current guidelines, the Health & Human Services Panel on Antiretroviral Guidelines makes most determinations on the need for therapy based on CD4 T-cell count.  This is one of the key lab values followed over time as it can drop dangerously low (CD4 count threshold for AIDS is 200).  The panel is definitely unanimous on one guideline:

Initiate HAART in all HIV-positive patients with a CD4 count below 350.


There is strong data from randomized controlled trials that supports this recommendation.

Now, where it gets dicey is when we are making decisions about patients with CD4 counts above 350.  There is promising evidence from nonrandomized and observational cohort studies that there is benefit to treating patients even with higher CD4 counts.  The evidence suggests that treating patients in the 350-500 CD4 range can help prevent the progression of HIV-related illness (inflammatory processes from viral infection can have effects on several organ systems, including cardiovascular/kidney/liver disease and even malignancies).  However, it is unclear whether this truly impacts mortality outcomes.  And in general, there isn't a convincing amount of data at this point that has shown a strong patient benefit of initiating therapy at CD4 levels above 500.

These studies were focused on considerations of the effects of therapy on individual patients' health status, but what about the public health perspective?  There has been an emerging body of experts in the field who champion HIV therapy as a strategy for prevention.  That is, by treating all HIV-positive patients, we are not only maximizing patients' T-cell counts but also keeping viral load levels down and decreasing individuals' transmissibility of the virus.  It's win-win!  We are keeping currently infected individuals healthier and also helping to prevent others from getting infected.  It seems obvious.  So why isn't everyone on therapy?

Well, we don't live in a perfect world and there are several factors to take into account when starting an individual on HAART.  First of all, any medication has its potential for side effects, and there is a long list of what one might expect, from GI upset to lipodystrophy (fat wasting and redistribution, which can be quite alarming to patients).  Also, adherence to therapy is a strong consideration-- if a patient is unlikely to reliably take his/her meds due to homelessness, lack of understanding, mental health issues, etc., it can actually be detrimental to start therapy, as there is risk of creating resistant viral strains if doses are missed or therapy is discontinued.

The clinician has to take all of these factors into consideration when making a decision about whether to start therapy in a patient with a CD4 count >350.  If a patient is clearly very motivated, with a strong support system, an understanding of the risks/benefits/alternatives of therapy, and a commitment to taking this medicine for a lifetime, then there is no reason not to initiate treatment.  But the onus is on the physician to educate, advise, and discuss all of these issues to assist the patient in making an appropriate decision.  And hopefully, with new initiatives on the horizon such as pre-exposure prophylaxis for high-risk individuals, HIV-positive individuals and their partners will have more options to determine what is the best approach for them.