Medication Adherence: The Final Frontier

Treatment of HIV has become so amazingly effective that when it fails, it's no overstatement to say that it's usually because the patient is not taking the medications. There are all kinds of provider-related reasons for this -- inadequate patient education, prescribing and dispensing errors, failure to address language or education deficits -- but here I want to focus on the patient-related causes.

In other words, on non-adherence.

(This used to be called "non-compliance." That term has become un-PC; for some reason non-adherence is viewed as nicer. Please explain.)

Non-adherence in HIV care comes in a variety of flavors, including:

1. Denial -- "I feel fine, so why should I take those medicines? Yes, you tell me I have HIV, but I don't really believe it's a dangerous condition, or even that I have it, since as I said, I feel fine."
2. Stigma -- "I won't take those medications because each dose reminds me that I have HIV. And that makes me feel awful again and again, so until we can solve that problem, no chance I'm taking HIV meds."
3. Chaos -- "You say I should take these medications, but how can I do so when my life is so horribly complicated because of family issues [or addiction or other medical problems or homelessness or ...], so I'm going to ignore that recommendation to go on meds, and take my chances."
4. Deceit -- "I'm taking the medications exactly as you prescribed. I rarely, if ever, miss a dose. Yes, my pharmacy told you I have not refilled my one-month supply of meds since 2009, but that doesn't change the fact that I'm taking the medications exactly as prescribed. I told you that already."
5. Hypersensitivity -- "I get side effects to everything. Literally everything. So I might leave the office today with a prescription, but I won't fill it, because it will make me sick. Look, when I told you this, and you said that all medicines might have side effects, you proved my point."
6. Sicko -- "Sure, I'll take the medications if insurance covers the cost. But I lost my insurance, so rather than investigate getting on COBRA or an AIDS Drug Assistance Plan (ADAP) or some other program to keep me covered, I just stopped my meds. And that was 6 months ago."

I'm sure there are others, but this list covers most of them. Note that these are not mutually exclusive, and some of the knottiest adherence problems come when more than one of the above is operative. Note also that I'm not counting the people who simply disappear from care -- the "engagement in care" or "linkage" issue -- which is a huge problem and responsible for lots of the drop-off in the infamous treatment cascade.

But the multifactorial nature of poor adherence is one reason why studies of adherence interventions so often have negative results. How can any single intervention address all of these factors?

Another reason for the negative studies is that the vast majority of patients do take their antivirals correctly -- and this good med-taking behavior is probably especially common among those with the wherewithal to sign an informed consent for a clinical study. Most of these folks don't need any help at all, so the intervention looks no better than the control; this study is an excellent example.

Yet if we can't identify ahead of time the small fraction of our patients who will be non-adherent -- and study after study says we can't -- how can we target our interventions to the people who need them the most?

(Next up: An Adherence Intervention that Actually Works -- But There's a Catch)

Paul Sax is Clinical Director of Infectious Diseases at Brigham and Women's Hospital. His blog HIV and ID Observations is part of Journal Watch, where he is Editor-in-Chief of Journal Watch AIDS Clinical Care.