For Our Stable HIV Patients, Why Are We Still Sending All These Lab Tests So Often?

Interesting query from a colleague recently:

I'm a community ID doc in the trenches (the measles trenches at present) with an HIV question. Why do we still check CBCs & chem panels every 3-6 months in our HIV patients? Particularly our well-controlled, virologically-suppressed patients? This strikes me as a tremendous waste. I haven't been in practice that long, but I can count on one hand the number of times these routine labs have led to a change in ART (and even then, it was probably a patient on TDF, which I don't use much any more). Is this an evidence-based practice? Or a vestige of an earlier era of more toxic drugs?

Andrew raises an important question -- do the guidelines for laboratory monitoring still make sense when our HIV treatments have become so safe and effective?

Below I've summarized the labs recommended by the DHHS Guidelines for our stable patients -- the people who have been virally suppressed on ART for years. In italics, a bit of commentary.

  • CD4 cell count -- if CD4 < 300, every 3-6 months; if CD4 300-500, every 12 months; if > 500, optional. Wow, that's complicated. How about never? One could easily argue that CD4 monitoring is only needed in those very rare patients who have persistently low CD4 (e.g., < 200) despite long-term viral suppression. Remember, HIV treatment should not be changed based on CD4 results alone.
  • HIV RNA (viral load) -- every 6 months. While the viral load is absolutely critical for monitoring adherence, does a strategy of twice-yearly measurement make sense for patients who have been on effective treatment for a gazillion years, are on a perfectly good regimen, and have never failed therapy?
  • Basic chemistries, LFTs, and CBC (when measuring CD4) -- every 6 months. This was the group of tests alluded to by Andrew in the above email, and I agree that they rarely pick up something of HIV- or ART-related concern with current treatments. Exceptions would be for patients with known comorbidities -- but this is a different indication for testing. About the only good thing you can say about this testing is that it's cheap, at least compared to CD4s and viral loads.
  • Urinalysis -- yearly if on TAF or TDF. Certainly this makes sense with TDF, and again also when there are concomitant risk factors for renal disease (diabetes, hypertension). But in an otherwise healthy young person not on a TDF-based regimen? The incidence of clinically important abnormalities with this yearly screen must be extraordinarily low.

Here, then, is a revised (and deliberately provocative) recommendation for monitoring the otherwise healthy people (who happen to have HIV), and who have long-term viral suppression -- let's say at least 5 years < 200, just to be safe. Let's also assume they are also currently receiving a recommended regimen that does not include TDF:

  • HIV RNA (viral load) -- yearly.
  • CD4 cell count -- never.
  • All other tests (chemistries, renal function, LFTs, CBC, urinalysis) -- at comparable age-appropriate or comorbidity-appropriate frequency to HIV-negative people.

When I've floated this idea by certain colleagues, they frequently cite the asymptomatic sexually transmitted infections they've picked up in their twice-yearly (or more frequent) monitoring.

I'd argue that this reflects an individual's STI risk, which is not the same in all people with HIV. By all means, continue to screen for STIs when clinically indicated, and the same goes for underlying medical problems that increasingly arise during aging.

So to test this revised strategy, let's imagine a clinical study:

Eligible: Stable on guidelines-approved ART; no history of virologic failure or treatment interruption; HIV < 200 on all measurements during the past 5 years.
Intervention: Randomized to 1) guidelines-recommended monitoring, or 2) HIV RNA once-yearly, other testing as indicated by demographics, clinical status, comorbid conditions, STI risk.
Primary endpoint: Virologic suppression at the end of the study.
Secondary endpoints: Occurrence/diagnosis of HIV or non-HIV-related comorbidities; cost (to healthcare system); cost (to patient).

And, since we're talking about a way to reduce office visits and healthcare utilization, how about this recent "appointment" in Alaska?