HIV Patients May Be Over-Monitored

Less frequent monitoring of patients with virally suppressed human immunodeficiency virus (HIV) and a CD4 count higher than 200 cells per μL does not worsen outcomes for these patients, according to a recent study. However, more frequent monitoring may help reduce the risk of virological failure.

In this observational study, the researchers obtained and evaluated data from the HIV-CAUSAL Collaboration and the Centers for AIDS Research Network of Integrated Clinical Systems. The researchers included in their analysis prospective studies of 47,635 HIV-positive patients who had initiated antiretroviral therapy between January 1, 2000, to January 9, 2015, in 9 countries.
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The researchers compared 3 monitoring strategies that have different thresholds to measure CD4 cell count, and HIV RNA viral loads every 3 to 6 months when below the threshold or every 9 to 12 months when above the threshold. The strategies included in the study had threshold CD4 counts of 200 cells per μL, 350 cells per μL, and 500 cells per μL.

Additionally, hazard ratios (HRs) of death and of AIDS-defining illness or death, risk ratios of virological failure, and mean differences in CD4 cell count were estimated via inverse probability weighting to adjust for baseline and time-varying confounders.

During follow-up, CD4 cell count was measured every 4 months, on average, and viral load was measured every 3.8 months. A total of 464 participants had died (107 in threshold 200 strategy, 157 in threshold 350, and 200 in threshold 500), and 1091 participants either demonstrated AIDS-defining illnesses or had died (267 in threshold 200 strategy, 365 in threshold 350, and 459 in threshold 500).

Compared with threshold 500, the mortality HR was 1.05 for threshold 200 and 1.02 for threshold 350. The researchers determined the corresponding estimates for AIDS-defining illness or death to be 1.08 for threshold 200 and 1.03 for threshold 350. The 24-month risk ratios of virological failure (viral load more than 200 copies per mL) were 2.01 for threshold 200 and 1.24 for threshold 350, vs threshold 500. Mean CD4 cell count differences at 24 months were 0.4 cells per μL for threshold 200 and −3.5 cells per μL for threshold 350.

“Decreasing monitoring to annually when CD4 count is higher than 200 cells per μL compared with higher than 500 cells per μL does not worsen the short-term clinical and immunological outcomes of virally suppressed HIV-positive individuals,” the researchers concluded. “However, more frequent virological monitoring might be necessary to reduce the risk of virological failure. Further follow-up studies are needed to establish the long-term safety of these strategies.”

–Christina Vogt

Reference:

Caniglia EC, Cain LE, Sabin CA, et al; HIV-CAUSAL Collaboration the Centers for AIDS Research Network of Integrated Clinical Systems. Comparison of dynamic monitoring strategies based on CD4 cell counts in virally suppressed, HIV-positive individuals on combination antiretroviral therapy in high-income countries: a prospective, observational study. Lancet HIV. 2017;4(6):e251-e259. doi:10.1016/S2352-3018(17)30043-7.