People taking HIV treatment who have a low CD4 cell count are especially likely to achieve an undetectable viral if they attend their routine clinic appointments, research published in the online edition of the Journal of Acquired Immune Deficiency Syndromes suggests.
The US study showed that retention in HIV care had a stronger association with viral suppression for people with a low CD4 cell count than people with stronger immune systems.
Overall, people with higher CD4 cell counts were more likely to achieve an undetectable viral load. However, the effect of regular clinic attendance on the chances of viral suppression was greater for people with immune suppression.
“While it is well established that retention in care is important for all HIV-infected patients”, write the authors, “our data suggest that retention in care may be even more central to achieving optimal virologic outcomes for persons with advanced HIV disease.”
The study population consisted of 35,433 adults living with HIV who received care at 18 centres across the United States between 2006 and 2011. The investigators used three separate measures to define retention in care:
- Two or more outpatient visits separated by 90 or more days during a calendar year.
- A gap of less than six months between follow-up appointments.
- Attending clinic appointments every three months over the course of a calendar year.
Viral suppression was defined as a viral load below 400 copies/ml.
The patients were categorised according to their CD4 cell counts: below 200, 201-350, 351-500 and over 500 cells/mm3.
The investigators conducted a series of analyses to see which factors were associated with retention in care and viral suppression.
The proportion of people taking HIV therapy increased over the study period from 76 to 85% and median CD4 cell count at the time of entry to care increased from 399 to 476 cells/mm3.
Analysis of clinic attendance records showed that between 83 and 85% of patients had two or more clinic visits separated by at least 90 days in a calendar year; 75 to 78% did not have a 6-month gap between appointments; and 34 to 39% had clinic visits in all four calendar quarters.
Reflecting improvements in HIV treatment and care during the period of the study, the proportion of people achieving a viral load below 400 copies/ml increased from 60% in 2006 to 79% in 2011.
Regardless of retention measure, it was clear that the higher the initial CD4 cell count, the greater the probability of viral suppression. It was also apparent that at all CD4 cell counts, people who were retained in care were more likely to achieve an undetectable viral load than people who did not attend their regular clinic appointments. It was also notable that the effect of retention in care on viral suppression was greater at lower compared to higher CD4 cell counts.
The investigators explored this final point in greater detail. They found that the association between retention in care and viral suppression was strongest for people with a CD4 cell count below 200 cells/mm3 (AOR = 2.33, 95% CI, 2.16-2.51). The association diminished as CD4 cell count increased (201-350 cells/mm3, AOR = 1.96, 95% CI, 1.81-2.12; CD4 cell count 351-500 cells/mm3, AOR = 1.65, 95% CI, 1.53-1.78; CD4 cell count above 500 cells/mm3, AOR = 1.22, 95% CI, 1.14-1.30).
“Retention in care is more strongly associated with viral suppression in patients with low CD4 counts,” comment the authors.
They note that people with low CD4 cell counts have an increased risk of opportunistic infections, HIV-related complications, are often taking multiple therapies and may also be living with social problems. “Maintaining a continuous, high-quality, relationship with a provider may help patients with advanced HIV disease manage these issues, and may explain why viral suppression is more strongly associated with retention in care in this population compared to individuals with higher CD4 cell counts,” suggest the authors.
They conclude: “Our findings have important implications for improving the health of patients with advanced HIV disease and emphasize the role of retention in care in test-and-treat approaches to HIV prevention, demonstrating the added value of retaining people with lower CD4 counts in care.”
Yehia BR et al. Retention in care is more strongly associated with viral suppression in HIV-infected patients with lower versus higher CD4 counts. J Acquir Immune Defic Syndr, online edition. DOI: 10.1097/000000000000023, 2013.