In an article published online ahead of print in Clinical Infectious Diseases, results from the large COHERE study show that HIV-positive people with 500-750 CD4s have a higher rate of AIDS-defining illnesses (ADI), compared to those with CD4s above 750 cells. Although the comparison is statistically significant, the risk of an ADI is still rather low in this range.
Much research points to the advantages of starting HIV treatment before CD4 counts fall below 500. There is significant risk of ADIs when CD4 counts are below 350, and especially so for those with 200 or fewer CD4s. Some evidence shows a similar risk of ADIs for people with 350–500 CD4s, although at a lower level of risk.
Researchers looked at risk for ADIs over a range of CD4s, and compared ranges of <200, 200–349, 350–499, 500–749, 750–999 and >1,000. From 1998–2010, more than 200,000 people 14 years or older were included with at least one CD4 count of 200 or higher.
A total of 12,135 new ADIs occurred in people with >200 CD4s over the course of the study. About 3/4 of these ADIs occurred at CD4 counts below 500. The rate of ADIs for the 200–349 range was 20.5 cases/1,000 person years, while the rate was 10.2 cases for 350–499, 6.4 cases for 500–749, 4.7 cases for 750–999 and 4.1 cases for >1,000 CD4s. Having a CD4 count above 1,000 offered no statistically lower risk of ADIs over the lower 750–999 range.
The most common ADIs included esophageal candidiasis (13%), Kaposi Sarcoma (11%) and pulmonary tuberculosis (10%). Others included Mycobacterium avium complex and recurrent herpes infections.
These and other data continue to point to the advantages of starting HIV treatment earlier, in order to preserve immune function and reduce risks for developing co-morbid conditions over time. For a more detailed analysis, read HIVandHepatitis.com’s coverage.
RESEARCH:
A Mocroft, et al (COHERE study). Incidence of AIDS-Defining Illnesses at Current CD4 Count >200 Cells/µL in the Post-Combination Antiretroviral Therapy Era. Clinical Infectious Diseases. August 6, 2013 (ahead of print online).