The majority of patients newly diagnosed with HIV in North America have a CD4 cell count that is low enough to warrant the immediate initiation of antiretroviral therapy, investigators report in the June 1st edition of Clinical Infectious Diseases.
Until November 2009, US HIV treatment guidelines recommended that a patient should start taking antiretroviral drugs when their CD4 cell count is around 350 cells/mm3. However, 54% of patients in the study had a CD4 cell count below this level.
In November 2009, new US guidelines were issued which recommend treatment for everyone with a CD4 count below 500, and also propose that people with CD4 counts over 500 should consider starting treatment too.
“These data provide strong evidence that implementation of new strategies for earlier HIV testing and effective linkage into care are urgently needed,” comment the investigators.
It is estimated that a fifth of HIV infections in the US are undiagnosed, and in Canada large numbers of people in groups with a high risk of HIV have never had an HIV test.
Late diagnosis of HIV is the reason underlying many of the HIV-related deaths in resource-rich countries, and it has been estimated that as many as 50% of all HIV transmissions originate in individuals who are unaware of their infection.
Earlier diagnosis of HIV would therefore have both individual and public health benefits, and has been prioritised by health authorities in North America as well as many western European countries.
Investigators from the North American Cohort Collaboration on Research and Design (NA-ACCORD) examined the CD4 cell counts of patients newly diagnosed with over an eleven year period, between early 1997 and the end of 2007.
A total of 44,500 patients from 22 different study populations were included in the investigators’ analysis.
Some significant changes in demographics were observed. Over time, the median age increased from 40 to 43 years (p < 0.01), and the proportion of white patients fell from 30 to 24% (p < 0.01). There was an increase in the number of patients infected heterosexually (16 to 23%, p < 0.01), and a fall in the proportion of infections attributed to injecting drug use (26 to 14%, p < 0.01).
Overall, mean CD4 cell count at the time of diagnosis increased from 256 cells/mm3 to 317 cells/mm3 (p <0.01).
Differences were apparent when the investigators looked at mean CD4 cell counts in 2007 according to demographics and risk groups.
Women had higher CD4 cell counts than men (395 cells/mm3 vs 353 cells/mm3), and black patients had lower CD4 cell counts than whites and Latinos (328 cells/mm3 vs 382 cells/mm3).
Mean CD4 cell count in 2007 was higher in gay men than other risk groups.
“Most patients continue to first present for HIV care with a CD4 count below 350 cells/mm3, the level at which initiation of antiretroviral therapy is currently recommended,” write the investigators.
They add, “a delay in presentation for treatment not only increases the chance of clinical disease progression for that patient but also increases the risk of ongoing transmission.”
The author of an editorial that accompanied the study believe that its “robust” findings “provide additional incentive for increased investment in more widespread screening for HIV”.