The higher mortality rate for patients with HIV subtype D is independent of viral load set point, according to results published in AIDS Research and Human Retroviruses.
The study included participants from the Rakai Community Cohort Study (RCCS) aged 15 to 49 years. Participants were enrolled and received follow-up at approximately 12- to 18-month intervals from January 1995 through October 2007. The researchers analyzed participants with HIV subtypes A or D, excluding those with recombinant and/or multiple infections.
To estimate time to AIDS or AIDS-related death, the researchers used Kaplan-Meier survival analysis stratified by subtype and viral set point as well as Cox proportional hazards regression with an interaction term between viral load set point and HIV subtype.
Of 375 participants, 20.8% (n=78) were infected with subtype A and 79.2% (n=297) were infected with subtype D.
The results did not indicate effect measures modification between viral load set-point and progression to AIDS by HIV-1 subtype (adjusted hazard ratio [aHR], 0.99; 95% CI, 0.61–1.61; P =.968).
The researchers did not find a difference in relationship between viral load set point and time to AIDS with overlapping 95% CIs between subtypes A and D (subtype A aHR, 2.40; 95% CI, 1.45–3.99; subtype D aHR, 1.96; 95% CI, 1.60–2.40).
“Based on this analysis, there did not appear to be any significant excess risk resulting from the pathogenic effects of having both a subtype D HIV‐1 infection and a high set‐point viral load,” the researchers wrote.
McPhee E, Grabowski MK, Gray RH, et al. The interaction of HIV set point viral load and subtype on disease progression. AIDS Res Hum Retroviruses. 2019;35(1):49-51.