Albumin, white blood cell count, and body mass index improve discrimination of mortality in HIV-positive individuals. AIDS
The Veterans Aging Cohort Study (VACS) Index incorporates clinical biomarkers of general health with age, CD4+ cell count, and HIV-1 RNA to discriminate mortality risk in a variety of HIV-positive populations.
In the current study, the author team aimed to develop an improved VACS Index (2.0), externally validate using data from European and North American cohorts participating in the Antiretroviral Therapy Cohort Collaboration (ART-CC), and evaluate generalizability among important subgroups. They obtained laboratory values from a randomly selected visit from 2000 to 2014, at least 1 year after antiretroviral therapy initiation. Patients were then followed for 5-year, all-cause mortality through September 2016.
Among 28’390 VACS patients and 12’109 ART-CC patients, 7’293 and 722 died, respectively. Nadir CD4+, CD8+, and CD4+ : CD8+ ratio did not improve discrimination. Addition of albumin, white blood count, and BMI, improved c-statistics in VACS from 0.776 to 0.805 and in ART-CC from 0.800 to 0.831. Results were robust in all nine ART-CC cohorts, all lengths of follow-up and all subgroups.
In conclusion, VACS Index 2.0 was highly predictive of risk of all-cause mortality among those on treatment for HIV infection. With use of continuous variables, VACS Index 2.0 is now better suited to application for individual patients. With addition of parameters readily obtained during routine clinical practice, VACS Index 2.0 is more discriminating than the original VACS Index. Its superior discrimination is robust across development and validation sets, among important clinical subgroups, and among individual cohorts.