Discrimination of the veterans aging cohort study index 2.0 for predicting cause-specific mortality among persons with HIV in Europe and North America
People with HIV (PWH) continue to face elevated mortality risks due to comorbidities and behavioral factors. The Veterans Aging Cohort Study (VACS) Index 2.0—a prognostic tool integrating age, HIV biomarkers, and organ dysfunction indicators—has been validated for all-cause mortality. In a study published in Open Forum Infectious Diseases, Ambia et al. assessed the VACS Index 2.0’s ability to predict cause-specific mortality across 12 European and North American cohorts.
The study included 59’741 PWH on antiretroviral therapy from the Antiretroviral Therapy Cohort Collaboration (ART-CC). Cause-specific mortality was classified using the Coding of Death in HIV (CoDe) protocol. VACS Index 2.0 scores (higher scores indicate worse prognosis) were calculated at baseline (≥1 year post-ART initiation), with discrimination evaluated using Harrell’s C-statistic.
Over 168’162 person-years, 2’425 deaths occurred. The VACS Index 2.0 showed good discrimination for all-cause mortality (C-statistic: 0.83), and the mortality risk approximately doubled for every 10-unit increase in the VACS Index 2.0 score. Cause-specific discrimination was highest for AIDS-related (C-statistic: 0.91), liver-related (0.91), and respiratory deaths (0.89), reflecting the index’s emphasis on measurable organ dysfunction. In contrast, discrimination was lowest for suicide and deaths due to accidents (0.65). Notably, the VACS Index 2.0 performed better in individuals who started ART between 2010 and 2018, compared to those who started between 2000 and 2009. This was most evident for non-AIDS-defining cancers (C-statistic: 0.87 in 2010–2018 vs. 0.80 in 2000–2009).
In summary, the VACS Index 2.0 is a useful tool for estimating mortality driven by organ dysfunction and HIV progression. Identifying individuals at low or high risk of dying might help to more efficiently allocate healthcare resources to those who might benefit most. Further research is needed to assess the impact of implementing risk stratification tools such as the VACS Index 2.0.