Gender-related risk factors improve mortality predictive ability of VACS index among HIV-infected women

Background: Adding gender-related modifiable characteristics or behaviors to the Veterans Aging Cohort Study (VACS) index might improve the accuracy of predicting mortality among HIV-infected women on treatment. We evaluated the VACS index in women with HIV, determined whether additional variables would improve mortality prediction, and quantified the potential for improved survival associated with reduction in these additional risk factors. Methods: The VACS index (based on age, CD4 count, HIV-1 RNA, hemoglobin, aspartate aminotransferase, alanine aminotransferase, platelets, creatinine, and Hepatitis C status) was validated in HIV-infected women in the Women's Interagency HIV Study (WIHS) who initiated antiretroviral therapy between January 1996 and December 2007. Models were constructed adding race, depression, abuse, smoking, substance use, transactional sex, and comorbidities to determine whether predictability improved. Population attributable fractions were calculated. Results: The VACS index accurately predicted 5-year mortality in 1057 WIHS women with 1 year on highly active antiretroviral therapy with c-index 0.83 [95% confidence interval (CI): 0.79 to 0.87]. In multivariate analysis, the VACS index score [adjusted hazard ratio (aHR) for a 5-point increment 1.30; 95% CI: 1.25 to 1.35], depressive symptoms (aHR 1.73; 95% CI: 1.17 to 2.56), and history of transactional sex (aHR 1.93; 95% CI: 1.33 to 1.82) were independent statistically significant predictors of mortality. Conclusions: Both depression and transactional sex significantly improved the performance of the VACS index in predicting mortality among HIV-infected women. Providing treatment for depression and addressing economic and psychosocial instability in HIV-infected women would improve health and perhaps point to a broader public health approach to reducing HIV mortality.