Reply to Post and Sabin

Abstract

To the Editor—As described in their letter, Post and Sabin found that an elevated aspartate aminotransferase-to-platelet ratio index (APRI) was predictive of all-cause mortality in a large cohort of individuals infected with human immunodeficiency virus (HIV) [1]. Notably, high APRI were associated with mortality among patients coinfected with HIV and hepatitis virus and among patients monoinfected with HIV. Interestingly, as in our study, the researchers found a relatively high prevalence (7%) of APRI consistent with significant fibrosis among HIV-monoinfected subjects, and they observed an association between higher APRI and both high HIV RNA levels and lower CD4+ T-cell counts [2]. Their finding of an increased risk of all-cause mortality among subjects with an elevated APRI is intriguing and deserves further study. We are interested in knowing the causes of death among the subjects who died and whether the causes of death were similar for people with high APRI and those with low APRI. The APRI has been found to be predictive of all-cause and liver-related mortality in cohorts of individuals with HIV and viral hepatitis coinfection [3, 4]. However, until now, the association between APRI and mortality among HIV-monoinfected subjects had not been evaluated. Thus, Post and Sabin have verified our findings of high APRI in HIV-monoinfected subjects and have found that these high values predict all-cause mortality. Further work is needed to understand the reasons for elevated APRI in the setting of HIV monoinfection, to determine whether an elevated APRI reflects liver disease stage, and to determine the influence of highly active antiretroviral therapy on APRI.