Factors associated with discordance between absolute CD4 cell count and CD4 cell percentage in patients coinfected with HIV and hepatitis C virus.

BACKGROUND Liver cirrhosis has been associated with decreased absolute CD4 cell counts but preserved CD4 cell percentage in human immunodeficiency virus (HIV)-negative persons. We evaluated factors associated with discordance between the absolute CD4 cell count and the CD4 cell percentage in a cohort of patients coinfected with HIV and hepatitis C virus (HCV). METHODS Baseline data from 908 participants in a prospective, Canadian, multisite cohort of individuals with HIV-HCV coinfection were analyzed. Absolute CD4 cell count and CD4 cell percentage relationships were evaluated. We defined low and high discordance between absolute CD4 cell count/CD4 cell percentage relationships as CD4 cell percentages that differed from the expected CD4 cell percentage, given the observed absolute CD4 cell count, by ±7 percentage points; we defined very low and very high discordance as differences of ±14 percentage points. Factors associated with high or very high discordance, including either end-stage liver disease or aspartate transaminase to platelet ratio index (APRI) of >1.5, were analyzed using multivariate logistic regression models and compared to groups with concordant and low discordant results. RESULTS High/very high discordance was seen in 31% (n = 286), while 35% (n = 321) had concordant values. Factors associated with very high discordance at baseline included history of end-stage liver disease (adjusted odds ratio [aOR], 6.52; 95% confidence interval [CI], 2.27-18.67) and APRI of >1.5 (aOR 4.69; 95% CI, 1.64-13.35). Compared with those with detectable HCV RNA, those who cleared HCV spontaneously were less likely to have very high discordance. CONCLUSIONS Discordance between absolute CD4 cell count and CD4 cell percentage is common in an HIV/HCV-coinfected population and is associated with advanced liver disease and ongoing HCV replication.