title: Use of the AST to platelet ratio index in HCV/HIV co-infected patients.
abstract: BACKGROUND
  The AST to platelet ratio index (APRI), a non-invasive marker of liver fibrosis, has not been well studied in HCV/HIV (hepatitis C virus/human immunodeficiency virus) co-infected patients with advanced HIV.
  
  
  OBJECTIVE
  To compare the accuracy of APRI in HCV/HIV co-infected patients to that in HCV mono-infected patients and to determine the impact of CD4+ T-cell counts on its performance.
  
  
  METHODS
  We identified 106 consecutive HCV/HIV co-infected patients and 105 matched HCV mono-infected patients who underwent liver biopsy at Harborview Medical Center over a 5-year period. Performance characteristics were calculated and receiver operating characteristic (ROC) analysis conducted.
  
  
  RESULTS
  The area under the ROC curve (AUROC) of APRI for predicting significant fibrosis was similar when comparing those with and without HIV co-infection (0.77 vs. 0.86, P = 0.18), but was lower in HIV co-infected patients with CD4 counts <250 cells/mm³ (0.64 vs. 0.86, P = 0.05). In HIV co-infected patients with CD4 counts ≥250, APRI had higher negative predictive value (93% vs. 88%, P = 0.57), positive predictive value (63% vs. 40%, P = 0.43) and specificity (95% vs. 88%, P = 0.05) than in those with lower CD4 counts.
  
  
  CONCLUSIONS
  The AST to platelet ratio index (APRI) performance characteristics appear to be suboptimal in HCV/HIV co-infected patients with CD4 counts <250 and they require further study in this population at increased risk for advanced liver disease.
authors.affiliation: Department of Medicine, University of Texas Southwestern Medical Center, Dallas, 75390-8887, USA. amit.singal@utsouthwestern.edu
authors.forename: A G
authors.initials: AG
authors.lastname: Singal
authors.forename: L V
authors.initials: LV
authors.lastname: Thomassen
authors.forename: D R
authors.initials: DR
authors.lastname: Gretch
authors.forename: M C
authors.initials: MC
authors.lastname: Shuhart
mesh_terms: D000328:Adult; D001219:Aspartate Aminotransferases / Q000032:analysis*; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006526:Hepatitis C / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count / Q000379:methods*; D011237:Predictive Value of Tests; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D001219:Aspartate Aminotransferases