Determination of the cut-off value of serum alanine aminotransferase in patients undergoing hemodialysis, to identify biochemical activity in patients with hepatitis C viremia.
BACKGROUND
Elevated liver enzymes are infrequent in patients with hepatitis C virus (HCV) infection undergoing chronic hemodialysis (HD), suggesting that the alanine aminotransferase (ALT) is a poor predictor of hepatocellular damage in this population.


OBJECTIVE
To establish a more appropriate cut-off value of ALT to identify biochemical activity due to HCV infection in HD patients.


METHODS
A total of 217 patients, with an average age of 51.2 years, were evaluated between January and October 2002; 130 were males (60%). Serum ALT was measured by a kinetic method in five consecutive monthly blood samples, from which an average was obtained and divided by the upper limit of normal (ULN). HCV antibodies were determined using an enzyme immunoassay, the serum HCV-RNA by nested-PCR and HCV genotype by hybridization of the amplified sequence from the 5'-non-coding region. The cut-off value of ALT was obtained from a ROC curve.


RESULTS
Within the 217 patients, 18 (8.3%) were anti-HCV-positive, 17 (7.8%) of whom were also HCV-RNA-positive. Genotype distribution was: 1a=47%; 1b=18%; 3a=35%. Mean ALT/ULN (0.77+/-0.57) of the 18 anti-HCV-positive cases was higher (p<0.001) than the negative group (0.38+/-0.23). The mean ALT/ULN (0.81+/-0.57) of the 17 HCV-RNA-positive cases was also higher (p<0.0001) than the negative cases (0.37+/-0.23). The cut-off value of ALT to distinguish the anti-HCV-positive from negative patients was 0.50% or 50% of the ULN (sensitivity=67%; specificity=83%). According to the HCV-RNA, the cut-off value of ALT was 0.45% or 45% of the ULN (sensitivity=71%; specificity=80%).


CONCLUSIONS
Reducing the cut-off of ALT by half, enables a better identification of biochemical activity in patients with HCV infection on chronic HD.
Lopes
E P A
EP
Department of Medicine, Federal University of Pernambuco (UFPE), Rua Irmã Maria David, 154/Apto. 3201, 52061-070 Recife, PE, Brazil. epalopes@ufpe.br
Gouveia
E C
EC
Albuquerque
A C C
AC
Sette
L H B C
LH
Mello
L A
LA
Moreira
R C
RC
Coelho
M R C D
MR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000410:Alanine Transaminase / Q000097:blood*; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D006526:Hepatitis C / Q000201:enzymology / Q000503:physiopathology*; D018937:Hepatitis C Antibodies / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000097:blood / Q000235:genetics; D012016:Reference Values; D006435:Renal Dialysis; D014766:Viremia
D018937:Hepatitis C Antibodies; D012367:RNA, Viral; D000410:Alanine Transaminase