Prediction of 6-thioguanine nucleotides levels in Japanese patients with inflammatory bowel diseases during long-term thiopurine administration.
BACKGROUND
The monitoring of 6-thioguanine nucleotides (6-TGN) levels is warranted during thiopurine therapy for patients with inflammatory bowel diseases.


OBJECTIVE
The aim of this study was to elucidate the parameters that can predict the 6-TGN levels among Japanese patients with inflammatory bowel diseases undergoing thiopurine therapy.


METHODS
The 6-TGN levels were measured in 54 patients with inflammatory bowel diseases (32 with ulcerative colitis and 22 with Crohn's disease), who had been administered azathioprine or 6-mercaptopurine for more than 90 days. Possible correlations between the hematologic parameters and 6-TGN levels were investigated. The clinical and hematologic variables were evaluated to determine the 6-TGN levels of less than or over 235 pmol/8 x 10(8) RBCs.


RESULTS
The 6-TGN levels correlated significantly with changes in the mean corpuscular volume (R = 0.423, p = 0.001) and the lymphocyte counts (R = -0.280, p = 0.04). A multivariate analysis revealed changes in the mean corpuscular volume (OR: 1.22, 95% CI: 1.07-1.40) and hemoglobin levels (OR: 0.59, 95% CI: 0.35-0.99) to be factors predictive of the 6-TGN levels. An increase in the mean corpuscular volume of 3.5 fl was determined to be the most preferable cut-off value to distinguish patients with 6-TGN >or= 235 pmol/8 x 10(8) RBCs from those with a lower concentration.


CONCLUSIONS
Changes in the mean corpuscular volume are considered to be predictive of the 6-TGN levels in patients with inflammatory bowel diseases receiving thiopurine therapy.
Kochi
Shuji
S
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan. decorin@intmed2.med.kyushu-u.ac.jp
Matsumoto
Takayuki
T
Esaki
Motohiro
M
Jo
Yukihiko
Y
Iida
Mitsuo
M
D000328:Adult; D001379:Azathioprine / Q000008:administration & dosage*; D054316:Biomarkers, Pharmacological / Q000097:blood; D016009:Chi-Square Distribution; D004911:Erythrocyte Volume; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy*; D007564:Japan; D016015:Logistic Models; D008297:Male; D015122:Mercaptopurine / Q000008:administration & dosage; D009711:Nucleotides / Q000097:blood*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013866:Thioguanine / Q000097:blood*
D054316:Biomarkers, Pharmacological; D009711:Nucleotides; D015122:Mercaptopurine; D013866:Thioguanine; D001379:Azathioprine