The Role Of Selected Blood Parameters In Initial Diagnosis And Activity Assessment Of Inflammatory Bowel Disease

Objective:1. To investigate whether there were significant differences in the distribution ofseveral selected blood parameters, including hemoglobin (HGB), mean corpuscularvolume (MCV), platelet count(PLT), red cell distribution width(RDW), erythrocytesedimentation rate (ESR), C-reactive protein (CRP) and mean platelet volume (MPV)between inflammatory bowel disease (IBD) and healthy control groups, or betweenCrohn’s disease (CD) and Ulcerative Colitis (UC) groups, or active and inactive IBDgroups.2. To evaluate the role of these parameters in the initial diagnosis, subtypediscrimination and activity assessment of IBD.3. To assess the role of RDW in the activity assessment of IBD by conducting adiagnostic meta-analysis.Methods：1. One hundred thirty IBD patients (including60CD and70UC) who wereresiding in Suzhou, aged18to65years and had no family history of IBD were enrolled.All patients hospitalized in Department of Gastroenterology of Suzhou MunicipalHospital (North Campus) between June2008and June2012, and were confirmed tohave been suffering from IBD according to comprehensive diagnosis. The patients werematched to130healthy controls who were free of IBD and other gastrointestinaldiseases by age and sex. Hospitalization data for patients and the data of blood test forboth IBD and controls were collected.2. The activity of the disease was assessed using the Crohn’s disease activity index(CDAI) for CD patients and the corrected Truelove-Witts index for UC patients,respectively. Active disease was defined as a CDAS of at least150for CD and a corrected Truelove-Witts index of at least11. The mean or median levels of theparameters between IBD and controls, CD and UC, active and inactive CD, active andinactive UC were respectively evaluated to detect whether there were significantdifferences in the levels of these parameters between groups. Receiver operating curve(ROC) analysis was used to determine the area under the curve (AUC), sensitivity andspecificity of these parameters in distinguishing IBD and controls, CD and UC, andactive and inactive IBD.3. A comprehensive literature search was conducted by use of multiple databasescovering Medline, ISI Web of Knowledge, Google Scholar and CNKI. A bivariatemixed-effects regression model was assigned to calculate the combined sensitivity,specificity and the AUC of RDW in assessing disease activity of IBD.Results:1. There were statistically significant differences in the levels of each parameterbetween IBD and controls (P＜0.05).2. ESR and CRP were each found to be effective in distinguishing IBD andhealthy controls, with an AUC of0.88and0.86, sensitivity of79%and82%, andspecificity of85%and79%, respectively (cut-off value was9.5mm/h for ESR and4.6mg/L for CRP).3. RDW and MCV were each shown to be effective in distinguishing CD andUC, with an AUC of0.81and0.80, sensitivity of76%and70%, and specificity of72%and73%, respectively (cut-off value was13.5for RDW and87.9fL forMCV). Further analyses found that the observed diagnostic value of RDW waslimited in distinguishing active CD and active UC.4. CRP followed by RDW and ESR were effective in the activity assessmentof CD, all with AUCs of over0.80. CRP had a sensitivity and a specificity of85%and75%, respectively, in discrimination between active and inactive CD, whengiven a cut-off value of6.5mg/L; none of the studied blood parameters was shown tobe able to effectively evaluate the activity of UC, with the most effective one (RDW)achieving an AUC of merely0.73.5. Six studies that totaled996IBD patients (451CD and545UC) were included inthe diagnostic meta-analysis. The combined sensitivity and specificity for RDW todetect active patients among CD was79%(95%CI,70-85%) and78%(95%CI， 68-88%), and the combined AUC was0.84(95%CI,0.81-0.87); Whereas RDW wasshown to specifically (79%), but not sensitively (64%) detect active patients among UC.Conclusion:Both CRP and ESR are sensitive and specific in the initial diagnosis and activityassessment of IBD (limited to CD); RDW may serve as a new parameter in blood that issimple, inexpensive, sensitive and specific in the discrimination of subtypes and activityassessment of IBD (limited to CD).