Ulcerative colitis: correlation of the Rachmilewitz endoscopic activity index with fecal calprotectin, clinical activity, C-reactive protein, and blood leukocytes.
BACKGROUND
The accuracy of noninvasive markers for the detection of endoscopically active ulcerative colitis (UC) according the Rachmilewitz Score is so far unknown. The aim was to evaluate the correlation between endoscopic disease activity and fecal calprotectin, Clinical Activity Index, C-reactive protein (CRP), and blood leukocytes.


METHODS
UC patients undergoing colonoscopy were prospectively enrolled and scored independently according the endoscopic and clinical part of the Rachmilewitz Index. Patients and controls provided fecal and blood samples for measuring calprotectin, CRP, and leukocytes.


RESULTS
Values in UC patients (n = 134) compared to controls (n = 48): calprotectin: 396 ± 351 versus 18.1 ± 5 μg/g, CRP 16 ± 13 versus 3 ± 2 mg/L, blood leukocytes 9.9 ± 3.5 versus 5.4 ± 1.9 g/L (all P < 0.001). Endoscopic disease activity correlated closest with calprotectin (Spearman's rank correlation coefficient r = 0.834), followed by Clinical Activity Index (r = 0.672), CRP (r = 0.503), and leukocytes (r = 0.461). Calprotectin levels were significantly lower in UC patients with inactive disease (endoscopic score 0-3, calprotectin 42 ± 38 μg/g), compared to patients with mild (score 4-6, calprotectin 210 ± 121 μg/g, P < 0.001), moderate (score 7-9, calprotectin 392 ± 246 μg/g, P = 0.002), and severe disease (score 10-12, calprotectin 730 ± 291 μg/g, P < 0.001). The overall accuracy for the detection of endoscopically active disease (score ≥4) was 89% for calprotectin, 73% for Clinical Activity Index, 62% for elevated CRP, and 60% for leukocytosis.


CONCLUSIONS
Fecal calprotectin correlated closest with endoscopic disease activity, followed by Clinical Activity Index, CRP, and blood leukocytes. Furthermore, fecal calprotectin was the only marker that reliably discriminated inactive from mild, moderate, and highly active disease, which emphasizes its usefulness for activity monitoring.
Schoepfer
Alain M
AM
Department of Visceral Surgery and Medicine, Gastroenterology, Inselspital, Bern University Hospital, Bern, Switzerland. schoepf@mcmaster.ca
Beglinger
Christoph
C
Straumann
Alex
A
Trummler
Michael
M
Renzulli
Pietro
P
Seibold
Frank
F
D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002097:C-Reactive Protein / Q000032:analysis*; D003093:Colitis, Ulcerative / Q000097:blood / Q000473:pathology*; D003113:Colonoscopy; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D055815:Young Adult
D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex; D002097:C-Reactive Protein