title: High-sensitivity C-reactive protein for identification of disease phenotype, active disease, and clinical relapses in Crohn's disease: a marker for patient classification?
abstract: BACKGROUND
  C-reactive protein (CRP) is a traditional nonspecific marker of inflammation, with Crohn's disease (CD) being associated with a strong CRP response. Thus far, no clear cutoff values have been determined. The authors' aim was to investigate whether high-sensitivity (hs)-CRP is useful for the identification disease phenotype, active disease, and relapse during follow-up, using a classification based on the hs-CRP value at diagnosis.
  
  
  METHODS
  In all, 260 well-characterized, unrelated, consecutive CD patients (male/female: 120/140; duration: 7.0 ± 6.1 years), with a complete clinical follow-up, were included. Hs-CRP, clinical activity according to the Harvey-Bradshaw Index, and clinical data (disease phenotype according to the Montreal Classification, extraintestinal manifestations, smoking habits, medical therapy, and surgical events) were prospectively collected between January 1, 2008 and June 1, 2010. Medical records prior to the prospective follow-up period were analyzed retrospectively.
  
  
  RESULTS
  In all, 32.3% of CD patients had normal hs-CRP at diagnosis. Elevated hs-CRP at diagnosis was associated with disease location (P = 0.002), noninflammatory disease behavior (P = 0.058), and a subsequent need for later azathioprine/biological therapy (P < 0.001 and P = 0.024), respectively. The accuracy of hs-CRP for identifying patients with active disease during prospective follow-up was good (area under the curve [AUC]: 0.82, cutoff: 10.7 mg/L). AUC was better in patients with an elevated hs-CRP at diagnosis (AUC: 0.92, cutoff: 10.3 mg/L). In Kaplan-Meier and Cox-regression analyses, hs-CRP was an independent predictor of 3- (P = 0.007) or 12-month (P = 0.001) clinical relapses for patients in remission who had elevated hs-CRP at diagnosis. In addition, perianal involvement (P = 0.01) was associated with the 12-month relapse frequency.
  
  
  CONCLUSIONS
  Our data suggest that hs-CRP positivity at diagnosis is associated with disease location and behavior, and in patients who are hs-CRP positive at diagnosis, is an accurate marker of disease activity and a predictor of short- and medium-term clinical flare-ups during follow-up.
authors.affiliation: 1st Department of Medicine, Semmelweis University, Budapest, Hungary.
authors.forename: Lajos Sandor
authors.initials: LS
authors.lastname: Kiss
authors.forename: Maria
authors.initials: M
authors.lastname: Papp
authors.forename: Barbara Dorottya
authors.initials: BD
authors.lastname: Lovasz
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Vegh
authors.forename: Petra Anna
authors.initials: PA
authors.lastname: Golovics
authors.forename: Eszter
authors.initials: E
authors.lastname: Janka
authors.forename: Eva
authors.initials: E
authors.lastname: Varga
authors.forename: Miklos
authors.initials: M
authors.lastname: Szathmari
authors.forename: Peter Laszlo
authors.initials: PL
authors.lastname: Lakatos
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism*; D003424:Crohn Disease / Q000145:classification* / Q000175:diagnosis* / Q000378:metabolism; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010641:Phenotype; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence; D012017:Referral and Consultation
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein