Correlation between levels of C-reactive protein and clinical activity in Crohn's disease

To determine the factors associated with an increased C-reactive protein level in Crohn's disease patients and to seek a correlation between the C-reactive protein value and the Crohn's disease activity index.

We prospectively studied 103 Crohn's disease patients, 76% of whose disease was active at the time of inclusion. C-reactive protein measurement was carried out on all patients. An increased C-reactive protein level was defined as >/=10mg/L.

The median C-reactive protein rate was 53.9mg/L (ranging from 1 to 228mg/L). An increased C-reactive protein was found in 77 patients (75%). By univariate analysis, ileocolic localization, severity of the flare, erythrocyte sedimentation rate, leukocyte and platelet count, fibrinogen, albumin, serum calcium and Crohn's disease activity index were found to be associated to elevated C-reactive protein values. By multivariate analysis, independent factors associated with an increased C-reactive protein level were: ileocolic localization (p=0.02; OR [95% CI]: 2.84 [1.25-9.52]) and moderate or severe disease activity (p=0.001; OR [95% CI]: 4.20 [1.92-8.64]). A statistically significant association between the Crohn's disease activity index score and the C-reactive protein level was found in our study (r=0.302; p=0.001). The optimal C-reactive protein threshold value that separates patients with moderate to severe disease (Crohn's disease activity index>220) from the others was calculated to be 19mg/L with a sensitivity of 76.4% and a specificity of 56.2%.

The C-reactive protein level is correlated to disease activity in Crohn's disease. Its role seems to be essential in predicting moderate and severe disease activity.