Dissecting Lewis score under the light of fecal calprotectin; an analysis of correlation of score components with calprotectin levels in capsule endoscopy

BACKGROUND Lewis Score (LS) is an inflammatory score in small-bowel capsule endoscopy (SBCE). Fecal calprotectin (FC) is considered the non-invasive, 'gold standard' marker of gastrointestinal (GI) inflammation. Recently, we reported that LS shows only a moderate correlation with FC. In this study, we aim to evaluate which LS parameters have greater correlation with FC. METHODS A retrospective, two-center study; 74 patients who underwent SBCE within 7 (median 1.5) days from a FC measurement. LS was calculated; univariate and multivariate analyses were performed, investigating LS correlation with FC, and which LS parameters had stronger correlation coefficient (rs) with FC. RESULTS 74 patients had an FC measurement within 7 days of their SBCE examination (median 22 time-interval: 1.5 days; IQR: 5). Coefficient rs between LS and FC was moderate (0.454). In univariate analysis, the variables that gave the strongest association with FC were: the higher tertile subscore for ulcer, the summative ulcer subscore, the higher tertile ulcer score (only with descriptors of ulcer size and number), the summative ulcer score (only with descriptors of ulcer size and number), and subscores including various combinations of the stenosis descriptors. In multivariate analysis, the only positive predictor for FC was the higher tertile ulcer subscore (only with descriptors of ulcer size and number). CONCLUSION LS shows only moderate correlation to FC. This is due to a) an inherent limitation of LS, and b) the notion of correlating the 2 parameters, and consideration should be given to development of a new, simplified (or composite) inflammation score/index for SBCE.