Fecal alpha 1-antitrypsin as a measure of Crohn's disease activity. The effect of therapy and anatomical extent of disease.

Random fecal alpha 1-antitrypsin levels, determined in 35 patients with Crohn's disease, showed a strong correlation with clinical activity (Spearman r = 0.44, p = 0.01). In 85% of the patients, both clinical and fecal measurements of Crohn's disease activity agreed (kappa = 0.368, p = 0.011). Similar agreement occurred in those with colitis (kappa = 0.385, p = 0.035) or ileitis (binomial, p less than 0.001) and those with (binomial, p = 0.006) or without (kappa = 0.492, p = 0.01) prior surgery. There was a reduction in the mean clinical score and fecal levels among all patient groups after treatment. There was good agreement between both disease activity measurements after medical therapy. However, even after apparent surgical "cure," fecal protein levels generally remained at values consistent with diffuse occult intestinal disease. When surgical removal of all diseased bowel was not possible, fecal measurements again appeared superior to clinical assessment in reflecting the residual disease. A good correlation existed between the anatomical extent of disease and fecal levels (r = 0.606, p = 0.028), in contrast to the relationship between extent and clinical score (r = 0.14, p = 0.64). Random fecal alpha 1-antitrypsin determinations provide a measure of the intestinal activity and extent of Crohn's disease. They may be useful in monitoring the response to therapy and the presence of residual disease after surgery.