Clinical and laboratory indicators of extent of ulcerative colitis. Serum C-reactive protein helps the most.

We estimated the extent of the inflammatory mucosal lesion by colonoscopy and biopsy in 60 patients with their first attack of ulcerative colitis. Proctitis was found in 12, proctosigmoiditis in 19, left-sided colitis in 10, and extensive colitis in 19. Fourteen clinical variables and laboratory measurements (bowel frequency, stool consistency, rectal bleeding, fecal mucus/pus, temperature, pulse rate, white blood cell count, hematocrit, sedimentation rate, serum iron, serum albumin, serum alpha 2-globulin, serum C-reactive protein, and seromucoids) were determined. All the variables except rectal bleeding and hematocrit were correlated (p less than 0.001) with the extent of colitis. On stepwise discriminant analysis, only C-reactive protein distinguished proctosigmoiditis from more improved the discrimination. Cross-validation by the "jack-knife method" showed that 86.7% of patients were correctly classified, the errors consisting in underestimation of disease in 8/29 patients with extensive colitis.