Description and comparison of Crohnʼs Disease and Ulcerative Colitis in African Americans

Abstract

To compare patient characteristics, treatment response and outcome in African Americans (AA) with Crohn's disease (CD) and ulcerative colitis (UC). Single-center, retrospective study comparing 99 CD and 50 UC AA patients. Categorical variables in each group were compared using chi-square or Fisher's exact test. Continuous variables were compared using the two-group Wilcoxan rank-sum test. The level of significance was assessed at p < 0.05. Women comprised 74% of the CD cohort whereas there was equal gender distribution in the UC cohort (p= 0.0039). AA patients with CD had higher rate of surgery compared to UC patients with 61% of CD patients undergoing surgery vs.16% of UC patients (p<0.0001). Time to first surgery was shorter in CD than in UC (p= 0.0199). Traditional immune modulators or biological agents were used more often for CD patients than for UC patients. Thirty percent of CD patients had been on a biologic in the past compared to 8% of UC patients (p= 0.0022). At last observation, 36% of CD patients were being treated with a biological agent compared to 10% of those with UC (p= 0.0007). Adalimumab was used more commonly to treat CD patients whereas infliximab was used more commonly for UC patients. Thiopurine analogues were employed in treatment of CD patients more frequently than in the treatment of UC patients with 28% of CD vs.12% or UC patients on a thiopurine analogue (p= 0.0253). 5-ASA agents were used more commonly for treatment of UC patients with 68% of UC vs. 28% of CD patients on a 5-ASA agent (p<0.0001). Mesalamine Delayed-Release was the most common 5-ASA agent used to treat both CD and UC patients followed by sulfasalazine. Mesalamine was used in CD patients but none of the UC patients were on it. Lack of response and intolerance were the two most common reasons for discontinuation of immune modulators in both groups. Family history of inflammatory bowel disease (IBD) was more common in UC patients (20%) than in CD patients (14%) but this did not reach statistical significance. Twenty-two percent of UC patients had a family history of autoimmune disease vs. 8% of CD patients and it reached statistical significance (p= 0.0283). Ten percent patients from both groups had family history of colorectal cancer (CRC). Family history of cancer other than CRC was more common in UC (44%) than in CD (28%) and trended toward statistical significance (p= 0.0805). Steroid use and smoking were more common in CD without reaching statistical significance. Clinical and mucosal disease activity was higher in CD but did not reach statistical significance. Age at diagnosis, disease duration, age at last observation and BMI were greater in UC patients but they did not reach statistical significance. Notable differences between CD and UC in AA patients include differences in gender distribution, degree of genetic link to autoimmune conditions, 5-ASA agent use, immune modulator and biologic requirement including the actual biologic employed in treatment and the need for surgical intervention. CD follows a slightly more intensive course in terms of disease activity.