Two recent studies focused on the long-term sequelae of inflammatory bowel disease (IBD).
In the first study, researchers used the Swedish nationwide health registers from 1964 to 2014 to identify patients younger than age 18 years with a diagnosis of IBD (n=9,442) and a reference group of individuals from the general population who were matched for sex, age, calendar year, and place of residence (n=93,180). Patients with IBD had Crohn's disease (n=3,780), ulcerative colitis (n=4,671), or unclassified IBD (n=991), with a mean age of 14 years at first diagnosis. The researchers compared mortality estimates between the two groups over 138,690 person-years of follow-up.
Results were published online on Oct. 17 by Gastroenterology.
The mean age at the end of follow-up was 30 years. Overall, 294 deaths (2.1 per 1,000 person-years) occurred among patients with childhood-onset IBD, compared with 940 deaths in the reference group (0.7 per 1,000 person-years; adjusted hazard ratio, 3.2; 95% CI, 2.8 to 3.7). Hazard ratios were 4.0 for patients with ulcerative colitis (95% CI, 3.4 to 4.7), 2.3 for those with Crohn's disease (95% CI, 1.8 to 2.9), and 2.0 for those with unclassified IBD (95% CI, 1.2 to 3.4). The most common cause of death among patients with childhood-onset IBD was malignancy, followed by digestive diseases (including IBD) and infections. From 1964 through 2014, there was no significant decrease in relative mortality among young adults with IBD (P=0.90).
The study authors noted limitations, such as limited data on medications and their inability to directly assess the effect of immunomodulators and biologics on mortality. “Most patients [with childhood-onset IBD] lived as long as the general population, but the patient groups with the highest relative risk of premature death included [ulcerative colitis] patients with primary sclerosing cholangitis or with a first-degree relative with [ulcerative colitis],” they wrote.
In the second study, researchers assessed the prevalence, incidence, and predictors of malignancy in all patients with IBD in the Swiss IBD Cohort Study. Results were published online on Oct. 17 by the American Journal of Gastroenterology.
Of 3,119 patients, malignancies were identified in 122 (3.9%). The main independent predictors for the presence of malignancy were age (odds ratio, 1.04 per year; P<0.001), history of intestinal surgery (odds ratio, 3.34; P<0.001), and treatment with steroids (odds ratio, 2.10; P=0.001). In contrast, treatment with aminosalicylates (odds ratio, 0.57; P=0.019) and biologics (odds ratio, 0.38; P<0.001) was protective against malignancy. Disease location and extent were not significantly associated with malignancy.
In a longitudinal analysis, 67 of 2,580 (2.6%) patients received a new diagnosis of malignancy during a follow-up of 12,420.8 years (median, 4.9 years). Compared to the general Swiss population, patients with IBD had no increased risk for malignancy overall (standardized incidence ratio, 0.93; 95% CI, 0.72 to 1.18) or colorectal cancer (standardized incidence ratio, 1.55; 95% CI, 0.71 to 2.95). They did, however, have an increased risk for lymphoma (standardized incidence ratio, 2.98; 95% CI, 1.36 to 5.66) and biliary cancer (standardized incidence ratio, 6.3; 95% CI, 1.27 to 18.41) compared to the general population.
The study authors noted limitations, such as the fact that multivariate regression models for cancer subtypes and IBD phenotypes were not possible due to a small number of events. In addition, the study could not account for short-term adjustments of IBD treatment, they noted.