Histologic Remission and Mortality in Patients With Inflammatory Bowel Disease: A Nationwide Cohort Study

Inflammatory bowel disease (IBD) is associated with increased mortality risk. However, whether this risk is influenced by histologic and clinical activity remains uncertain.

A nationwide cohort study in Sweden. We compared mortality rates linked to histologic inflammation in 63,358 patients diagnosed with IBD 1969-2017 and to clinical activity in 102,352 patients diagnosed 1969-2020. The adjusted hazard ratio (aHR) of mortality within 2 years after index date (ie, date of histologic/clinical activity) was estimated using cause-specific hazard model, with 95% confidence intervals (CIs).

A higher 2-year all-cause mortality was observed after histologic inflammation than after histologic remission (mortality rate: 121.0 vs 64.8 per 10,000 person-years; aHR, 1.45; 95% CI, 1.30-1.61). This excess risk was observed in all IBD subtypes: Crohn's disease (aHR, 1.42; 95% CI, 1.16-1.73), ulcerative colitis (aHR, 1.44; 95% CI, 1.26-1.65), and IBD unclassified (aHR, 1.56; 95% CI, 1.01-2.41). Clinically active IBD was also associated with an increased 2-year all-cause mortality compared to quiescent IBD (mortality rate: 352.6 vs 106.3 per 10,000 person-years; aHR, 3.35; 95% CI, 3.21-3.49). Even in patients with clinically quiescent IBD, histologic inflammation was associated with an increased 2-year all-cause mortality (aHR, 1.42; 95% CI, 1.08-1.87).

Both histologic inflammation and clinical activity of IBD were associated with increased all-cause mortality, suggesting that improved disease control may reduce mortality risk in IBD.