Background: The aim of this study was to examine work loss in patients with Crohn's disease.

Methods: Using nationwide registers, we identified incident patients with Crohn's disease (2007-2010) and population comparator subjects without inflammatory bowel disease, matched by age, sex, calendar year, health care region, and education level. We assessed the number of lost workdays due to sick leave and disability pension from 5 years before to 5 years after first diagnosis of Crohn's disease or end of follow-up (September 30, 2015).

Results: Among the 2015 incident Crohn's disease patients (median age, 35 years; 50% women), both the proportion with work loss and the mean annual number of lost workdays were larger 5 years before diagnosis (25%; mean, 45 days) than in the 10,067 comparators (17%; mean, 29 days). Increased work loss was seen during the year of diagnosis, after which it declined to levels similar to before diagnosis. Of all patients, 75% had no work loss 24-12 months before diagnosis. Of them, 84% had full work ability also 12-24 months after diagnosis. In patients with total work loss (8.3% of all) before diagnosis, 83% did not work after. Among those with full work ability before diagnosis, the absolute risk of having total work loss after diagnosis was 1.4% (0.43% in the comparators). Our results were consistent across several sensitivity analyses using alternative definitions for date of diagnosis.

Conclusions: Patients with Crohn's disease had increased work loss several years before diagnosis, possibly explained by comorbidity or by diagnostic delay.