5-ASA maintenance therapy of little help in patients with newly diagnosed CD

Maintenance treatment with 5-aminosalicylates (5-ASA) in patients with newly diagnosed Crohn's disease (CD) does not appear to lead to better outcomes as compared with a watchful waiting approach, according to a study.

For the study, data from the epidemiological cohort of the Israeli-Inflammatory Bowel Diseases Research Nucleus were used. Propensity score (PS) matching facilitated comparison of outcomes in the 5-ASA maintenance therapy group versus the no-treatment group.

Of the 19,264 patients diagnosed with CD, 8,610 (45 percent) met the eligibility criteria and were included in the analysis. Of these, 3,027 (16 percent) patients received 5-ASA maintenance therapy and 5,583 (29 percent) received no treatment.

The use of either treatment strategy declined over the years. Specifically, 5-ASA maintenance therapy was used in 21 percent of CD patients diagnosed in 2005 and in only 11 percent of patients diagnosed in 2019 (p<0.001). On the other hand, the use of a watchful waiting approach decreased from 36 percent in 2005 to 23 percent in 2019 (p<0.001).

In the 5-ASA group, the probability of maintaining therapy was 78 percent at 1 year, 57 percent at 3 years, and 47 percent at 5 years from diagnosis. In the no-treatment group, the corresponding probabilities were 76 percent at 1 year, 49 percent at 3 years, and 38 percent at 5 years (p<0.001).

Propensity score analysis included 1,993 pairs of treated and untreated patients. No significant differences were observed in terms of time to biologic initiation (p=0.2), steroid dependency (p=0.9), hospitalization (p=0.5), and CD-related surgery (p=0.1).

Before propensity-score matching, the 5-ASA group had significantly higher frequency of acute kidney injury (5.2 percent vs 3.3 percent; p<0.001) and pancreatitis (2.4 percent vs 1.8 percent; p=0.03) as compared with the no-treatment group. However, these differences disappeared after propensity-score matching.

The present data suggest that a watchful waiting approach is feasible in a subset of patients with mild CD.