D1.447 - Comparison of Disease Duration, Remission, and Other Disease-Related Parameters with the Duration of Omalizumab Treatment in Patients with Chronic Spontaneous Urticaria

Omalizumab is a biological agent frequently used in antihistamine-resistant chronic spontaneous urticaria(CSU), from which the majority of patients benefit. In our study, we aimed to compare the duration of omalizumab treatment with disease duration, remission, and other disease-related parameters in patients with CSU who received omalizumab treatment in our clinic.

The data of a total of 175 patients with CSU who used or have been using omalizumab and were followed in our clinic between January 2015 and December 2025 were reviewed retrospectively. Patients were divided into three groups based on omalizumab treatment duration (Group 1: 1–24 months, Group 2: 25–60 months, Group 3: 60 months over), and disease duration (before omalizumab therapy), remission, and disease-related parameters were compared. Patients who remained asymptomatic for at least six months after discontinuation of omalizumab therapy were considered to be in remission.

Comparisons between the three groups revealed no statistically significant differences in age, sex, high IgE, sIgE positivity, angioedema, atopic disease, ANA positivity, TSH, thyroid disease, anti-TPO positivity, low complement C3, low complement C4, tryptase and remission parameters. However, significant differences were found between the groups in disease duration, erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP). Therefore, pairwise comparisons (Mann-Whitney U) were performed to identify which groups accounted for these differences. Significant differences were found between Groups 1 and 2 in CRP (p = 0.033); between Groups 1 and 3 in disease duration (p = 0.001) and ESR (p = 0.011); and between Groups 2 and 3 in disease duration (p = 0.033) and ESR (p = 0.033).When comparing the three groups as a whole, the statistically significant differences in disease duration and ESR were attributed to Group 3.

Although not statistically significant, patients with shorter disease duration demonstrated higher remission rates. Patients receiving long-term omalizumab therapy were found to have significantly higher erythrocyte sedimentation levels, which was associated with chronic inflammation.The most striking finding of the study was the positive correlation between pre-omalizumab disease duration and omalizumab treatment duration. This result suggests that the longer the disease duration, the longer omalizumab therapy will be required.