Drug survival of omalizumab and antihistamines among chronic urticaria patients

Aim: Chronic urticaria is a disease with a frequency of approximately 1.8% in the population, negatively affecting the quality of life. The unpredictability of the duration of the disease and the limited treatment options make disease management difficult. In recent years, patient groups have been defined who respond distinctly to the treatment. In our study, we aimed to determine the drug survival of the omalizumab and antihistamine therapy along with the patients and disease characteristics. Materials and Method: This retrospective observational study was conducted by Karadeniz Technical University Faculty of Medicine, Department of Dermatology and Venereology. A total of 93 newly or previously diagnosed chronic urticaria patients, who were referred to our outpatient clinics between March 2022 and March 2023, were included in the study. Age, gender, body mass index, medical and family history, received treatments, duration of the treatments, variables related to the disease, as well as the laboratory values at the beginning and follow-up of the treatment were recorded in the case report form during the patient visits for each patient. In addition, further data was obtained from the hospital registry system. Findings: Of the 93 chronic urticaria patients included in this study, 70 (75.3%) were female and 23 (24.7%) were male. Of 93 patients, 61.3% (n=57) used omalizumab at some stage of their illness, and the remaining 38.7% (n=36) received treatment with only antihistamines. Of the 56 patients using omalizumab, 40 discontinued treatment at least once for some reason. Among the 15 patients who discontinued treatment, 10 (66.7%) due to recovery, 2 (13.3%) due to loss to follow-up, 1 (6.7%) due to inappropriate precription in an external center, 1 (6.7%) due to inefficacy and 1 (6.7%) terminated omalizumab due to pregnancy wish. By Kaplan- Meier analysis, the median duration of treatment in the first omalizumab cycle was 9 months in 56 patients who received omalizumab treatment. The median duration of antihistamine treatment was 67 months for all CU patients. The median time under omalizumab was 21 months. The time spent under omalizumab was found to be significantly longer in patients who had emergency admission during omalizumab treatment compared to those who did not v (p=0.02). A statistically significant (p=0.008) strong positive correlation was found between the fibrinogen level at the beginning of the treatment (n=15) and the time spent under omalizumab. Baseline fibrinogen level was significantly positively correlated with the total number of omalizumab administration (p=0.02). Baseline bazophil level was negatively correlated with the disease duration. The median disease duration was found to be significantly longer (p=0.009) in patients who required maximum antihistamine dosis. The duration of illness was found to be significantly longer in patients admitted to the emergency department under omalizumab, in need of glucocorticoids, in patients with asthma, food allergy, and mite allergy compared to those who lack the former features (p = 0.023 and p=0.002, p=0.046, p=0.023, p =0.041, respectively). After switching to omalizumab, emergency admissions decreased signicantly (p=0.04). Baseline leukocyte and neutrophil and anti-TPO levels decreased significantly in follow-up (p=0.02, p=0.006, p=0,045 respectively). Total IgE value was found to rise signicantly in the follow-up (p=0.021). Results: It was shown that omalizumab decreased the need of hospitalisation and emergency admission. Higher baseline fibrinogen levels, requiring maximum antihistamine dosis, need for ermergency admission under omalizumab, requiring corticosteroids for disease control, personal history of asthma, food and dust mite hypersensitivity were associated with longer disease duration. Baseline basophil levels were negatively correlated with disease duration.