Description of Study Population
A total of 239 patients were recruited, 220 (92.1%) of whom were included in the analysis of the first year as they had complete data for the main variables and so were considered evaluable, and 120 (50.2%) evaluable patients were included in the analysis of the second year. Mean age was 49.1 (SD 13.8) years and 71.8% of patients were female. Regarding clinical characteristics, mean time since diagnosis of asthma was 20.0 (13.4) years, and mean pre-bronchodilator FEV1 was 66.9% (20.9). The median baseline values for peripheral eosinophils in blood, IgE and fractional exhaled nitric oxide (FeNO) were 385 cells/µL, 571 IU/mL and 32 parts per billion (ppb), respectively. More clinical data are available in Table 1.
Effectiveness of Omalizumab
The mean number of exacerbations, calculated as prednisone cycles with or without a visit to the emergency department or hospitalization, was 7.6 (7.7) in the year prior to omalizumab prescription and 1.4 (2.9) after 1 year of omalizumab treatment (p < 0.001). The mean number of exacerbations, calculated as prednisone cycles without a visit to the emergency department or hospitalization, was also lower after omalizumab treatment. Mean ACT score was higher after 1 year of omalizumab treatment (11.5 [3.4] vs 19.9 [3.7]: p < 0.001) and the number of patients with uncontrolled asthma, according the ACT results, was − 76.3% lower (88.7% vs 12.4%; p < 0.001). Lung function improved +10.8 points after 1 year of treatment with omalizumab, as mean pre-bronchodilator FEV1 was 66.9% (20.9) in the previous year and 77.7% (21.6) after 1 year on omalizumab treatment (p < 0.001). Patients’ perception of disease progression was positive in > 92% of patients after omalizumab treatment, compared with only 6.4% in the previous year (p < 0.001). An improvement in rhinitis was also observed after omalizumab treatment, as 53.8% of patients reported better control compared with 3.7% in the previous period (p < 0.001). Mean eosinophil count fell from 387 (385) to 302 (280) cells/µL (p < 0.004) after 1 year on omalizumab treatment (Table 2).
Social, Healthcare and Pharmacological Resources
The number of short-term cycles of prednisone pre- and post-omalizumab decreased by 58.3% (p < 0.001), while the number of long-term cycles decreased by 80.7% (p < 0.001).
The mean number of hospital admissions per year during the pre-omalizumab period M (P25; Me; P75) was 0.38 (0.0; 0.0; 1.0), with a mean duration of 2.83 (0.0; 0.0; 3.0) days per admission, and 0.05 (0.0; 0.0; 0.0) in the first year (p < 0.001), with a mean duration of 0.32 (0.0; 0.0; 0.0) days per admission (p < 0.001). Non-scheduled visits to both primary care and the respiratory medicine department reduced in the first year of omalizumab treatment. When the first and second years of treatment with omalizumab were compared, no such differences in the use of healthcare resources were observed (Table 3).
The number of patients treated with ICS, leukotriene receptor antagonists, anticholinergics and oral corticosteroids (OCS) were significantly lower in the first year of omalizumab treatment than in the previous year. Similarly, the mean number of medications for the treatment of rhinitis needed by each patient also reduced. However, no significant differences were observed in the frequency of use of asthma medication between the first and the second year of treatment with omalizumab (Table 4).
The mean number of days of absence from work per patient was 19.60 (0.0; 5.0; 30.0) in the year prior to omalizumab prescription and 1.09 (0.0; 0.0; 0.0) in the first year of treatment (p < 0.001). No differences were observed in the number of days of absence from work during the first or second year of treatment with omalizumab.
Costs of Omalizumab
Asthma management costs related to healthcare resources only (i.e., excluding cost of medication) were €717 (321; 642; 645) per patient-year over the first year of treatment with omalizumab, and €1952 (260; 569; 2415) in the previous year (p < 0.001) (Table 5), signifying a €1235 difference (95% CI 1695–895).
Costs of pharmacological treatment for the management of asthma other than omalizumab were €1261 (1003; 1082; 1512) per patient-year in the pre-omalizumab period and €376 (263; 264; 488) in the first year post-omalizumab, with the difference between the two periods being −€884 (95% CI − 953 to − 820) (Table 6). The use of omalizumab represented a mean cost of €12,690 (8198; 9202; 16,400) per patient-year. Consequently, the difference in total costs of pharmacological treatment between pre- and post-omalizumab periods was +€11,799 (95% CI 10,886–12,787).
Indirect costs resulting from days of absence from work fell after omalizumab prescription from €697.9 (0.0; 0.0; 784.3) to €51.5 (0.0; 0.0; 0.0) (p < 0.001). Therefore, taking into account both direct and indirect costs, the mean cost of the pre-omalizumab period was €3911 (1468; 2485; 4847) and the post-omalizumab period was €13,890 (8712; 12,430; 17,520) (p < 0.001), a difference of €9979 (95% CI 8841–11,056).
No significant differences were found in costs of healthcare resources, pharmacological treatment or in indirect costs during the first and the second years of omalizumab treatment (data not shown).
Cost-Effectiveness of Omalizumab
ICER was assessed for the incorporation of omalizumab into patient treatment, resulting in €1712 (95% CI 1487–1995) per avoided exacerbation, in contrast with the pre-omalizumab period. When both direct and indirect costs were taken into account, the ICER was €1607 (95% CI 1385–1885) for every avoided exacerbation.
ICER resulted in €3859 (95% CI 3327–4418) for every clinically significant change in asthma control (3-point increase in the ACT) . When indirect costs were included, the ICER was €3555 (95% CI 3012–4125) for every 3-point increase.