Demographics and clinical characteristics during the pre-mepolizumab treatment period (baseline)

Total population368
Age at enrolment years (n=367)
 Median (IQR)54.0 (44.0–63.0)
Female (n=367)226 (62)
 White/Caucasian337 (92)
 Asian, Native Hawaiian or other Pacific Islander17 (5)
 Black/African-American5 (1)
 Other/multiple9 (2)
 UK136 (37)
 Italy87 (24)
 Germany44 (12)
 Canada40 (11)
 Belgium29 (8)
 Spain24 (7)
 USA8 (2)
BMI at enrolment kg·m−2
 Median (IQR)27.5 (23.7–32.4)
Smoking history at enrolment (n=364)
 Never-smoker221 (61)
 Current smoker10 (3)
 Ex-smoker133 (37)
Asthma duration at enrolment years (n=360)
 Median (IQR)17.41 (7.00–30.66)
Previous use of omalizumab (n=365)71 (19)#
Duration of omalizumab treatment months (n=70)
 Median (IQR)14.5 (6.0–48.0)
Maintenance OCS use at enrolment (n=365)
 Never108 (30)
 Past83 (23)
 Current174 (48)
Daily maintenance OCS dose+ mg·day−1 (n=159)
 Median (IQR)10.0 (5.0–15.0)
Rate of exacerbations per person per year (n=366)
 Clinically significant exacerbations
  Median (IQR)3.0 (2.0–6.0)
 Exacerbations requiring hospitalisation and/or emergency department visit
  Median (IQR)0 (0.0–1.0)
 Exacerbations requiring hospitalisation
  Median (IQR)0 (0.0–1.0)
Blood eosinophil count§ cells·µL−1 (n=357)
 Geometric mean±sd logs370±1.248
 Median (IQR)442 (270–800)
 <15051 (14)
 150– <30045 (13)
 ≥300261 (73)
Lung function§
 Pre-bronchodilator FEV1 L (n=201)
  Median (IQR)1.84 (1.39–2.42)
 Pre-bronchodilator FVC L (n=201)
  Median (IQR)2.82 (2.28–3.57)
 Pre-bronchodilator FEV1/FVC (n=201)
  Median (IQR)0.66 (0.58–0.73)
 Pre-bronchodilator FEV1 % pred (n=200)
  Median (IQR)65.65 (47.60–80.33)
 Reversibility % (n=39)
  Median (IQR)4.93 (0.90–13.48)
 Post-bronchodilator FEV1 L (n=70)
  Median (IQR)2.08 (1.34–2.72)
 Post-bronchodilator FVC L (n=70)
  Median (IQR)3.04 (2.10–3.88)
 Post-bronchodilator FEV1/FVC (n=70)
  Median (IQR)0.67 (0.58–0.75)
 Post-bronchodilator FEV1 % pred (n=70)
  Median (IQR)69.10 (48.09–85.25)
ACQ-5 score§ (n=350)
 Median (IQR)3.2 (2.2–4.0)
Medical history reported during 12 months prior to the enrolment date
 Any343 (93)
  Recognised to be associated with asthma
   Any asthma related292 (79)
   Hay fever193 (52)
   Chronic sinusitis145 (39)
   Nasal polyps140 (38)
   Any drug hypersensitivity127 (35)
   Nasal polypectomy96 (26)
   Atopic dermatitis47 (13)
   Anaphylaxis24 (7)
  Conditions of interest (reported in ≥5% of patients)
   Any condition of interest285 (77)
   Gastro-oesophageal reflux disease137 (37)
   Depression73 (20)
   Osteoporosis66 (18)
   Anxiety59 (16)
   Hyperlipidaemia58 (16)
   Food allergy47 (13)
   Fractures40 (11)
   Diabetes36 (10)
   Cataract34 (9)
   Pneumoniaƒ34 (9)
   COPD33 (9)
   Oropharyngeal candidiasis33 (9)

Data are presented as n or n (%), unless otherwise stated; percentages may not add up to 100% due to rounding. IQR: interquartile range; BMI: body mass index; OCS: oral corticosteroid; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; ACQ-5: five-item Asthma Control Questionnaire; COPD: chronic obstructive pulmonary disease. #: during the enrolment period, 13 out of 71 (18%) patients had received omalizumab treatment outside of a clinical trial and the remaining 58 out of 71 (82%) patients had received omalizumab treatment >12 months prior to enrolment that may have been within or outside of a clinical trial (data were collected for 12 months prior to enrolment only); in those patients who received omalizumab in the prior 12 months, typically, the end of omalizumab treatment was ∼1–2 months prior to starting mepolizumab. : reported by the patient. +: during the period including the index date and the 27 days prior to index or any other 27-day period in the last 6 months if no records existed 27 days immediately prior to index. §: latest record prior to index. ƒ: pneumonia cases were limited to the prior 12 months.