Overall, 761 physicians from the US and EUR5 identified 899 patients with M/S asthma, 683 with M/S CRSwNP, and 1497 with M/S AD who met the study inclusion criteria. Patient demographics are summarized by disease cohort in Online Resource 1.

Overall, at least one T2C was identified in 66%, 69%, and 46% of patients with M/S asthma, M/S CRSwNP, and M/S AD, respectively. Similar proportions were reported in the US (71%, 82%, and 51%) and EUR5 (65%, 65%, and 45%). Among patients with a primary diagnosis of M/S asthma, 3% had all three of the common T2Cs, 21% had two T2Cs, and 43% had one T2C. Similar proportions were reported in the US (1%, 17%, and 54%) and EUR5 (3%, 21% and 40%). For patients with a primary diagnosis of M/S CRSwNP, 4%, 32%, and 34% had three, two, and one T2Cs, respectively, with similar proportions reported in the US (2%, 49%, and 32%) and EUR5 (5%, 27%, and 34%). Among patients with a primary diagnosis of M/S AD, the respective proportions were 1%, 15%, and 30%. Similar proportions were reported in the US (1%, 22%, and 28%) and EUR5 (0%, 13%, and 31%).

Among patients in the M/S asthma cohort, there was a high prevalence (60%) of comorbid AR, while comorbid AD and comorbid CRSwNP occurred in 15% and 17% of cases (Fig. 1); in the US, the corresponding proportions reported were 71%, 10%, and 9%, respectively, and those for EUR5 were 58%, 16% and 19%, respectively. Prevalence of T2Cs in patients with M/S asthma across individual EUR5 countries ranged from 50 to 76% for comorbid AR, 13–24% for comorbid AD, and 12–31% for comorbid CRSwNP (Online Resource 2). Among patients in the M/S CRSwNP cohort, almost half had comorbid asthma (46%), and just over half had comorbid AR (53%); only 9% had comorbid AD (Fig. 1). The corresponding proportions in the US were 52%, 74%, and 9%, and in the EUR5 were 44%, 47%, and 9%. Prevalence of T2Cs in patients with M/S CRSwNP across individual EUR5 countries ranged from 31 to 55% for comorbid asthma, 38–55% for comorbid AR, and 7–11% for comorbid AD (Online Resource 2). Among patients in the M/S AD cohort, 27% and 32% had comorbid asthma and AR, respectively, and very few (3%) patients with M/S AD had comorbid CRSwNP (Fig. 1). The corresponding proportions in the US were 31%, 41%, and 3%, and in the EUR5 were 26%, 29%, and 4%.

Proportions of patients in each disease cohort with T2Cs: a overall; b US; c EUR5. AD atopic dermatitis, AR allergic rhinitis, CRSwNP chronic rhinosinusitis with nasal polyps, EUR5 France, Germany, Italy, Spain, United Kingdom, M/S moderate-to-severe, T2C co-existing type 2 inflammatory disease, US United States

The distribution of physician-rated severity of T2Cs among patients with M/S asthma or M/S CRSwNP is shown in Fig. 2. Mild or moderate comorbid AR was identified in 26% and 63% of the M/S asthma cohort (US: 24% and 63%; EUR5: 27% and 63%), and in 15% and 70% of the M/S CRSwNP cohort (US: 10% and 75%; EUR5: 18% and 67%). Mild or moderate comorbid AD was reported in 53% and 41% of patients in the M/S asthma cohort (US: 35% and 53%; EUR5: 56% and 39%), and in 65% and 33% in the M/S CRSwNP cohort (US: 47% for both; EUR5: 72% and 28%). Mild or moderate comorbid CRSwNP was reported in 29% and 56% of patients in the M/S asthma cohort (US: 29% and 36%; EUR5: 29% and 59%). Mild or moderate comorbid asthma was reported in 29% and 54% of patients in the M/S CRSwNP cohort (US: 25% and 60%; EUR5: 30% and 52%); results were similar in individual EUR5 countries (Fig. 3).

Physician-reported severity of T2Cs among patients with M/S asthma or M/S CRSwNP: a overall; b US; c EUR5. AD atopic dermatitis, AR allergic rhinitis, CRSwNP chronic rhinosinusitis with nasal polyps, EUR5 France, Germany, Italy, Spain, United Kingdom, M/S moderate-to-severe, T2C co-existing type 2 inflammatory disease

Physician-reported severity of T2Cs among patients with M/S asthma or M/S CRSwNP in EUR5 countries: a France; b Germany; c Italy; d Spain; e United Kingdom. AD atopic dermatitis, AR allergic rhinitis, CRSwNP chronic rhinosinusitis with nasal polyps, EUR5 France, Germany, Italy, Spain, United Kingdom, M/S moderate-to-severe, T2C co-existing type 2 inflammatory disease