Table 1 Demographic comparison between two breed groups of 600 extreme brachycephalic (Bulldog, French Bulldog, Pug) and 600 moderate and non-brachycephalic dogs (moderate: Yorkshire Terrier, non-brachycephalic: Border Terrier and West Highland White Terrier) attending primary-care veterinary practices in England (200 dogs of each breed type)

Sex/neuter

Female entire

236 (40.0)

160 (26.7)

396 (33.3)

<0.001

Female neutered

43 (7.3)

115 (19.2)

158 (13.3)

Male entire

269 (45.6)

211 (35.2)

480 (40.3)

Male neutered

42 (7.1)

114 (19.0)

156 (13.1)

Insured

Insured

103 (17.2)

159 (26.5)

262 (21.8)

<0.001

Not insured

497 (82.8)

441 (73.5)

938 (78.2)

Bodyweight (kg): Median (IQR^a, range)

12.4 (9.5–24.2, 1.6–41.0)

8.7 (5.9–10.5, 1.5–20.7)

9.7 (7.6–12.2, 1.5–41.0)

<0.001

Age (years) at final EPR^b: Median (IQR^a, range)

1.5 (0.4–3.5, 0.0–14.0)

5.5 (2.5–10.2, 0.0–18.2)

3.1 (1.0–7.1, 0.0–18.2)

<0.001

Time in study (years): Median (IQR^a, range)

0.2 (0.0–1.1, 0.0–4.3)

0.9 (0.0–2.4, 0.0–5.0)

0.4 (0.0–1.8, 0.0–5.0)

<0.001