Table 2 Descriptive and univariable logistic regression results

Purebred status

Crossbred

88 (10.55)

23243 (22.49)

Base

Purebred

746 (89.45)

80109 (77.51)

2.46

1.97–3.07

< 0.001

Common breeds

Crossbreed

88 (10.55)

23241 (22.48)

Base

Pug

55 (6.59)

960 (0.93)

15.13

10.74–21.32

< 0.001

Boxer

69 (8.27)

1317 (1.27)

13.84

10.05–19.06

< 0.001

Shih Tzu

70 (8.39)

1961 (1.90)

9.43

6.86–12.95

< 0.001

Cavalier King Charles Spaniel

58 (6.95)

2274 (2.20)

6.74

4.82–9.41

< 0.001

Bulldog

19 (2.28)

768 (0.74)

6.53

3.96–10.78

< 0.001

King Charles Spaniel

11 (1.32)

485 (0.47)

5.99

3.18–11.28

< 0.001

Lhasa Apso

19 (2.28)

873 (0.84)

5.75

3.48–9.48

< 0.001

French Bulldog

12 (1.44)

630 (0.61)

5.03

2.74–9.24

< 0.001

West Highland White Terrier

28 (3.36)

2831 (2.74)

2.61

1.70–4.00

< 0.001

Staffordshire Bull Terrier

66 (7.91)

6797 (6.57)

2.56

1.86–3.53

< 0.001

Cocker Spaniel

37 (4.44)

4197 (4.06)

2.33

1.58–3.42

< 0.001

English Springer Spaniel

19 (2.28)

2191 (2.12)

2.29

1.39–3.77

0.001

Border Terrier

11 (1.32)

1316 (1.27)

2.21

1.18–4.14

0.014

Chihuahua

17 (2.04)

2206 (2.13)

2.04

1.21–3.43

0.008

Yorkshire Terrier

24 (2.88)

3330 (3.22)

1.90

1.21–2.99

0.005

Jack Russell Terrier

41 (4.92)

6658 (6.44)

1.63

1.12–2.36

0.010

Border Collie

12 (1.44)

2795 (2.70)

1.13

0.62–2.08

0.684

Labrador Retriever

24 (2.88)

9517 (9.20)

0.67

0.42–1.05

0.078

Other purebreds

154 (18.47)

29052 (28.10)

1.40

1.08–1.82

0.012

Kennel Club Breed Groups

Breed not Kennel Club recognised

139 (16.67)

31185 (30.16)

Base

Toy

188 (22.54)

12413 (12.00)

3.40

2.73–4.24

< 0.001

Utility

151 (18.11)

8681 (8.40)

3.90

3.10–4.92

< 0.001

Terrier

120 (14.39)

13537 (13.09)

1.99

1.56–2.54

< 0.001

Gundog

101 (12.11)

20551 (19.88)

1.10

0.85–1.43

0.456

Hound

22 (2.64)

4525 (4.38)

1.09

0.69–1.71

0.706

Pastoral

31 (3.72)

7467 (7.22)

0.93

0.63–1.38

0.721

Working

82 (9.83)

5040 (4.87)

3.65

2.77–4.80

< 0.001

Spaniel-brachycephalic

Crossbred

88 (10.6)

23243 (22.5)

Base

Spaniel

130 (15.6)

9887 (9.6)

3.47

2.65–4.56

< 0.001

Brachycephalic

239 (28.7)

6124 (5.9)

10.31

8.06–13.18

< 0.001

Purebred other

377 (45.2)

64098 (62.0)

1.55

1.23–1.96

< 0.001

Adult (> 9 months) bodyweight (kg)

< 10.0

264 (31.65)

24731 (23.92)

1.63

1.28–2.08

< 0.001

10.0–19.9

245 (29.38)

23047 (22.29)

1.59

1.25–2.03

< 0.001

20.0–29.9

145 (17.39)

18302 (17.70)

1.20

0.92–1.56

0.186

30.0–39.9

88 (10.55)

13301 (12.86)

Base

≥ 40.0

32 (3.84)

6564 (6.35)

0.70

0.46–1.07

0.097

Not available

60 (7.19)

17454 (16.88)

0.58

0.43–0.79

0.001

Bodyweight relative to breed mean

Equal/Higher

389 (46.64)

40713 (39.37)

1.12

0.97–1.29

0.114

Lower

372 (44.60)

43689 (42.25)

Base

Not recorded

73 (8.75)

18997 (18.37)

0.45

0.35–0.58

< 0.001

Age category (years) (pre-existing cases included as not-recorded)

< 3.0

188 (22.54)

33817 (32.71)

Base

3.0–5.9

136 (16.31)

26381 (25.51)

0.93

0.74–1.16

0.504

6.0–8.9

232 (27.82)

20062 (19.40)

2.08

1.71–2.52

< 0.001

9.0–11.9

172 (20.62)

13307 (12.87)

2.33

1.89–2.86

< 0.001

≥ 12.0

106 (12.71)

9633 (9.32)

1.98

1.56–2.51

< 0.001

Not recorded

0 (0.00)

199 (0.19)

~

~

~

Sex

Female

382 (45.80)

49180 (47.68)

Base

Male

452 (54.20)

53933 (52.29)

1.08

0.94–1.24

0.276

Not recorded

0 (0.00)

26 (0.03)

~

~

~

Neuter status

Entire

123 (14.75)

13875 (13.42)

Base

Neutered

436 (52.28)

46050 (44.54)

1.07

0.87–1.31

0.521

Not recorded

275 (32.97)

43474 (42.04)

0.71

0.58–0.88

0.002

Insurance

Non-insured

190 (22.78)

29062 (28.11)

Base

Insured

331 (39.69)

31840 (30.79)

1.59

1.33–1.90

< 0.001

Not recorded

313 (37.53)

42497 (41.10)

1.13

0.94–1.35

0.197