Table 2 Multivariable model results displaying the association for drug groups (A) and individual drugs (B)

Age

< 0.001

< 0.001

1 to 4 years

Reference

Reference

 > 4 to 8 years

0.84 (0.72–0.97)

0.019

0.84 (0.73–0.96)

0.013

 > 8 years

0.5 (0.42–0.6)

< 0.001

0.53 (0.45–0.63)

< 0.001

 Male

Reference

Reference

 Female

0.96 (0.83–1.1)

0.535

0.95 (0.83–1.09)

0.453

 Neutered

Reference

Reference

 Entire

0.64 (0.52–0.78)

< 0.001

0.66 (0.54–0.81)

< 0.001

Breeds

< 0.001

< 0.001

 Small

Reference

Reference

 Medium

0.53 (0.43–0.64)

< 0.001

0.53 (0.43–0.64)

< 0.001

 Large

0.46 (0.39–0.55)

< 0.001

0.48 (0.4–0.56)

< 0.001

Evidence of concurrent skin infection at baseline

< 0.001

< 0.001

 Non-infectious allergic dermatitis

Reference

Reference

 No evidence of concurrent skin infection

0.73 (0.5–1.06)

0.094

0.74 (0.52–1.06)

0.099

 Superficial pyoderma

2.71 (1.89–3.89)

< 0.001

2.58 (1.81–3.68)

< 0.001

 Deep pyoderma

Omitted

Omitted

Infectious agents in ear at baseline

0.073

0.16

 No infectious agents present

Reference

Reference

 Cocci present

0.99 (0.65–1.51)

0.965

0.91 (0.59–1.41)

0.687

 Rods present

0.53 (0.18–1.55)

0.248

0.52 (0.17–1.56)

0.244

 Malassezia present

1.31 (1.02–1.69)

0.035

1.23 (0.98–1.56)

0.076

 Topical glucocorticoids

0.78 (0.62–0.98)

0.034

 Systemic glucocorticoids

0.5 (0.39–0.64)

0

 Antihistamines

0.48 (0.31–0.74)

0.001

 Allergy testing (yes/no)

3.94 (1.27–12.18)

0.017

 Hypoallergenic diet

1.77 (1.26–2.47)

0.001

 Medicated shampoo

0.69 (0.51–0.92)

0.011

 Cefovecin

0.62 (0.39–0.98)

0.043

 Chlorhexidine (2–5%)

0.57 (0.42–0.77)

< 0.001

 Neomycin

0.4 (0.28–0.56)

< 0.001

 Amoxycillin plus clavulanic acid

0.55 (0.39–0.78)

0.001