Table 2.
Univariable incidence rate ratios (IRR) and 95% confidence of a suspected cardiac failure occurring with the effects of the recording system, number of participants, track surface, horse age, horse sex and race distance for Thoroughbred flat racing in the 2011/12–2021/22 seasons.
| Univariable | Cardiac n (%) |
Starts | IRR [95% CI] | p-Value | Wald p-Value |
|---|---|---|---|---|---|
| Recording system | |||||
| Local veterinary clinic | 10 (31.3%) | 91,028 | (Referent) | 0.530 | |
| Contracted veterinarian | 17 (53.1%) | 135,545 | 1.1 [0.5–2.6] | 0.747 | |
| Online system | 5 (15.6%) | 70,720 | 0.6 [0.2–1.8] | 0.416 | |
| Number of starters | |||||
| Less than nine | 4 (12.5%) | 47,123 | (Referent) | 0.607 | |
| Nine or more | 28 (87.5%) | 250,170 | 1.3 [0.5–4.4] | ||
| Track condition/surface | |||||
| Firm (Turf) | 0 (%) | 7752 | - | ||
| Good (Turf) | 16 (50%) | 126,852 | (Referent) | 0.693 | |
| Soft (Turf) | 8 (25%) | 90,985 | 0.9 [0.4–2.1] | 0.838 | |
| Heavy (Turf) | 8 (25%) | 69,288 | 0.7 [0.3–1.6] | 0.405 | |
| Synthetic | 0 (0%) | 2180 | - | ||
| Horse age | |||||
| Under five years | 11 (34.4%) | 157,361 | (Referent) | 0.040 | |
| Five years and over | 21 (65.6%) | 139,932 | 2.1 [1.1–4.6] | ||
| Horse sex | |||||
| Male (Colt, gelding stallion) | 16 (50.0%) | 153,981 | 0.9 [0.5–1.9] | ||
| Female (Filly or mare) | 16 (50.0%) | 143,312 | (Referent) | 0.840 | |
| Race distance | |||||
| Sprint (≤1400 m) | 15 (46.9%) | 160,096 | 1.3 [0.4–8.3] | 0.723 | |
| Mile (1401–1799 m) | 8 (25.0%) | 70,350 | 1.6 [0.4–1.1] | 0.560 | |
| Middle distance (1800–2099 m) | 2 (6.3%) | 27,877 | (Referent) | 0.490 | |
| Staying (≥2100 m) | 7 (21.9%) | 38,970 | 2.5 [0.6–1.7] | 0.252 | |
| Weight carried (kg) | |||||
| <54 | 4 (12.5%) | 32,879 | (Referent) | 0.766 | |
| 54–<56 | 7 (21.9%) | 87,878 | 0.7 [0.2–2.5] | 0.499 | |
| 56–<58 | 14 (43.8%) | 108,588 | 1.1 [0.4–3.7] | 0.918 | |
| ≥58 | 7 (21.9%) | 67,438 | 0.9 [0.3–3.3] | 0.800 | |
| Jockey experience | |||||
| Apprentice | 10 (33.3%) | 84,394 | (Referent) | 0.720 | |
| Jockey | 22 (66.7%) | 212,901 | 0.9 [0.4–1.9] |