Table 3. Multivariable logistic regression results of risk factors for race-day fatality in British flat racing Thoroughbreds (2000 to 2013), including a random effect for trainer (P = 0.01).
| Variable | Level | No. of Cases |
No. of Starts |
Incidence/ 1000 starts |
Odds Ratio (95% Confidence Interval) |
Wald P value | Likelihood Ratio P Value |
|---|---|---|---|---|---|---|---|
| Course-level variables | |||||||
| Surface | Turf | 377 | 548,571 | 0.69 | 1 | 0.001 | |
| All-weather | 233 | 258,193 | 0.90 | 1.52 (1.19–1.95) | 0.001 | ||
| Going | Hard or Firm | 25 | 29,294 | 0.85 | 1.40 (0.90–2.16) | 0.13 | 0.006 |
| Good to firm, Standard to fast | 179 | 220,379 | 0.81 | 1.29 (1.02–1.63) | 0.04 | ||
| Good, Standard | 317 | 394,225 | 0.80 | 1 | |||
| Good to soft, Standard to slow | 46 | 84,371 | 0.55 | 0.81 (0.58–1.14) | 0.23 | ||
| Soft, heavy or slow | 43 | 78,495 | 0.55 | 0.80 (0.56–1.14) | 0.21 | ||
| Race-level variables | |||||||
| Distance (per 100 metres) | 1.05 (1.03–1.06) | <0.001 | <0.001 | ||||
| Year | 2000 | 31 | 48,932 | 0.63 | 0.65 (0.41–1.02) | 0.06 | 0.03 |
| 2001 | 38 | 53,239 | 0.71 | 0.77 (0.50–1.17) | 0.22 | ||
| 2002 | 58 | 52,999 | 1.09 | 1.24 (0.85–1.82) | 0.26 | ||
| 2003 | 30 | 52,919 | 0.57 | 0.64 (0.41–1.01) | 0.06 | ||
| 2004 | 44 | 58,778 | 0.75 | 0.91 (0.61–1.37) | 0.66 | ||
| 2005 | 40 | 60,090 | 0.67 | 0.81 (0.54–1.23) | 0.33 | ||
| 2006 | 32 | 59,242 | 0.54 | 0.63 (0.41–0.99) | 0.04 | ||
| 2007 | 42 | 60,078 | 0.70 | 0.82 (0.54–1.23) | 0.33 | ||
| 2008 | 44 | 61,998 | 0.71 | 0.83 (0.56–1.25) | 0.38 | ||
| 2009 | 51 | 61,968 | 0.82 | 0.94 (0.64–1.39) | 0.76 | ||
| 2010 | 58 | 60,816 | 0.95 | 1.10 (0.75–1.60) | 0.62 | ||
| 2011 | 38 | 59,592 | 0.64 | 0.73 (0.48–1.12) | 0.15 | ||
| 2012 | 53 | 58,593 | 0.90 | 1.07 (0.73–1.57) | 0.73 | ||
| 2013 | 51 | 57,520 | 0.89 | 1 | |||
| Season | Spring | 120 | 186,632 | 0.64 | 1 | 0.01 | |
| Summer | 240 | 311,753 | 0.77 | 1.25 (0.99–1.57) | 0.05 | ||
| Autumn | 176 | 207,788 | 0.85 | 1.36 (1.07–1.74) | 0.01 | ||
| Winter | 74 | 100,591 | 0.74 | 0.89 (0.65–1.23) | 0.48 | ||
| Auction race | No | 560 | 753,179 | 0.74 | 1 | 0.03 | |
| Yes | 50 | 53,585 | 0.93 | 1.46 (1.06–2.01) | 0.02 | ||
| Horse-level variables | |||||||
| Current age (years) | 2 | 101 | 155,367 | 0.65 | 1 | <0.001 | |
| 3 | 186 | 254,906 | 0.73 | 1.73 (1.27–2.34) | <0.001 | ||
| 4 | 98 | 154,099 | 0.64 | 1.96 (1.33–2.89) | 0.001 | ||
| 5 | 81 | 94,093 | 0.86 | 3.06 (2.02–4.64) | <0.001 | ||
| 6 | 49 | 60,662 | 0.81 | 3.24 (2.03–5.19) | <0.001 | ||
| 7+ | 95 | 87,637 | 1.08 | 5.11 (3.24–8.05) | <0.001 | ||
| First year racing | No | 413 | 583,391 | 0.71 | 1 | <0.001 | |
| Yes | 197 | 223,373 | 0.88 | 2.16 (1.66–2.80) | <0.001 | ||
| Number of previous flat starts | 0.98 (0.98–0.99) | <0.001 | <0.001 | ||||
| Eye cover | No | 517 | 701,796 | 0.74 | 1 | 0.01 | |
| Yes, first time | 28 | 20,654 | 1.36 | 1.83 (1.25–2.69) | <0.001 | ||
| Yes, worn previously | 65 | 84,314 | 0.77 | 1.18 (0.90–1.54) | 0.23 | ||
| Horse average performance score | 1.02 (1.005–1.04) | 0.01 | 0.01 | ||||