Table 3.
Hazard Ratios and Confidence Intervals for Concomitant Medical Conditions and Any Cause or Preventable‡ Crashes
| Number of Conditions | Hazard Ratio | 95% Confidence Interval | Hazard Ratio | 95% Confidence Interval | |||
|---|---|---|---|---|---|---|---|
| Crash of Any severity | Preventable‡ Crash of Any Severity | ||||||
| Unadjusted | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 0.94 | 0.90 | 0.98 | 0.93 | 0.89 | 0.97 | |
| 2 | 0.92 | 0.84 | 1.01 | 0.89 | 0.80 | 1.00 | |
| 3 | 1.15 | 0.71 | 1.87 | 1.00 | 0.60 | 1.65 | |
| 4 or more | 3.63 | 3.51 | 3.76 | N/A | |||
| Model 1* | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 1.02 | 0.96 | 1.09 | 1.03 | 0.95 | 1.12 | |
| 2 | 1.01 | 0.91 | 1.13 | 1.01 | 0.89 | 1.15 | |
| 3 | 1.27 | 0.79 | 2.06 | 1.13 | 0.69 | 1.87 | |
| 4 or more | 4.16 | 3.85 | 4.51 | N/A | |||
| Model 2† | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 1.03 | 0.92 | 1.15 | 1.05 | 0.93 | 1.19 | |
| 2 | 1.08 | 0.91 | 1.3 | 1.11 | 0.90 | 1.35 | |
| 3 | 1.32 | 0.84 | 2.1 | 0.98 | 0.62 | 1.53 | |
| 4 or more | 2.01 | 1.72 | 2.34 | N/A | |||
| DOT Reportable Crash | Preventable‡ DOT Reportable Crash | ||||||
| Unadjusted | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 0.85 | 0.75 | 0.96 | 0.89 | 0.77 | 1.04 | |
| 2 | 0.97 | 0.76 | 1.24 | 0.9 | 0.55 | 1.47 | |
| 3 | 2.79 | 1.63 | 4.74 | 1.73 | 1.46 | 2.04 | |
| 4 or more | 1.78 | 1.58 | 2.01 | N/A | |||
| Model 1* | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 0.83 | 0.65 | 1.05 | 1.06 | 0.82 | 1.39 | |
| 2 | 0.94 | 0.67 | 1.32 | 1.11 | 0.63 | 1.93 | |
| 3 | 2.63 | 1.49 | 4.89 | 2.15 | 1.54 | 3.01 | |
| 4 or more | 1.72 | 1.30 | 2.29 | N/A | |||
| Model 2† | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 0.73 | 0.43 | 1.23 | 1.12 | 0.84 | 1.49 | |
| 2 | 0.97 | 0.53 | 1.75 | 1.2 | 0.66 | 2.20 | |
| 3 | 2.55 | 1.37 | 4.73 | 2.53 | 1.65 | 3.88 | |
| 4 or more | 1.62 | 0.91 | 3.11 | N/A | |||
| DOT Reportable Crash with Injuries | Preventable‡ DOT Reportable Crash with Injuries | ||||||
| Unadjusted | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 0.86 | 0.66 | 1.11 | 0.96 | 0.70 | 1.32 | |
| 2 | 0.97 | 0.61 | 1.55 | 0.94 | 0.46 | 1.89 | |
| 3 or more | 3.36 | 1.43 | 7.91 | 2.01 | 1.41 | 2.83 | |
| Model 1* | 0 | 1.00 | Reference | 1.00 | Reference | ||
| 1 | 0.78 | 0.46 | 1.32 | 1.01 | 0.47 | 2.15 | |
| 2 | 0.89 | 0.45 | 1.77 | 1.01 | 0.38 | 2.65 | |
| 3 or more | 3.21 | 1.17 | 8.75 | 2.23 | 1.09 | 5.31 | |
*
Adjusted for Age, Gender and BMI
†
Adjusted for Age, Gender, BMI, Certification Length, Drug Use, Drug Test, Muscular Disease, Seatbelt Use, Seizure History and Speed
N/A- Not available, there were not enough preventable crashes to create a stable estimate for 4 or more medical conditions.
‡
Preventable crashes are those identified as being preventable by the company’s crash investigation team