Table 3.
Adjusted hazard ratios for herd-level PCVAD status based on classification of easting into four zones§.
| Variable | Estimate (HR) | 95% CI | P | |
|---|---|---|---|---|
| <500 km East (zone 1) | referent | - | - | - |
| 500 to <600 km East (zone 2) | 1.58 | 1.16, | 2.15 | 0.003 |
| 600 to <700 km East (zone 3) | 0.77 | 0.19, | 3.21 | 0.724 |
| >700 km East (zone 4) | 4.29 | 1.51, | 12.18 | 0.006 |
| PRRSv status (positive) | 1.58 | 0.92, | 2.73 | 0.097 |
| LR χ2 = 15.68, df = 4, n = 278, P = 0.0035, AIC = 1732.9 | ||||
| No GOF test could be produced for the model with categorical data Global test of proportional hazard assumption (χ2 = 1.69, df = 4, P = 0.79) | ||||
§The table corresponds to survival curves in Figure 5