Negative binomial regression results for models 1–3 (n=468, 26 counties, 6 age groups, 3 years)
| Factor (standardised) | Model 1 (M1)/univariate1
Pearson χ²=1.039 α =0.05 | Model 2 (M2) Pearson χ²=1.005 α =0.04 | Model 3 (M3) Pearson χ²=1.029 α =0.027 | |||
| IRR (95% CI) | P values | IRR (95% CI) | P values | IRR (95% CI) | P values | |
| Age 1 (0–19) | 1.00 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 |
| Age 2 (20–44) | 1.35 (1.23 to 1.48) | 0.52 (0.31 to 0.89) | 0.86 (0.54 to 1.37) | |||
| Age 3 (45–54) | 2.10 (1.89 to 2.33) | 1.11 (0.77 to 1.62) | 1.79 (1.31 to 2.45) | |||
| Age 4 (55–64) | 3.03 (2.78 to 3.30) | 1.33 (0.83 to 2.14) | 2.63 (1.78 to 3.87) | |||
| Age 5 (65–74) | 5.22 (4.79 to 5.69) | 3.98 (3.27 to 4.84) | 5.26 (4.07 to 6.79) | |||
| Age 6 (75+) | 15.21 (13.94 to 16.59) | 15.22 (13.95 to 16.59) | 14.79 (7.94 to 27.54) | |||
| Percentage of population unemployed | 1.50 (1.26 to 1.78) | <0.001 | 1.47 (1.20 to 1.81) | 0.003 | 1.24 (1.04 to 1.41) | 0.018 |
| Percentage of the population living in rural areas | 1.04 (0.96 to 1.12) | 0.348 | 1.02 (0.95 to 1.09) | 0.597 | 0.97 (0.91 to 1.03) | 0.295 |
| Conversion rate of emergency department presentations to admissions | 0.98 (0.93 to 1.04) | 0.471 | ||||
| Percentage of emergency admissions with length of stay equal to 1 | 1.19 (1.08 to 1.30) | <0.001 | 1.20 (1.11 to 1.30) | <0.001 | ||
| Number of general practitioners per 100 000 | 0.97 (0.91 to 1.04) | 0.430 | 1.01 (0.96 to 1.05) | 0.801 | ||
| Percentage of the population eligible for the General Medical Services card | 1.40 (1.13 to 1.74) | 0.002 | 1.24 (0.98 to 1.57) | 0.07 | ||
| Percentage of population with private health insurance | 0.902 (0.87 to 0.93) | <0.001 | 0.92 (0.89 to 0.96) | <0.001 | ||
All models are age-adjusted. Results for age, model and based on age-only model (M1).
The quoted IRR represents the incidence rate ratio associated with a 1 SD change in the risk factor.