Table 2.
Results from Modelling of Hazard for Unplanned Readmissions within 30 Days after Discharge. Cox' Regression Analysis, with Adjustment for Clustering Effects.§ 113,055 Patients Were Included, of these 9,692 Were Readmitted
| Statistics | |||
|---|---|---|---|
| Hazard Ratio | |||
| Variables§§ | (95% CI) | z or(χ2)§§§ | p |
| Hospital practice | |||
| Index of hospital LOS§§§§ | (23.88, 3 df | <0.0001) | |
| 1 | 1.00 | ||
| 2 | 1.10 (1.02, 1.20) | 2.33 | 0.020 |
| 3 | 0.89 (0.81, 0.96) | −2.79 | 0.005 |
| 4 | 0.87 (0.80, 0.94) | −3.34 | 0.001 |
| Staffing ratio§§§§§ | (31.32, 3 df | <0.0001) | |
| 1 | 1.00 | ||
| 2 | 1.14 (1.06, 1.23) | 3.42 | 0.001 |
| 3 | 1.21 (1.12, 1.31) | 4.67 | <0.0001 |
| 4 | 1.00 (0.89, 1.13) | 0.05 | 0.961 |
| Costs per admission | (10.06, 3 df | 0.018) | |
| 1 | 1.00 | ||
| 2 | 1.12 (1.01, 1.25) | 2.16 | 0.031 |
| 3 | 0.98 (0.88, 1.09) | −0.39 | 0.695 |
| 4 | 1.06 (0.96, 1.16) | 1.18 | 0.239 |
| Stand. emerg. admission rate | (6.12, 3 df | 0.106) | |
| 1 | 1.00 | ||
| 2 | 1.00 (0.92, 1.08) | −0.01 | 0.993 |
| 3 | 1.10 (1.01, 1.20) | 2.13 | 0.034 |
| 4 | 1.05 (0.96, 1.15) | 1.02 | 0.310 |
| Specialization of hospital | (2.70, 2 df | 0.259) | |
| Regional | 1.00 | ||
| County | 0.96 (0.89, 1.04) | −1.05 | 0.294 |
| Local | 1.02 (0.94, 1.10) | 0.40 | 0.690 |
| Patient factors | |||
| Age | |||
| 67−80 years | 1.00 | ||
| >80 years | 1.09 (1.02, 1.15) | 2.74 | 0.006 |
| Gender | |||
| Female | 1.00 | ||
| Male | 1.18 (1.14, 1.22) | 8.80 | <0.0001 |
| Type of index admission | |||
| Elective | 1.00 | ||
| Emergent | 1.91 (1.78, 2.05) | 17.94 | <0.0001 |
| Medical or surgical DRG | |||
| Surgical | 1.00 | ||
| Medical | 1.27 (1.17, 1.37) | 5.73 | <0.0001 |
| Cost-weight of the patient's DRG | (246.38, 3 df | <0.0001) | |
| 1 | 1.00 | ||
| 2 | 1.34 (1.25, 1.43) | 8.25 | <0.0001 |
| 3 | 1.61 (1.52, 1.72) | 15.07 | <0.0001 |
| 4 | 1.24 (1.15, 1.33) | 5.78 | <0.0001 |
| Discharge destination | |||
| To another institution | 1.00 | ||
| Home | 1.03 (0.94, 1.13) | 0.62 | 0.534 |
| Living near hospital | |||
| No | 1.00 | ||
| Yes | 1.31 (1.23, 1.40) | 8.16 | <0.0001 |
The summary results of the model were: log likelihood =−111284.4, Wald χ2(23)=2306.7.
For category-variables scaled into four groups, each category represents one quartile of the distribution, see also Table 1. To unify the format of category-variables, those formatted in quartiles were all kept as four categories even if a simplification seems reasonable.
The overall effect of category-variables was tested using repeated (aggregated) tests (χ2).
The index reflects a relative measure of average hospital LOS adjusted for differences in patient-population by way of DRGs and DRG-specific average LOS.
Defined as the annual number of discharges/(man-years of personnel × 365). Adjusted for differences in patient-population by way of DRG and cost-weights.