Patient level (mortality, unplanned ICU and length of stay) outcomes: comparing proportional change from Time 0 between the intervention and control group at Time 1 and Time 2
| Group | Time 0 | Time 1 | Time 1 vs Time 0* | Time 2 | Time 2 vs Time 0* | P value† |
| Mortality | ||||||
| n (%) | n (%) | Adjusted OR (95% CI)‡ | n (%) | Adjusted OR (95% CI)‡ | ||
| Both | 60 (3.2) | 66 (3.1) | 1.06 (0.75 to 1.49) | 61 (3.0) | 0.96 (0.68 to 1.37) | 0.809 |
| Intervention | 23 (2.4) | 33 (3.0) | 1.33 (0.87to 2.02) | 32 (3.1) | 1.35 (0.90 to 2.01) | 0.250 |
| Control | 37 (4.0) | 33 (3.2) | 0.88 (0.53 to 1.44) | 29 (2.9) | 0.70 (0.46 to 1.07) | 0.116 |
| Time 1 vs Time 0 OR (95% CI)§ | Time 2 vs Time 0 OR (95% CI)§ | |||||
| 1.63 (0.82 o 3.24) | 1.89 (1.05 o 3.38) | 0.102¶ | ||||
| p=0.166 | p=0.033 | |||||
| Unplanned ICU admission | ||||||
| n (%) | n (%) | Adjusted OR (95% CI)‡ | n (%) | Adjusted OR (95% CI)‡ | ||
| Both | 78 (4.1) | 71 (3.3) | 0.93 (0.68 to 1.23) | 77 (3.8) | 1.03 (0.76 to 1.39) | 0.856 |
| Intervention | 33 (3.5) | 36 (3.5) | 1.13 (0.70 to 1.85) | 30 (2.9) | 1.02 (0.68 to 1.51) | 0.873 |
| Control | 45 (4.9) | 35 (3.2) | 0.79 (0.48 to 1.30) | 47 (4.7) | 1.03 (0.64 to 1.66) | 0.582 |
| Time 1 vs Time 0 OR (95% CI)§ | Time 2 vs Time 0 OR (95% CI)§ | |||||
| 1.43 (0.74 to 2.76) | 0.99 (0.56 to 1.78) | 0.528¶ | ||||
| p=0.294 | p=0.992 | |||||
| Hospital length of stay** | ||||||
| Mean (SD) | Mean (SD) | Adjusted mean difference (95% CI)‡ | Mean (SD) | Adjusted mean difference (95% CI)‡ | ||
| Both | 13.40 (20.99) | 10.52 (13.96) | −1.18 (–1.86 to –0.51) | 12.71 (18.00) | 0.53 (–0.15 to 1.21) | <0.001 |
| Intervention | 13.61 (24.37) | 10.32 (14.62) | −1.31 (–2.18 to –0.45) | 11.40 (16.41) | −0.17 (–1.04 to 0.71) | 0.005 |
| Control | 13.18 (16.76) | 10.74 (13.24) | −0.91 (–1.87 to 0.06) | 14.06 (19.47) | 1.51 (0.54 to 2.49) | <0.001 |
| Intervention vs control differential change (Time 1 vs Time 0) Mean (95% CI)§ | Intervention vs control differential change (Time 2 vs Time 0) Mean (95% CI)§ | |||||
| −1.10 (–2.44 to 0.24) | −2.18 (–3.53 to –0.82) | 0.007¶ | ||||
| p=0.106 | p=0.002 | |||||
*OR (95% CI) compares within-group difference across follow-ups.
†P value for trend tests the changes in the outcome across time points (T0, T1 and T2) in each study group.
‡Adjusted for age, sex, hospital site, admission type and DRG weight.
§Intervention effect: OR (95% CI) (mortality, unplanned ICU and mean LOS) comparing changes over time from T0 between intervention and control at Time 1 and Time 2. Ratio of OR estimated from two-way interaction between time points and intervention group from a GEE model that included audit time point and intervention group as factors and the two-way interaction between time points and intervention group and adjusting for age, sex, hospital site, admission type and DRG weight; intervention vs control. Mean LOS estimated from two-way interaction between time points and intervention group from a GEE model with same adjustments as for mortality and unplanned ICU admissions.
¶Simultaneously testing intervention effect across T1 and T2 using a likelihood ratio test with 2 degrees of freedom.
**Missing hospital length of stay data (0.8%) were imputed using mean for study group (intervention or control) and time (T0, T1, T2).
DRG, Diagnosis-Related Group; GEE, generalised estimating equations; ICU, intensive care unit; LOS, length of stay.