Table 3.
Adjusted odds ratios of patient-to-intensivist ratio with hospital mortality across patient subgroups
| p value for interaction term in full broad cohort model | 1st PIR spline term, OR (95% CI) |
2nd PIR spline term, OR (95% CI) |
3rd PIR spline term, OR (95% CI) |
p value for Wald testing for PIR spline terms within subgroups | |
|---|---|---|---|---|---|
| ICU size in tertiles (beds) | 0.037 | ||||
| ≤ 13 | 0.99 (0.92, 1.07) | 1.1 (0.84, 1.44) | 0.67 (0.28, 1.65) | 0.66 | |
| 13–22 | 1.02 (0.93, 1.12) | 0.98 (0.75, 1.28) | 1.02 (0.45, 2.29) | 0.82 | |
| ≥ 23 | Model did not converge | ||||
| Patient type | 0.039 | ||||
| Medical | 1.04 (0.97, 1.12) | 0.87 (0.69, 1.1) | 1.46 (0.7, 3.04) | 0.37 | |
| Non-cardiac surgical | 0.98 (0.92, 1.04) | 1.13 (0.93, 1.37) | 0.67 (0.37, 1.2) | 0.45 | |
| Cardiac surgical | 0.94 (0.73, 1.22) | 1.71 (0.73, 4.04) | 0.12 (0.01, 2.04) | 0.23 | |
| Mechanical ventilation | 0.1 | ||||
| No | 1.08 (1.01, 1.16) | 0.85 (0.68, 1.06) | 1.48 (0.75, 2.93) | 0.07 | |
| Yes | 0.98 (0.93, 1.04) | 1.11 (0.91, 1.34) | 0.72 (0.4, 1.31) | 0.47 | |
| Sepsis | 0.17 | ||||
| No | 1.02 (0.97, 1.07) | 0.98 (0.84, 1.15) | 1.02 (0.62, 1.68) | 0.63 | |
| Yes | Model did not converge | ||||
| Time of admission | 0.58 | ||||
| Daytime (7a–6:59p) | 1.02 (0.97, 1.08) | 1.02 (0.85, 1.22) | 0.88 (0.5, 1.55) | 0.15 | |
| Overnight (7p–6:59a) | 1.04 (0.97, 1.11) | 0.93 (0.75, 1.16) | 1.2 (0.61, 2.35) | 0.52 | |
| ANZROD probability of death quartiles | < 0.001 | ||||
| Q1 (≤ 0.6%) | 1.38 (0.83, 2.29) | 0.33 (0.07, 1.5) | 28.57 (0.31, 2655.34) | 0.51 | |
| Q2 (0.6–1.8%) | 1.08 (0.87, 1.34) | 0.64 (0.32, 1.28) | 4.18 (0.49, 35.35) | 0.22 | |
| Q3 (1.9–6.4%) | 1.04 (0.93, 1.15) | 0.93 (0.66, 1.32) | 1.17 (0.4, 3.41) | 0.85 | |
| Q4 (≥ 6.5%) | 1.01 (0.96, 1.06) | 1.05 (0.9, 1.24) | 0.8 (0.48, 1.32) | 0.11 | |
| ICU LOS quartiles | < 0.001 | ||||
| Q1 (≤ 0.9 days) | 1.15 (1, 1.32) | 0.69 (0.44, 1.09) | 2.76 (0.68, 11.2) | 0.29 | |
| Q2 (1.0–1.8 days) | 1.02 (0.9, 1.16) | 0.98 (0.65, 1.47) | 1.02 (0.29, 3.57) | 0.97 | |
| Q3 (1.9–3.4 days) | 1.1 (1, 1.21) | 0.77 (0.57, 1.04) | 2.08 (0.82, 5.27) | 0.24 | |
| Q4 (≥ 3.5 days) | 0.99 (0.94, 1.05) | 1.11 (0.91, 1.35) | 0.69 (0.38, 1.27) | 0.13 | |
All models are Model 3 (including patient, intensivist staffing, and non-intensivist staffing characteristics)
CI confidence interval, ICU intensive care unit, LOS length of stay, OR odds ratio, PIR patient-to-intensivist ratio, Q quartile