Unadjusted and adjusted IRR of an interaction with any member of staff
| Characteristic | Univariate IRR (95% CI) | Adjusted for all predictors* Adjusted IRR (95% CI) |
| Patient characteristics | ||
| Age (per unit increase) | 1.01 (1.00 to 1.01) | 1.00 (1.00 to 1.01) |
| Male | 0.99 (0.85 to 1.14) | 0.98 (0.84 to 1.14) |
| With dementia | 1.02 (0.89 to 1.17) | 1.01 (0.88 to 1.16) |
| Observation session characteristics | ||
| Number of patients per RN | (p=0.331) | (p=0.035) |
| ≤6 | 1.03 (0.89, 1.18) | 1.20 (1.01, 1.43) |
| >6 to <8 (reference) | 1.00 | 1.00 |
| ≥8 | 1.13 (0.96, 1.32) | 1.21 (1.03, 1.43) |
| Number of patients per HCA | (p=0.000) | (p=0.001) |
| <7 | 1.02 (0.89, 1.18) | 0.97 (0.83, 1.13) |
| 7 to 8 (reference) | 1.00 | 1.00 |
| >8 | 0.76 (0.65, 0.88) | 0.75 (0.64, 0.88) |
| Ward | ||
| A (reference) | 1.00 | 1.00 |
| B | 1.31 (1.08 to 1.59) | 1.37 (1.08 to 1.72) |
| C | 0.86 (0.70 to 1.05) | 0.86 (0.67 to 1.09) |
| D | 1.12 (0.91 to 1.37) | 1.07 (0.86 to 1.34) |
| E | 0.93 (0.76 to 1.14) | 0.89 (0.71 to 1.13 |
| F | 0.84 (0.68 to 1.03) | 0.93 (0.75 to 1.15) |
Patient level analysis (n=270).
*Observation session included as a random effect.
HCA, healthcare assistant; IRR, incidence rate ratios; RN, registered nurse.