Hazard of death associated with low staffing levels during the first 5 days (adjusted and unadjusted)
| Staffing exposure (per day over the first 5 days) | HR* | P values | 95% CI | Adjusted HR† | P values | 95% CI |
| RN staffing below ward mean | 1.03 | 0.009 | 1.01 to 1.06 | 1.03 | 0.009 | 1.01 to 1.06 |
| NA staffing below ward mean | 1.04 | <0.001 | 1.02 to 1.07 | 1.04 | <0.001 | 1.02 to 1.07 |
| Admissions per RN >125% of ward mean | 1.05 | 0.024 | 1.01 to 1.09 | 1.05 | 0.024 | 1.01 to 1.09 |
| Admissions per NA >125% of ward mean | 1.00 | 0.873 | 0.96 to 1.04 | 1.00 | 0.873 | 0.96 to 1.04 |
| NEWS on admission | 1.30 | <0.001 | 1.28 to 1.31 | 1.26 | <0.001 | 1.24 to 1.27 |
| SHMI risk score | 1.95 | <0.001 | 1.90 to 2.00 | 1.87 | <0.001 | 1.81 to 1.92 |
| Emergency | 3.89 | <0.001 | 3.16 to 4.79 | 1.24 | 0.085 | 0.97 to 1.60 |
Df 41; AIC 61 889.87; BIC 62 376.13.
Unconditional model adjusting for ward (random effect) only.
Adjusted for ward, SHMI risk score, NEWS on admission and mode of admission (emergency vs elective). For full model see online supplementary table a.
AIC, Akaike information criterion; BIC, Bayesian information criterion; NA, nursing assistant; NEWS, National Early Warning Score; RN, registered nurse; SHMI, Summary Hospital Mortality Indicator.