Table 3

Hazard of death associated with cumulative hours above or below the mean during the first 5 days (linear and non-linear models)

Staffing exposure
(cumulative sum over the first 5 days)
Adjusted HRP values95% CI
Linear model
 RN hours0.970.0230.94 to 1.00
 NA hours1.010.3940.98 to 1.04
Df 41; AIC 61 919.4; BIC 42 405.66
Non-linear model
 RN hours0.980.2000.95 to 1.01
 RN hours2 1.000.6210.99 to 1.01
 RN hours3 1.000.9301.00 to 1.00
 NA hours1.000.8350.97 to 1.04
 NA hours2 1.010.0141.00 to 1.02
 NA hours3 1.000.0611.00 to 1.00
  • Df 45; AIC 61 920.19; BIC 62 453.88.

  • All models include control for turnover (admissions per nurse), patient risk (SHMI), first NEWS, emergency admission and ward (for full model see online supplementary tables g,h).

  • AIC, Akaike information criterion; BIC, Bayesian information criterion; NA, nursing assistant; NEWS, National Early Warning Score; RN, registered nurse; SHMI, Summary Hospital Mortality Indicator.