Nurse staffi ng and education and hospital mortality in nine European countries: a retrospective observational study

Background Austerity measures and health-system redesign to minimise hospital expenditures risk adversely aff ecting patient outcomes. The RN4CAST study was designed to inform decision making about nursing, one of the largest components of hospital operating expenses. We aimed to assess whether diff erences in patient to nurse ratios and nurses ’ educational qualifi cations in nine of the 12 RN4CAST countries with similar patient discharge data were associated with variation in hospital mortality after common surgical procedures. Methods For this observational study, we obtained discharge data for 422 730 patients aged 50 years or older who underwent common surgeries in 300 hospitals in nine European countries. Administrative data were coded with a standard protocol (variants of the ninth or tenth versions of the International Classifi cation of Diseases) to estimate 30 day in-hospital mortality by use of risk adjustment measures including age, sex, admission type, 43 dummy variables suggesting surgery type, and 17 dummy variables suggesting comorbidities present at admission. Surveys of 26 516 nurses practising in study hospitals were used to measure nurse staffi ng and nurse education. We used generalised estimating equations to assess the eff ects of nursing factors on the likelihood of surgical patients dying within 30 days of admission, before and after adjusting for other hospital and patient characteristics. Findings An increase in a nurses ’ workload by one patient increased the likelihood of an inpatient dying within 30 days of admission by 7 % (odds ratio 1·068, 95 % CI 1·031–1·106), and every 10 % increase in bachelor’s degre