Effect of the hospital nursing environment on patient mortality: a systematic review

Objective: Research has examined the effect of the structure of health systems on health outcomes, but not how outcomes are affected by the nursing environments in hospitals. Our objective was to gather, critically appraise and synthesize all relevant primary research on the effect of the nursing environment on patient mortality. Methods: Five electronic bibliographic databases were searched from their beginning through to May/June 2001, and Medline and CINAHL were updated to March 2004, using pre-determined search strategies and inclusion criteria. Studies were included if they met pre-determined criteria, reporting primary data both on a hospital environment and patient mortality. Methodological rigour was appraised using accepted criteria for the evaluation of research protocols, including case-mix adjustment. Results: This paper focuses on 27 identified studies that investigated the impact of one or more attributes of the nursing environment on patient mortality. Nineteen studies found an association between one or more unfavourable attributes and higher mortality. There was considerable variability in attribute and outcome measures, settings and research quality across studies. This precluded statistical pooling of results. Conclusions: On balance, current evidence indicates that social and environmental attributes of hospital nursing practice have an effect on the outcomes of care. Before optimal practice settings can be designed, further research of greater rigour is needed to provide a better understanding of the mechanisms that link the nursing environment to patient outcomes.