Outcomes of variation in hospital nurse staffing in English hospitals: Cross-sectional analysis of survey data and discharge records

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Abstract

Context

Despite growing evidence in the US, little evidence has been available to evaluate whether internationally, hospitals in which nurses care for fewer patients have better outcomes in terms of patient survival and nurse retention.

Objectives

To examine the effects of hospital-wide nurse staffing levels (patient-to-nurse ratios) on patient mortality, failure to rescue (mortality risk for patients with complicated stays) and nurse job dissatisfaction, burnout and nurse-rated quality of care.

Design and setting

Cross-sectional analysis combining nurse survey data with discharge abstracts.

Participants

Nurses (N=3984) and general, orthopaedic, and vascular surgery patients (N=118752) in 30 English acute trusts.

Results

Patients and nurses in the quartile of hospitals with the most favourable staffing levels (the lowest patient-to-nurse ratios) had consistently better outcomes than those in hospitals with less favourable staffing. Patients in the hospitals with the highest patient to nurse ratios had 26% higher mortality (95% CI: 12–49%); the nurses in those hospitals were approximately twice as likely to be dissatisfied with their jobs, to show high burnout levels, and to report low or deteriorating quality of care on their wards and hospitals.

Conclusions

Nurse staffing levels in NHS hospitals appear to have the same impact on patient outcomes and factors influencing nurse retention as have been found in the USA.

Section snippets

What is already known about the topic?

  • There is growing evidence from studies in the US that hospitals in which nurses care for fewer patients have better patient outcomes, but there is little evidence available internationally.

What this paper adds

  • This large-scale national study of nurse staffing in the UK supports US findings that patients and nurses in hospitals with the most favourable staffing levels have better outcomes than those in less favourably staffed hospitals.

  • Provides evidence that the positive relationship between low nurse: patient staffing ratios and favourable patient and nurse outcomes is an international phenomenon.

Outcomes of variation in hospital nurse staffing in English hospitals

The impact of nurse staffing on patient outcomes has been controversial in the US and as contentious in the UK. A 2001 Audit Commission report on ward staffing in National Health Service (NHS) hospitals noted considerable variation across trusts in expenditures on nurse staffing but was not able to determine whether those differences were associated with variation in patient outcomes (Audit Commission, 2001). The Commission concluded, “Unless and until trusts that spend more [on staffing] can

Methods

Nurse and patient data from 30 English hospital trusts analysed in this paper were collected in connection with the International Hospital Outcomes Study begun in 1999. The theoretical background and methods for the study are discussed elsewhere (Aiken et al., 2001; Aiken et al., 2002a, Aiken et al., 2002b; Estabrooks et al., 2005). Data were gathered from three sources. Information about hospital structure (such as size and teaching status) came from administrative databases. Nurses practicing

Results

Across the 30 hospitals, 3984 nurses responded to the questionnaire, most of whom were registered nurses. As noted in Table 2, two-thirds were employed on medical-surgical units, 1 in 10 worked in an intensive care unit, and nearly 1 in 4 worked in another clinical area (accident and emergency, elderly, and an “other” category were the three most common of these). Slightly more than one-third of the nurses experienced high burnout and were dissatisfied with their jobs (36% each). Some 16%

Discussion

In this study of 30 hospital trusts in England, we found a large and consistent effect of nurse staffing on mortality outcomes in surgical patients as well as on nurse job outcomes and nurse ratings of quality of care. Hospitals in which nurses cared for the fewest patients each had significantly lower surgical mortality and FTR rates compared to those in which nurses cared for the greatest number of patients each. These findings are remarkably similar to those observed in 168 Pennsylvania

Acknowledgements

This research was supported by grants from the Nuffield Trust, the Commonwealth Fund of New York, and the National Institute of Nursing Research, National Institutes of Health (R01NR04513). The authors thank Douglas Sloane, Christine Hancock, James Buchan, and members of the International Hospital Outcomes Consortium for their contributions to this research.

We are grateful to the National Institute for Health and the Commonwealth Fund of New York for supporting the study.

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