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Fewer patients die with more nurses on ward

It’s unwise to keep substituting nurses with healthcare support workers, shows research

Louise Prime

Wednesday, 10 February 2016

Inpatient mortality rates are a fifth lower when there are six or fewer patients per registered nurse than when there are more than 10 per nurse, research in hospitals in England has found. Authors of the study*, published today in BMJ Open, called for a review of current policies that lead to healthcare support workers partly replacing registered nurses.

Researchers led from the University of Southampton compared risk-adjusted mortality rates for adult inpatients across hospitals in England. They analysed administrative data from 137 NHS acute hospital trusts (overall staffing, measured as beds per registered nurse, doctor, and healthcare support worker); and also conducted a cross-sectional survey of 2,917 registered nurses in a subsample of 31 trusts (looking at number of patients per ward nurse). They found substantial variation between trusts in medical and nurse staffing – with a more than fourfold variation in registered nurse staffing between the lowest- and highest-staffed hospital trust.

Overall, in hospitals where each registered nurse had fewer patients to care for on average, the mortality rate was lower than in hospitals where each nurse was caring for more patients, even after adjusting for influential factors such as age, comorbidity and number of emergency admissions during the previous 12 months.

For medical admissions, trusts with a mean of six or fewer patients per registered nurse had a 20% lower mortality rate compared with trusts with more than 10 patients per registered nurse; for surgical admissions, mortality was 17% lower when there were six or patients per nurse than when there were more than 10. On the other hand, inpatient mortality rates tended to rise as the number of healthcare support workers increased.

The authors said that as their study was observational, they couldn’t prove cause and effect, nor could they identify “safe staffing levels”. But they suggested: “Given the overall strength of evidence for an association, it does seem feasible to identify staffing levels where risk to patients is likely to be increased.”

They warned that as financial pressure increases and the population ages, there is a growing tendency to substitute registered nurses with less well trained staff nurses – but that this might be unwise.

They concluded: “When determining the safety of nurse staffing on hospital wards, the level of registered nurse staffing is crucial, and there is no evidence to suggest that higher levels of healthcare support worker staffing have a role in reducing mortality rates. Current policies geared towards substituting [these] workers for registered nurses should be reviewed in the light of this evidence.”

* Griffiths P, et al. Registered nurse, healthcare support worker, medical staffing levels and mortality in English hospital trusts: a cross-sectional study. BMJ Open 2016; 6: e008751. doi:10.1136/bmjopen-2015008751.

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