Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Nurse staffing laws in US have ‘not improved patient outcomes’


A law requiring set nurse-to-patient ratios in intensive care units across a US state has not resulted in anticipated improvements in patient welfare, according to a new study.

The law passed in the state of Massachusetts in 2014 required a 1:1 or 2:1 patient to nurse ratio in intensive care, with hopes that it would boost patient safety and outcomes.

“We did not identify improvements in patient outcomes associated with the state’s nursing requirements”

Anica Law

However, research published in the journal Critical Care Medicine has found the staffing regulations appeared to make little or no difference.

Under the state law, ICUs were required to implement 1:1 or 2:1 ratios based on patient acuity and anticipated care needs.

The ratios – for adult patients admitted to ICU for a day or longer – would be determined with the help of a patient acuity tool and the professional judgement of nurses on the unit in question.

The state’s six “academic ICUs” – in teaching hospitals – were required to comply with the new regulations by the end of March 2016, while all other hospitals had until the end of January 2017.

Researchers from the Beth Israel Deaconess Medical Centre – which is affiliated to Harvard Medical School – compared outcomes for patients in Massachusetts ICUs with 114 similar ICUs nationwide before, during and after the regulations came into force.

“The modest changes in nurse staffing we saw in Massachusetts remained unassociated with changes in hospital mortality” 

Anica Law

Lead author Dr Anica Law said they had expected to see improvements in patient outcomes as a result of the staffing regulations, but this was not the case.

“We hypothesized that Massachusetts ICU nurse staffing regulations would result in decreased complications and mortality for critically ill patients when compared with patients admitted to ICUs across the country unaffected by Massachusetts regulations,” she said.

“But we did not identify improvements in patient outcomes associated with the state’s nursing requirements,” noted Dr Law.

The analysis focused on mortality rates at academic ICUs but the team also looked at changes in community hospitals and outcomes for critically ill patients who needed support from a ventilator.

In addition, they looked at a range of complications including catheter-associated urinary tract infections, central line-associated bloodstream infections, hospital-acquired pressure ulcers and falls in which patients were injured.

They found there had been small increases in ICU nurse staffing ratios in Massachusetts following the introduction of the regulations. On average, ratios went from 1.38 patients per nurse to 1.28 patients per nurse.

However, the changes were not significantly higher than in other states where the staffing law was not in force, suggesting the increases in Massachusetts could not be attributed to the legislation.

“Efforts to regulate patient-to-nurse ratios should carefully first consider the extent of the effects on nurse staffing levels”

Anita Law

The risk of mortality and complications in Massachusetts’ ICUs also remained stable after the law was brought in, with no real difference compared with hospitals in other areas.

“Our results suggest that the Massachusetts nursing regulations were not associated with changes in staffing or patient outcomes,” said Dr Law.

“The modest changes in nurse staffing we saw in Massachusetts – approximately one extra nurse per 20-bed ICU per 12-hour shift – remained unassociated with changes in hospital mortality,” she said.

The research team said there were “multiple factors” that could have contributed to the minimal staffing changes and lack of improvements observed in Massachusetts.

These included the fact that staffing levels were adequate before the law was passed or the fact hospitals had “significant leeway” in choosing which acuity tool to use and how it was deployed.

The study’s limitations include the fact the researchers could not separate the impact of mandated patient-to-nurse ratios with using measures of acuity to work out staffing levels.

Other methods for deciding safe staffing levels may have had different results, they suggested.

“It is possible that our findings are the result of suboptimal nursing resource allocation as a result of the acuity tool alone, and that using other methods of nurse staffing distribution may yield different outcomes,” said the researchers.


Anica Law

Source: Beth Israel Deaconess Medical Center

Anica Law

The study did not look at the impact of the regulations on other important measures such as patient and family satisfaction and emotional wellbeing or on the nurses themselves when it came to job satisfaction and their working environment – all of which merits “further investigation”, they said.

Meanwhile, they noted that a longer study period might show legislation had prevented a decrease in nurse staffing levels or helped ensure staffing increased in line with rising patient complexity.

In the meantime, the study team concluded there were clear questions about whether it was cost-effective.

“Given the excess costs of enacting and enforcing statewide legislation to implement acuity-guided ICU nurse staffing, future efforts to regulate patient-to-nurse ratios should carefully first consider the extent of the effects of the mandate on nurse staffing levels,” they said in their study paper.

“In line with previous studies outside of the ICU, our study of ICU nurse staffing adds further evidence suggesting that statewide legislation to mandate nurse staffing strategies may not effectively improve patient outcomes,” they said.


Readers' comments (3)

  • Interesting research and an important antidote to the widespread calls for legislation as the answer to all our woes. However, the report here highlights something that is often overlooked when calling for mandatory ratios - there are two components - one is the legislation and the other is the ratio itself. If the mandated ratio doesn't change staffing levels much (as was the case here) it's unlikely to have much effect on outcomes, although there may be benefits from reducing extreme variation. The impact of this will depend on how often those extremes happen. As extremely low staffing in ICU is likely to be quite rare, any effect could be hard to detect. If we map to the UK, mandating staffing levels is not likely to have much effect unless it also substantially increased staffing levels in a lot of places. I think when people call for legislation that is what they are really asking for. It's important to be explicit or else you can get your legislation but no increase in staffing...

    Unsuitable or offensive? Report this comment

  • I think to compare nursing in the UK and the US is like comparing apples and oranges. I have not practiced in the US but as I live in Canada, I know many who have/ do and hear their stories.

    The US model is very different to that in the UK and Canada in the sense of who is providing a lot of the routine daily care. So I'm not sure that this story is relatable to the UK model. In addition it focuses on ICU nursing which, while often also being understaffed, generally still has 1:1 or 1:2 ratios. The problems I hear from my colleagues in the UK in that ward staff are chronically short staffed with terribly unsafe ratios, and experience a bigger problem providing safe, compassionate care.

    I fear that this study will be used as a distraction technique to suggest that those who call for extra staff and lower nurse:patient ratios are scaremongering and that employing more nurses won't help.

    Unsuitable or offensive? Report this comment

  • Ratios are also about preventing staff burnout. Nurses are people too.

    Unsuitable or offensive? Report this comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Links may be included in your comments but HTML is not permitted.