Too few ward nurses linked to longer hospital stays and risk of death

Employing too few permanent nurses on hospital wards is linked to longer inpatient stays, readmissions, patient deaths, and ultimately costs more in lives and money, according to a long-term study led by the University of Southampton.

Researchers say understaffing of ward nurses risks harming hospital patients, and is a key contributor to nursing recruitment and retention issues.

The study also suggests that redressing this imbalance is cost-effective, saving around £5000 for each year of healthy life gained per patient. However it shows this isn’t the case if temporary agency staff are used to tackle shortfalls.

Findings are published in the journal BMJ Quality & Safety and the research was funded by the National Institute for Health and Care Research (NIHR).

To find out if investing in higher nurse staffing levels, to offset understaffing, is cost effective, the team set out to estimate the associations between registered nurse and healthcare assistant staffing levels, and the risk of patient deaths, readmissions and length of stay in acute adult inpatient wards.

They drew on data provided by four NHS hospital trusts in England with diverse nurse staffing levels, sizes and teaching status. Three of the trusts provided acute inpatient services predominantly from single hospital sites, and the fourth provided inpatient services across four sites within one city.

The researchers examined data from electronic healthcare records and staffing rosters, spanning the period April 2015 to March 2020 for a total of 626,313 patients in 185 different acute care wards.

Two main nursing team roles were included in the study: registered nurses, who have degree level training and are registered with the profession’s regulator; and nursing support staff (such as healthcare assistants), who don’t have this level of training and who are largely unregulated.

Findings showed that patients on wards understaffed by registered nurses (RNs) were more likely to die (5 percent vs 4 percent for those with adequate RN staffing levels), to be readmitted (15 percent vs 14 percent), and to stay in hospital longer (8 days vs 5 days). Similar figures showed for inadequate numbers of nursing support staff.

Patients who experienced understaffing received an average care shortfall of one hour 9 minutes in the first five days, while those who did not experience understaffing, received an average of three hours 22 minutes of care above the ward average.

During the study period, 31,885 patients died. Each day a patient experienced registered nurse understaffing during the first five days of their stay, the hazard of death and readmission increased by 8 percent and 1 percent, respectively. When all five days after admission were understaffed, length of stay increased by 69 percent.

Days of nursing support understaffing were also associated with similar increases in the hazard of death and length of stay, but the hazard of readmission fell very slightly.

The researchers calculated that eliminating understaffing of both nursing roles would cost an additional £197 per patient admission, avoiding 6,527 deaths during the study period and gaining 44,483 years of life in good health.

Overall, increasing staffing levels, and thus reducing length of stay, amounts to savings of £4728 per additional year of healthy life gained. However, if agency staff were used to address shortfalls, they were less effective and more costly.

Lead investigator Professor Peter Griffiths from the University of Southampton comments: “Our study gives no indication that it makes rational economic sense to target efforts to rectify low staffing only on the most acute patients. Not only is this logistically difficult, it also gives much less benefit at a considerably higher cost per unit improvement in outcome.

Study author Dr Christina Saville , also from Southampton, adds: “When considering alternative policy strategies, this study indicates the importance of prioritising investment in registered nurses employed on wards over support staff, as well as showing there are no shortcuts to employing enough RNs, as using temporary staff is more costly and less effective.”