Consequences, costs and cost-effectiveness of workforce configurations in English acute hospitals

The National Health Service faces significant challenges in recruiting and retaining registered nurses. Recruiting unregistered staff is often adopted as a solution to the registered nurse shortage, but recent research found lower registered nurse staffing levels increase hospital mortality with no evidence that higher levels of assistant staff reduced risk.

To estimate the consequences, costs and cost-effectiveness of variation in the size and composition of the staff on acute hospital wards in England. To determine if results are likely to be sensitive to staff groups such as doctors and therapists, who are not on ward rosters, associations between staffing and outcomes for multiple staff groups, including medical, are explored at hospital level.

A national cross-sectional panel study and a patient-level longitudinal observational study using routine data.

All English acute hospital Trusts and a subsample of four Trusts for the patient-level study.

Naturally occurring variation in the size and composition of the workforce.

Patients experiencing a hospital admission with an overnight stay and nursing staff providing care on inpatient wards.

Death, patient and staff experience, length of stay, re-admission, adverse events, incidents (Datix), staff sickness, costs and quality-adjusted life-years.

Publicly available records of hospital activity, staffing and outcomes (cross-sectional study) and hospital administrative systems (longitudinal study).

In the cross-sectional study, lower staffing levels from doctors and allied health professionals were associated with increased risk of death. Higher nurse staffing levels were associated with better patient experience and staff well-being. In the longitudinal study, for adult inpatients, exposure to days with lower-than-expected registered nurses or nursing assistant staff was associated with increased hazard of death (adjusted hazard ratio 1.08/1.07, 95% confidence interval 1.07 to 1.09/1.06 to 1.08) and longer hospital stays. Low registered nurse staffing was also associated with increased hazard of re-admission (adjusted hazard ratio 1.01, 95% confidence interval 1.01 to 1.02). Eliminating low staffing cost £2778 per quality-adjusted life-years gained. Avoidance of registered nurse understaffing gave more benefits and was more cost-effective for highly acute patients. Although high bank or agency staffing was associated with increased hazard of death, avoiding low staffing using temporary staff still reduced mortality but was more costly and less effective than using permanent staff. If costs of avoided hospital stays are included, avoiding low staffing generates a net cost saving. Exploration of thresholds for low staffing indicated a greater beneficial effect from registered nurse staffing higher than current norms.

This is an observational study. Causal inferences cannot be made from these results in isolation. Quality-adjusted life-years gains were estimated, although conclusions are not sensitive to assumptions or discount rates. We used current ward norms as reference for low staffing.

Our results show the adverse effects of low nurse staffing but also show that medical and allied health professional staffing are important considerations for patient safety. Eliminating low registered nurse staffing gave more benefits than eliminating assistant staffing.

Research is needed to validate methods to determine nurse staffing requirements, and the interaction between registered nurse and assistant staffing needs further exploration.

This study is registered as Current Controlled Trials ClinicalTrials.gov NCT04374812.

This award was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (NIHR award ref: NIHR128056) and is published in full in Health and Social Care Delivery Research; Vol. 13, No. 25. See the NIHR Funding and Awards website for further award information.