title: The effects of a one-to-one nurse-to-patient ratio on the mortality rate in neonatal intensive care: a retrospective, longitudinal, population-based study.
abstract: OBJECTIVE
  To estimate the effect of the provision of a one-to-one nurse-to-patient ratio on mortality rates in neonatal intensive care units.
  
  
  METHODS
  A population-based analysis of operational clinical data using an instrumental variable method.
  
  
  METHODS
  National Health Service neonatal units in England contributing data to the National Neonatal Research Database at the Neonatal Data Analysis Unit and participating in the Neonatal Economic, Staffing, and Clinical Outcomes Project.
  
  
  METHODS
  43 tertiary-level neonatal units observed monthly over the period January 2008 to December 2012.
  
  
  METHODS
  Proportion of neonatal intensive care days or proportion of intensive care admissions for which one-to-one nursing was provided.
  
  
  RESULTS
  Monthly in-hospital intensive care mortality rate.
  
  
  RESULTS
  Over the study period, the provision of one-to-one nursing in tertiary neonatal units declined from a median of 9.1% of intensive care days in 2008 to 5.9% in 2012. A 10 percentage point decrease in the proportion of intensive care days on which one-to-one nursing was provided was associated with an increase in the in-hospital mortality rate of 0.6 (95% CI 1.2 to 0.0) deaths per 100 infants receiving neonatal intensive care per month compared with a median monthly mortality rate of 4.5 deaths per 100 infants per month. The results remained robust to sensitivity analyses that varied the estimation sample of units, the choice of instrumental variables, unit classification and the selection of control variables.
  
  
  CONCLUSIONS
  Our study suggests that decreases in the provision of one-to-one nursing in tertiary-level neonatal intensive care units increase the in-hospital mortality rate.
authors: Warwick Medical School, University of Warwick, Coventry, UK.
authors: S I
authors: http://orcid.org/0000-0002-4298-3549
authors: SI
authors: Watson
authors: Department of Economics, University of Warwick, Coventry, UK.
authors: W
authors: W
authors: Arulampalam
authors: Warwick Medical School, University of Warwick, Coventry, UK.
authors: S
authors: S
authors: Petrou
authors: Academic Neonatology, UCL Institute for Women's Health, London, UK.
authors: N
authors: N
authors: Marlow
authors: Academic Neonatology, UCL Institute for Women's Health, London, UK.
authors: A S
authors: http://orcid.org/0000-0003-4143-1977
authors: AS
authors: Morgan
authors: Department of Health Sciences, University of Leicester, Leicester, UK.
authors: E S
authors: ES
authors: Draper
authors: Section of Neonatal Medicine, Department of Medicine, Chelsea and Westminster Campus, Imperial College London, London, UK.
authors: N
authors: N
authors: Modi
mesh_terms: D004739:England / Q000453:epidemiology; D017052:Hospital Mortality; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D016014:Linear Models; D008137:Longitudinal Studies; D009741:Nursing Staff, Hospital / Q000600:supply & distribution*; D012189:Retrospective Studies; D013222:State Medicine; D000078329:Workforce
keywords: Mortality; Neonatal intensive care unit; Nurse to patient ratio; Nursing