Relationship between nurse staffing level and adult nursing-sensitive outcomes in tertiary hospitals of Korea: Retrospective observational study

Int J Nurs Stud. 2018 Apr;80:155-164. doi: 10.1016/j.ijnurstu.2018.01.001. Epub 2018 Jan 2.


Background: Nurse staffing level is an important factor on nursing sensitive outcome. The relationships of nurse staffing level with nursing sensitive outcomes such as mortality, upper gastrointestinal bleeding and pressure ulcer have been explored in the United States, Canada, Australia, and New Zealand. Lower level of hospital nurse staffing seems associated with more adverse outcomes, especially mortality. However, there is insufficient evidence of the nurse staffing level-outcome relationship in other indicators.

Objectives: This study was conducted to describe the status and prove the relationships of nurse staffing level with nursing sensitive outcome indicators for adult medical and surgical inpatients in Korea. Patient and hospital characteristics as covariates on nurse sensitive outcome were also explored.

Design: This was a retrospective observational study.

Setting: The study setting was all 46 tertiary hospitals in Korea.

Participants: We selected all anonymized patients aged 19 years or older and admitted at tertiary hospitals for two years (2013-2014) using electronic reimbursement claims data.

Method: Multiple logistic regression was used to examine relationships of nurse staffing level (accounted for full-time registered nurses in general ward only) with Nursing-sensitive outcomes (NSOs) adjusted for patient and hospital characteristics. NSOs included urinary tract infection, upper gastrointestinal tract bleeding, deep vein thrombosis, hospital-acquired pneumonia, pressure ulcer, sepsis, shock/cardiac arrest, CNS complication, in-hospital death, wound infection, physiologic/metabolic derangement and pulmonary failure.

Results: The total number of patients in 46 tertiary hospitals in Korea for two years was 3,665,307. Among these, number of patients who had at least one nursing-sensitive outcome was 338,369 (9.23%). The significant relationships of nurse staffing level with six nursing-sensitive outcome rates (urinary tract infection, upper gastrointestinal tract bleeding, hospital-acquired pneumonia, shock/cardiac arrest, in-hospital death, and wound infection) were shown. These six nursing-sensitive outcomes showed an increasing trend as nurse staffing level degraded even after adjusting for patient and hospital characteristics. When the nursing-sensitive outcomes between those of group 1 (bed-to-nurse ratio < 2:1) and group 3 (between 2.5:1 and 3:1) were compared, the adjusted incidence rate of shock/cardiac arrest showed the highest difference (1.06%).

Conclusion: We demonstrated strong evidence for the relationships of nurse staffing level with six nursing-sensitive outcomes. We can use this study to improve nursing quality and to inform patients of the nursing quality of hospitals so they can choose hospitals with better nursing quality. The nurse staffing level should be optimized for better outcomes.

Keywords: Health care; Indicators; Nursing care; Patient outcome assessment; Quality; Risk adjustment.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Humans
  • Inpatients
  • Nursing Staff, Hospital*
  • Outcome Assessment, Health Care
  • Personnel Staffing and Scheduling*
  • Republic of Korea
  • Retrospective Studies
  • Tertiary Care Centers / organization & administration*