Examining the Relationship between Nurse Staffing Levels and Inpatient Mortality: A Longitudinal Shift-Level Analysis
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Abstract
Healthcare facilities globally are under pressure to reduce expenses, leading some to operate with fewer nurses or personnel with lower qualifications.
Objective: This study aims to investigate the correlation between inpatient mortality rates and shifts characterized by varying nurse staffing levels.
Methods: Utilizing longitudinal data , this study analyzed shift-, unit-, and patient-level data for 55 units, 79,893 adult inpatients, and 3646 nurses (comprising 2670 registered nurses, 438 licensed practical nurses, and 538 unlicensed and administrative staff). A staffing model was developed to categorize shifts as high or low staffed, followed by logistic regression analysis to examine the association between nurse staffing and mortality.
Results: Exposure to shifts with higher levels of registered nurses correlated with an 8.7% decrease in mortality odds [odds ratio 0.91, 95% CI 0.89–0.93]. Conversely, lower staffing levels were linked to a 10% increase in mortality odds [odds ratio 1.10, 95% CI 1.07–1.13]. The impact of staffing levels among other personnel categories was less evident. Specifically, both high and low staffing of unlicensed and administrative personnel were associated with higher mortality rates, with odds ratios of 1.03 [95% CI 1.01–1.04] and 1.04 [95% CI 1.03–1.06], respectively.
Discussion and Implications: This longitudinal study at the patient level indicates a significant relationship between registered nurses' staffing levels and mortality rates. Higher registered nurse levels were found to positively influence patient outcomes, while lower levels had a negative impact. The contributions of other personnel groups to patient safety were inconclusive based on these findings, suggesting caution against substituting these groups for registered nurses.
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