The relationship between nursing home staffing and resident safety outcomes: A systematic review of reviews

Background: Resident safety is an important topic for nursing home practice with up to 33 % of residents subjected to an adverse event. In spite of a large evidence base examining the relationship between nursing home staffing and resident outcomes, the findings of several systematic reviews remain inconclusive and contradicting, possibly due to methodological shortcomings.Objective: The main aim of this review was to provide a comprehensive overview of the literature on nursing home staffing and its relationship with resident safety outcomes.Design: We undertook a systematic review of reviews. We searched Medline, CINAHL and Embase by the end of November 2022. Reviews were included if they assessed the relationship between nursing home staffing and resident safety outcomes using objective measures and data at resident level. Quality appraisal was conducted using the SIGN-checklist, but we did not exclude any reviews based on quality assessment. We used a narrative approach, tables and figures to summarize the findings.Results: We included 13 systematic reviews published between 2006 and 2022 building on primary evidence from 1977 to 2022. Twelve reviews investigated the relationship between nurse staffing and resident safety outcomes (187 unique primary studies), and one review focused on allied health professionals (28 primary studies). Five reviews originated as work to inform governmental recommendations on staffing. We found diverse approaches used to investigate the staffing-outcome relationship with regard to design, timeframe, operationalization, data-source and theoretical rationales guiding the studies. The most prominently reported resident safety outcomes were pressure ulcers and urinary tract infections. Commonly reported staffing measures included number and level of education of nursing home staff. Based on narrative summaries, staffing seems to have a favorable relationship with resident safety outcomes, but logic models explaining the mechanisms of this relationship were sparsely reported. Conclusions: The existing literature shows methodological limitations that demand a change in research on the staffing-outcome relationship in the nursing home setting. Our work highlights the need for carefully designed primary studies that address the pertinent shortcomings by design, timeframe, operationalization, data-source and theoretical rationales. These future studies will allow to carefully examine the causal relationship between selected staffing measures and resident safety outcomes in further detail and serve as legitimate evidence bases to inform action plans for clinical practice and to evaluate staffing policies. Tweetable abstract: None.(c) 2023 The Author(s). Published by Elsevier Ltd.This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).