Background: Malnutrition is a clinical problem with a high prevalence in hospitalized adult patients. Many nutritional screening tools have been developed but there is no consensus on which 1 is more useful. The purpose of this review protocol is to provide an overview of which nutritional screening tool is most valid to identify malnutritional risk in hospitalized adult patients and to analyze the sensitivity and specificity of the different tools. Methods: The protocol of this systematic review and meta-analysis was registered on the INPLASY website ( https://inplasy.com/inplasy-2020-9-0028/ ) and INPLASY registration number is INPLASY202090028. We will perform a systematic literature search of main databases: PubMed, EMBASE, CINAHL and Web of Science and the Cochrane database. Also, grey literature will be search. Peer-reviewed studies published in English, Portuguese or Spanish language will be selected. Screening of titles, abstract and full text will be assessed for eligibility by 2 independent blinded reviewers and any discrepancies will be resolved via consensus. After screening the studies, a meta-analysis will be conducted, if it is possible. Results: Results from this systematic review will help health professionals to identify malnutrition in hospitalized patients and to make decisions to prevent or treat it as well as provide new clues to researchers. Conclusion: Our systematic review will provide aknowledge about the most valid malnutrition risk screening tool in hospitalized adult patients.

Review question / Objective: The questions of interest for this systematic review are: 1. Which nutritional screening tool is most valid to identify malnutritional risk in hospitalized adult patients? 2. What are the INPLASY 1