Association between undernutrition and mortality and amputation outcomes in chronic limb threatening ischaemia: A systematic review

Objective:
Nutritional status plays a complex role in the pathophysiology and outcomes of chronic limb threatening ischaemia (CLTI). Undernutrition may be a modifiable risk factor. Given the variability in nutritional status concepts in CLTI outcomes studies, a systematic review examining the association between undernutrition and outcomes in patients with CLTI was conducted. 

Data Sources:
A systematic literature search of nine databases (Allied and Complementary Medicine Database [AMED], CINAHL Complete, Cochrane Library, Google Scholar, Ovid Medline, Ovid Embase, PubMed, Scopus, and Web of Science Core Collection databases) was conducted up to 23 May 2023. 

Review Methods:
Inclusion criteria were randomised controlled trials, cohort studies, and case control studies of patients with CLTI conducted after 1982 that reported the effect size for a nutritional status measure and the outcomes of death, amputation, or a composite of the two. Two reviewers independently performed screening, data extraction, and quality assessment, with a third independent reviewer resolving conflicts.

Results:
A total of 6 818 citations were screened, with 49 observational studies (31 from Japan) included in the review. The mean patient age ranged from 56.0 – 86.9 years. Most included patients were undergoing revascularisation. Unidimensional indicators of undernutrition (including low serum albumin, low body mass index, and zinc deficiency) as well as multidimensional measures (such as nutritional screening tool scores indicating undernutrition) were found to be associated with a statistically significant increased risk of death, amputation, and composite events in most studies. Effect sizes of the association were generally larger when multidimensional nutritional screening tools were used. However, the quality of evidence was poor, and certainty of evidence very low.

Conclusion:
Undernutrition is consistently associated with an increased risk of death and amputation in patients with CLTI, regardless of the measure used. Broader efforts to understand the framework of nutritional status and validation of nutritional screening tools in CLTI populations are needed.