JMIR Publications

ABSTRACT

Background:

Type 2 diabetes mellitus (T2DM) has become a major health burden worldwide, therefore strategies to manage it in early stages are continuously being investigated. Excessive calorie consumption and sedentary lifestyles which are accompanied by the development of a low-grade inflammatory state, are one of the key risk factors for the development of prediabetes, metabolic syndrome and the subsequent T2DM. Lifestyle modifications like intermittent fasting (IF) have become an important aspect in the management of T2DM. Current evidence on the effects of IF on low-grade inflammation in individuals with either prediabetes, metabolic syndrome or T2DM is inconsistent. This systematic review protocol outlines the planned synthesis and evaluation of existing literature investigating the effectiveness of IF on inflammatory markers of adult patients with prediabetes T2DM or metabolic syndrome.

Objective:

The main objective of this review is to analyse data of previously published studies investigating effects of different IF regimens by assessing inflammatory markers of patients with prediabetes, metabolic syndrome or T2DM.

Methods:

This protocol is prepared in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis Protocol (PRISMA-P) 2020. Databases including PubMed/Medline, PubMed Central, Scopus and Google Scholar will be systematically searched for published randomized controlled trials and longitudinal studies, including cohort, case-control, cross-sectional, observational, retrospective and prospective studies involving all types of intermittent fasting in adult humans with prediabetes or T2DM OR metabolic syndrome. Eligible participants will be adults (≥18 years) diagnosed with metabolic syndrome, prediabetes or T2DM using the American Diabetes Association (ADA) or the World Health Organisation (WHO) criteria. Systematic reviews, conference abstracts, editorials and meta-analyses will be excluded. Additionally, studies without a control group will be excluded unless they provide baseline vs. follow-up inflammatory data. The control group in randomized controlled trials will consist of subjects on their usual diet, continuous energy restriction or standard diabetic care. Active comparators like Mediterranean diet will be allowed if inflammatory markers are reported. Data on changes in inflammatory markers between the intervention and control group, as well as between baseline and post intervention will be extracted. The extracted data will be verified by a second reviewer and disagreements will be resolved by a third reviewer. The risk of bias of the included randomized controlled trials will be assessed using the Cochrane Risk of Bias 2 (RoB 2), while for longitudinal studies the National Institutes of Health (NIH) quality assessment tool for Before-After (Pre-post) studies with no control group will be used. Review Manager (RevMan) will be used to perform a meta-analysis where sufficient data are available and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used to assess the quality of evidence.

Results:

This review will only use publicly available published data. The findings of this review will provide a comprehensive synthesis of the current evidence regarding the effects of intermittent fasting regimens on inflammatory markers of adult patients with either T2DM, prediabetes or metabolic syndrome.

Conclusions:

The findings will highlight the current knowledge gaps and inform future clinical research, which may help to guide early intervention strategies to manage prediabetes or metabolic syndrome and to prevent the onset of T2DM. Clinical Trial: International Prospective Register of Systematic Reviews (PROSPERO) CRD420251133867, https://www.crd.york.ac.uk/PROSPERO/view/CRD420251133867