Accepted for/Published in: JMIR Research Protocols
Date Submitted: Jan 10, 2026
Date Accepted: Mar 25, 2026
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Assessment of Cardiorespiratory Fitness In Individuals With Type 2 Diabetes Mellitus: Systematic Review And Meta-Analysis Protocol
ABSTRACT
Background:
Reduced cardiorespiratory fitness (CRF) is a well-recognized but under-integrated complication of type 2 diabetes mellitus(T2DM), contributing substantially to cardiovascular morbidity, mortality, and reduced quality of life. Evidence related to pulmonary function, functional exercise capacity, and autonomic dysfunction inT2DM remains fragmented and methodologically heterogeneous. Globally, Diabetes mellitus poses a substantial threat to public well-being, significantly impacting illness rates and death tolls, thus presenting a formidable challenge for healthcare systems worldwide. Estimates from 2017 indicated over 425 million individuals were affected worldwide.
Objective:
This protocol describes a systematic review and meta-analysis that aims to synthesize evidence on cardiorespiratory fitness in adults with T2DM,evaluate associated clinical and demographic determinants, and examine relationships with glycemic control and diabetes-related outcomes.
Methods:
The protocol is registered with PROSPERO (CRD420251009300) and follows PRISMA-P guidelines. A comprehensive search of PubMed, Cochrane Library, Web of Science, ClinicalTrials.gov, WHO ICTRP, and grey literature will be conducted for studies published between 2013 and 2024. Randomized controlled trials, cohort studies, and cross-sectional and Case-control studies involving adults with T2DM will be included. Primary outcomes include pulmonary function test parameters, six-minute walk test distance, and heart rate variability indices. Two reviewers will independently screen studies, extract data, and assess risk of bias using RoB 2.0, Newcastle–Ottawa Scale, and the JBI critical appraisal tools, as appropriate. Meta-analyses will be performed using random-effects models when sufficient homogeneity exists. The GRADE framework will be used to assess the certainty of evidence.
Results:
This review will provide pooled estimates of cardiorespiratory fitness impairments in individuals with T2DM and identify key determinants influencing these outcomes.
Conclusions:
The findings will support evidence-based clinical assessment and guide future research on integrative cardiopulmonary and autonomic evaluation in T2DM. Clinical Trial: The protocol is registered with PROSPERO. Registration no.CRD420251009300
Citation
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