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Published on: January 7, 2018
Increased Insulin Resistance and Hyperglycaemia in Long COVID: A Systematic Review and Meta-Analysis
Abbas F Almulla1,2, Yingqian Zhang3,4, Chavit Tunvirachaisakul5
1Sichuan Provincial Center for Mental Health, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China.
Background:
Accumulating evidence suggests that long COVID (LC) is mediated by chronic immune activation, oxidative stress and metabolic dysregulation. These processes may impair glucose homeostasis and promote insulin resistance (IR). However, no prior meta-analysis has systematically and quantitatively evaluated IR indices and related biomarkers in LC compared with normal controls.
Objectives:
To systematically review and meta-analyse IR indices including HOMA-IR, HOMA-%B, HOMA-%S, insulin, fasting and random blood sugar (FBG, RBS), glycated haemoglobin (HbA1c), C-peptide and adipokine levels in individuals with LC compared with normal controls.
Methods:
PubMed, SCOPUS, SciFinder and Google Scholar databases were searched for relevant studies from inception to September 2025. Fifty-six eligible studies were included, comprising 9623 participants, 5340 LC patients and 4283 normal controls.
Results:
LC disease is characterized by elevated HOMA-IR (standardized mean difference, SMD = 0.539; 95% confidence interval, CI: 0.311; 0.766), insulin (SMD = 0.424; 95% CI: 0.113; 0.735), FBG and RBS (SMD = 0.734; 95% CI: 0.190; 1.277, SMD = 0.325; 95% CI: 0.133; 0.517). Furthermore, reduced HOMA-%S was observed in LC patients versus normal controls. Publication bias was generally low, though evidence of small-study effects was observed for several outcomes. The Immunological Confounder Scale was employed to evaluate study quality, revealing an overall intermediate methodological quality.
Conclusions:
Our results show that LC is associated with multiple abnormalities in glucose homeostasis, including increased HOMA-IR, hyperglycaemia and impaired insulin sensitivity indices, sustained metabolic disturbances beyond the acute phase.
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