ABSTRACT
BACKGROUND: Some months after the remission of acute COVID-19, some individuals show depressive symptoms, which are predicted by increased peak body temperature (PBT) and decreased blood oxygen saturation (SpO2). No data indicate whether Long COVID is associated with increased insulin resistance (IR) in association with neuroimmune and oxidative (NIO) processes. METHODS: This case control and retrospective cohort study used the homeostasis Model Assessment 2 (HOMA2) calculator© to compute ß-cell function, insulin sensitivity and resistance (HOMA2-IR) and measured the Beck Depression Inventory (BDI) and the Hamilton Depression Rating Scale (HAMD) in 86 Long COVID patients and 39 controls. RESULTS: Long COVID (3-4 months after the acute infection) is accompanied by increased HOMA2-IR, fasting blood glucose, and insulin levels; 33.7% of the patients versus 0% of the controls had HOMA2-IR values >1.8, suggesting IR. Increased IR was predicted by PBT during acute infection, and associated with depressive symptoms above and beyond the effects of NIO pathways (NLRP3 inflamasome, myeloperoxidase, protein oxidation). There were no significant associations between increased IR and the activated NIO pathways during Long COVID. CONCLUSION: Long COVID is associated with new-onset IR which may contribute to the onset of depressive symptoms due to Long COVID by enhancing overall neurotoxicity.