During the early phase of the coronavirus disease 2019 (COVID-19) pandemic, a hypothesis was postulated that COVID-19 might induce new-onset diabetes. Since then, studies showing that the prevalence, incidence, and risk of new-onset diabetes in COVID-19 patients have been published.[1,2] However, little is known about the factors associated with developing new-onset diabetes in COVID-19 patients. To this end, the study by Keerthi et al., published in the Journal of Family Medicine and Primary Care, provides some insights into this issue. This prospective cohort study was conducted among 100 COVID-19 patients admitted to a tertiary care center in India from March 2021 to August 2021. Over 3 months of follow-up, 15 (15%) patients developed new-onset diabetes (glycated hemoglobin >6.4%). Patients who developed new-onset diabetes were significantly more likely to have a higher body mass index, family history of diabetes, moderate-to-severe illness on admission, and take steroids longer than those who did not develop diabetes (all P < 0.05). While these are conventional risk factors for the development of diabetes, weight loss showing a significant association is intriguing.
Research shows that weight loss in COVID-19 patients is primarily due to muscle loss (or sarcopenia). Several potential mechanisms may explain muscle loss when infected with severe acute respiratory syndrome virus 2, the virus that causes COVID-19, including direct invasion of the virus into the skeletal muscle through angiotensin-converting enzyme 2 receptors, severe inflammation due to the cytokine storm triggered by the virus, hypoxia, low appetite, reduced food intake due to vomiting and diarrhea, and decreased physical activity due to the acute nature of illness and fatigue.
The skeletal muscle is the largest organ system in the body. It is responsible for over 80% of postprandial glucose disposition and is a crucial insulin target organ for glucose uptake and utilization. Insulin resistance is caused when the skeletal muscle becomes less or insensitive to the insulin released from the pancreas to elicit glucose uptake, resulting in elevated blood glucose levels. As such, several studies have shown a positive association between muscle loss and diabetes incidence.
Future research should delineate weight loss into fat and muscle loss and assess whether muscle loss is directly related to developing new-onset diabetes in COVID-19 patients. Understanding this relationship would help inform the treatment strategies for the postacute sequelae of COVID-19, focusing on screening COVID-19 patients for muscle loss and providing nutritional support and rehabilitative exercise for patients with muscle loss.
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2. Zhang T, Mei Q, Zhang Z, Walline JH, Liu Y, Zhu H, et al Risk for newly diagnosed diabetes after COVID-19: A systematic review and meta-analysis BMC Med. 2022;20:444.
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