From the Journals

Inflammatory markers may explain COVID-19, diabetes dynamic



COVID-19 infection in patients with type 2 diabetes is associated with a greater increase in inflammatory and coagulation markers, compared with COVID-19 patients without diabetes, according to preliminary findings from a retrospective analysis of COVID-19 patients in Wuhan, China.

The results, though preliminary, could help explain why patients with diabetes and COVID-19 are at greater risk for more severe disease and death.

The results also suggest that more severe disease in patients with diabetes may be the result of a cytokine storm, in which the patient’s immune system overreacts to the virus and inflicts collateral damage on its own organs, according to Herbert I. Rettinger, MD, a clinical endocrinologist in Orange County, Calif., and member of the editorial advisory board for Clinical Endocrinology News. “Understanding the mechanism might help us understand the best way to treat,” COVID-19 in patients with diabetes, he said in an interview.

Dr. Rettinger, who was not involved in the research, noted that the study included only 24 patients with diabetes. Nevertheless, the finding of heightened inflammatory and coagulation markers was “fascinating.”

“This is the first paper I’ve seen [suggesting] that. I don’t know if we can extrapolate [the findings] to other populations, but if biomarkers are elevated in patients with COVID-19 and diabetes, then it’s something worth looking into, and to be aware of and cautious of. We need to pay attention to this,” he commented.

The study was led by Weina Guo and Desheng Hu at Huazhong University of Science and Technology in Wuhan, China, and published in Diabetes/Metabolism Research and Reviews.

The sample included 174 patients with COVID-19, who were treated consecutively during Feb. 10-29, 2020, at a single center. The researchers first assigned the patients to one of two groups – those with comorbid diabetes and those without. They further excluded all other comorbidities, focusing only on 26 patients with no comorbidities and 24 with only diabetes as a comorbidity, to remove all other comorbidities as possible confounding factors. Patients in the diabetes group were significantly older than those without diabetes (61 vs. 41 years, P < .01). The mortality rate was 16.5% in patients with diabetes and 0% in those without (P = .03).

COVID-19 patients with diabetes alone as a comorbidity had a greater risk for severe pneumonia, as evidenced by a higher mean CT score, compared with those without diabetes and no other comorbidities (P = .04). Patients with diabetes also had higher measures of release of tissue injury–related enzymes and were at higher risk of uncontrolled inflammation and hypercoagulable state. In particular, they had higher levels of interleukin-6 (13.7 vs. 4.1 pg/mL, respectively; P < .01), C-reactive protein (76.4 vs. 7.43 mg/L; P < .01), serum ferritin (764.8 vs. 128.9 ng/mL; P < .01), and D-dimer (1.16 vs. 0.25 mcg/mL; P < .01).

“It’s noteworthy that, for diseases that can induce a cytokine storm, IL-6 is a very good predictor of disease severity and prognosis, and its expression time is longer than other cytokines ([tumor necrosis factor] and IL-1). In addition, a significant rise in serum ferritin indicates the activation of the monocyte-macrophage system, which is a crucial part of inflammatory storm. These results indicate that patients with diabetes are susceptible to form an inflammatory storm, which eventually lead to rapid deterioration of COVID-19,” the authors wrote.

They also cited previous findings suggesting that coronavirus might exacerbate, or even cause, diabetes by seriously damaging islets (Acta Diabetol. 2010;47[3]:193-9). “Since viral infection may cause sharp fluctuation of the blood glucose levels of diabetes patients, which adversely affect the recovery of patients, there is reason to suspect that diabetes combined with SARS-CoV-2 pneumonia may form a vicious circle,” they wrote.

That’s one more reason to carefully monitor diabetes patients, said Dr. Rettinger. “Those patients who are able to make insulin might not be able to do so with the infection, and that may last a while, and they may require insulin. You want to keep a watch on things, and if oral agents are not working well, you want to go to insulin as quickly as you can. Probably diabetics should be way more careful and maybe visit the emergency department at earlier than a nondiabetic would.”

Dr. Raghu Mirmira

Dr. Raghu Mirmira

Raghavendra Mirmira, MD, PhD, who conducts translational research on diabetes and insulin production, said that the finding was not a complete surprise to him. “With a lot of diseases, having diabetes as a comorbidity can mean worse outcomes, and that’s certainly true of influenza. It was true for the other COVID-like illnesses, such as SARS and MERS,” Dr. Mirmira, who was not involved in the research, said in an interview.

If the findings hold up in larger numbers of patients and across multiple centers, they have the potential to inform patient management, said Dr. Mirmira, director of the Translational Research Center in the department of medicine at the University of Chicago. That will be especially true as data from long-term follow-up of become available. Elevated values in some biomarkers might dictate a patient be sent straight to the ICU or dictate admission to the hospital rather than being sent home, or it could assist patient selection for some of the new therapies that physicians hope will become available.

“The more information we get [about] total outcome, the more informed we’d be about who would benefit from some of the therapies that are in clinical trials now,” he said. Still, it will be a challenge to prove causation, because patients with diabetes have unique clinical characteristics that could also be the source of the difference.

Dr. Mirmira noted that patients with diabetes only were 20 years older on average than those with no comorbidities. “It’s really hard to know if what you’re looking at for the worse outcomes for people with diabetes is because they were older, and we know that older people tend to do much worse with COVID than younger people.” Ideally, patients would also be matched by age, but there are not enough data to do that yet.

The study was funded by the China National Natural Science Foundation. The authors reported no conflicts of interest. Dr. Rettinger has no relevant financial disclosures. Dr. Mirmira is on scientific advisory boards for Veralox Therapeutics, Sigilon Therapeutics, the Indiana Biosciences Research Institute, and the Juvenile Diabetes Research Foundation.

SOURCE: Guo W et al. Diabetes Metab Res Rev. 2020 Mar 31. doi: 10.1002/dmrr.3319.

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