High blood glucose at admission, insulin use raise risk for COVID-19 mortality in diabetes
People with diabetes who have elevated blood glucose levels at admission and those who take insulin are at increased risk for COVID-19 mortality, according to data from a systematic review and meta-analysis published in Diabetologia.
“Individuals with a more severe course of diabetes have a poorer prognosis of COVID-19 compared with individuals with a milder course of diabetes,” Sabrina Schlesinger, PhD, head of the junior research group for systematic reviews at the German Diabetes Center in Düsseldorf, Germany, told Healio. “These findings can be helpful for identifying people with diabetes and COVID-19 at high risk for poor outcomes and, therefore, those most likely to require early vaccination or early intensified treatment.”
Schlesinger and colleagues conducted a systematic review and meta-analysis of studies analyzing the risk for severe COVID-19 or related death in people with diabetes. Researchers searched PubMed, Web of Science, Epistemonikos and the COVID-19 Research Database for studies through Oct. 10, 2020. Summary relative risks were calculated, and two authors independently graded each pooled association’s certainty as very low, low, moderate or high.
There were 22 studies with a total of 17,687 participants with diabetes in the analysis. Fourteen of the 22 studies were conducted in Asia, five took place in North America and three in Europe. Most of the studies were conducted in the hospital setting, with one using data from a national registry and two using health insurance records.
There were several associations observed with a moderate or high certainty of evidence. Men with diabetes had an increased risk for COVID-19-related mortality (summary RR [SRR] = 1.28; 95% CI, 1.02-1.61) and severe COVID-19 (SRR = 1.36; 95% CI, 1.13-1.64) compared with women. People with diabetes aged 65 years and older had a higher risk for COVID-19 death compared with younger adults (SRR = 3.49; 95% CI, 1.82-6.69). With each 5-year increase in age, the risk for COVID-19-related mortality increased by 43% and the risk for severe COVID-19 increased by 25%.
Only a few studies investigated diabetes-specific factors linked to COVID-19, making most of the certainty of evidence low or very low. Of associations graded with moderate or high certainty, people with a blood glucose level higher than 11 mmol/L at first admission had an increased risk for COVID-19-related death (SRR = 8.6; 95% CI, 2.25-32.83). Those who were chronic insulin users also had a higher risk of COVID-19-related mortality compared with people who did not use insulin (SRR = 1.75; 95% CI, 1.01-3.03) and metformin users had a lower risk for COVID-19-related mortality compared with people who did not use metformin (SRR = 0.5; 95% CI, 0.28-0.9).
Participants with chronic obstructive pulmonary disease had an increased risk for COVID-19-related mortality (SRR = 1.4; 95% CI, 1.21-1.62) and severe COVID-19 (SRR = 1.36; 95% CI, 1.11-1.66). There were also moderately strong associations found for an increased risk for COVID-19-related mortality among people with cardiovascular disease (SRR = 1.56; 95% CI, 1.09-2.24) and chronic kidney disease (SRR = 1.93; 95% CI, 1.28-2.9).
“Hypertension and obesity were identified as risk factors for COVID-19 severity among the general population,” Schlesinger said. “Surprisingly, these risk factors were not identified for patients with diabetes in this meta-analysis. However, more studies on this topic are warranted.”
Schlesinger said the living systematic review and meta-analysis will continue to be updated as more relevant studies become available, adding that more studies focused explicitly on diabetes-specific factors and their associations with severe COVID-19 and COVID-19-related mortality are needed.
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Sabrina Schlesinger, PhD, can be reached at firstname.lastname@example.org.