An umbrella review of meta-analyses/systematic reviews of COVID-19 outcomes in patients with and without diabetes from around the world found overall worse outcomes in patients with COVID-19 who had diabetes — with geographic differences.
Diabetes has been known to be a risk factor for poorer prognosis in COVID-19, but this is the first time a study has looked at the risks while factoring in the patients' location. In the study, diabetes almost doubled the rate of death from COVID-19, but good glucose control was a protective factor, and this seems to have differed across many of the countries studied, as well as within countries.
The review included 270,000 participants, with studies from North America, Europe, the Middle East, and the Far East. It was recently published in Endocrinology, Diabetes & Metabolism by Stavroula Kastora, MD, PhD, of the University of Aberdeen, UK, and colleagues.
In the pooled results, "people with diabetes were 1.87 times more likely to die with COVID, 1.59 times more likely to be admitted to ICU, 1.44 times more likely to require ventilation, and 2.88 times more likely to be classed as severe or critical, when compared to patients without diabetes." Anne L. Peters, MD, who was not involved in this research, summarized in an email to Medscape Medical News.
Patients treated in the United States or Europe fared best, and those in other areas, particularly China, Korea, and the Middle East, did the worst, said Peters, a professor of medicine at the University of Southern California (USC) Keck School of Medicine in Los Angeles. Older patients and those treated with insulin also had worse outcomes, and people with better glycemic control did better, she noted.
"These findings are interesting because they reveal that worse outcomes due to COVID-19 in people with diabetes can be reduced in the right setting," Peters said.
However, she also noted that while the findings revealed differences in outcomes between countries, "within a country there is variation in outcomes." For instance, within the United States and the United Kingdom, outcomes in the review differed based on whether people live in an area with higher or lower healthcare resources.
Kastora says the findings should serve as a wake-up call.
"We...show that good glycemic control may be a protective factor in view of COVID-19-related deaths," she noted in a press release from her university. "Ultimately, we have identified a disparity in COVID-19 outcomes between the eastern and western world," she added.
"In light of the ongoing pandemic, strengthening outpatient diabetes clinics, ensuring consistent follow up of patients with diabetes, and optimizing their glycemic control could significantly increase the chances of survival following a COVID-19 infection," she noted.
Francisco J. Pasquel, MD, MPH, who was not involved in the research, agreed. "This is an alert to the global community about the importance of prioritizing care and research resources focused on people with diabetes and COVID-19 to reduce the gaps in outcomes compared to those without diabetes," he said in an email to Medscape Medical News.
Pasquel is associate professor, endocrinology, at Emory University School of Medicine, Atlanta, Georgia.
Peters, too, concluded: "We must be vigilant in our efforts to improve diabetes control worldwide to help reduce the morbidity and mortality associated with diabetes and COVID-19 infection."
Pasquel speculated that multiple factors might explain the different COVID-19 outcomes in patients with versus without diabetes in different parts of the world.
These could include different hospital practices, hospital bed availability, ICU admission criteria, therapeutic alternatives, development and adoption of treatment guidelines, timing of the COVID-19 infection (early versus late in pandemic), and the virus variant.
Differences in "implementation of guidelines for glycemic control as well as the use/availability of different antihyperglycemic agents, both preadmission and during hospitalization could also potentially explain some discrepancies between countries," he added.
ICU Admission, Ventilator Need, and Mortality
The researchers performed an umbrella review of other reviews — based on 158 original articles (148 retrospective studies and 10 prospective studies, including 15 preprints) — that were published up to August 30, 2021.
Twenty-two studies were conducted in the EU (Denmark, France, Italy, Spain, Switzerland, and the United Kingdom), 90 were from the Far East (China and Korea), 16 were from the Middle East (Iran, Iraq, Israel, Kuwait, Oman, Qatar, and Turkey), and 30 were from North America (29 from the United States and one from Mexico).
Almost all studies were conducted in hospitalized patients except one, which was from a care home.
The total sample consisted of 270,212 patients, including 57,801 patients who were diagnosed with diabetes (488 with type 1 diabetes and 57,313 with type 2 diabetes).
Overall, 19% of the patients were admitted to ICU, 12% were placed on a ventilator, and 13.5% died during follow-up.
In the 59 studies that looked at ICU admission, this outcome was more likely among patients with versus without diabetes (odds ratio [OR], 1.59; P = .005), driven primarily by the increased risk of ICU admission in patients with diabetes in the 29 studies from the Far East (OR, 1.94; P < .0001).
There was no overall increased risk of ICU admission in patients with COVID and diabetes (versus no diabetes) in the eight studies from the Middle East (OR, 1.32; P = .26), the nine studies from the EU (OR, 1.20; P = .16), or the 13 studies from North America (OR, 1.57; P = .36).
In the 83 studies that looked at need for a ventilator, overall, there was a greater need in patients with versus without diabetes (OR, 1.44; P < .0001).
Among patients with COVID, those with diabetes had an overall increased need for a ventilator in the 10 studies from the Middle East (OR, 2.02; P = .01), the 51 studies from the Far East (OR, 1.61; P = .0001), and the eight studies from Europe (OR, 1.26; P < .0001), but not in the 14 studies from North America (OR, 0.71; P = .19).
Overall, in the 136 studies that looked at mortality, patients with diabetes and COVID-19 had an increased risk of dying during follow-up (OR, 1.75; P < .0001). This was also true overall for patients with diabetes in the 77 studies from the Far East (OR, 2.40), the 15 studies from the Middle East (OR, 1.71; P < .0001), the 18 studies from Europe (OR, 1.47; P = .04), and the 14 studies from North America (OR, 1.42; P = .04) that looked at this outcome.
The authors have reported no relevant financial relationships. Peters has reported receiving consulting fees from Abbott, Novo Nordisk, AstraZeneca, Zealand, Vertex, and Medscape, and research funding from Abbott, Dexcom, and Insulet, and having stock options with Omaha Health and Teladoc.
Endocrinol Diab Metab. Published online April 20, 2022. Article