The coronavirus disease 2019 (COVID-19) pandemic has claimed nearly 1.461 million lives across the world. Studies have shown that COVID-19 patients who have diabetes are at greater risk of hospitalization, ICU admission, and intubation, compared to patients without diabetes. Although diabetes is a common comorbidity in fatal COVID-19 cases, whether diabetes is directly associated with COVID-19 mortality is not clear.
Some previous studies have suggested an association between diabetes and mortality in COVID-19 patients, but many others have not been able to confirm this association. These discrepancies between studies may be due to the lack of enough subjects to assess mortality risk, analyzing only severe COVID-19 or critically ill patients, the use of composite outcomes, the age group of study participants and the inclusion of unconfirmed cases in the study.
Examining the risk of death associated with diabetes in symptomatic COVID-19 patients
The association of diabetes with COVID-19 mortality across various age groups has not been thoroughly studied, but it is necessary to clarify this association as it may have important clinical implications for risk stratification. Researchers from the Institute for Globally Distributed Open Research and Education (IGDORE), Los Angeles, California and Hospital Nacional Docente Madre Niño San Bartolomé, Lima, Peru, recently examined the mortality risk associated with diabetes in symptomatic COVID-19 patients. Their study has been published in the preprint server medRxiv*.
The researchers performed a retrospective case-series analysis where they examined the association between risk of death and self-reported diabetes in symptomatic adult patients with COVID-19 confirmed by a laboratory. The patients were identified through the System of Epidemiological Surveillance of Viral Respiratory Disease in Mexico between January 1 and November 4, 2020.
COVID-19 patients with diabetes had a 49% higher risk of death compared to those without diabetes
The study included about 757,210 COVID-19 patients, of which 120,476 (16%) patients had diabetes. 80,616 of the patients had died. Patients with diabetes were at a 49% higher risk of death compared to those without diabetes, after adjusting for sex, age, obesity, smoking habit, immunodeficiency, hypertension, cardiovascular, pulmonary, and chronic renal disease.
The relative mortality risk associated with diabetes decreased with age (P=0.004). The 28-day survival for in-patients with diabetes was 73.5%, and those without diabetes was 85.2% in patients belonging to the age group 20-39 years; 66.6% and 75.9%, respectively, for patients in the 40-49 years age group; 59.4% and 66.5%, respectively, for patients in the 50-59 years age group; 50.1% and 54.6%, respectively, for patients in the 60-69 years age range; 42.7% and 44.6% respectively, for patients in the 70-79 years age group; and 38.4% and 39.0%, respectively, for patients who were 80 years or older.
Association between diabetes and mortality in COVID-19 patients not stronger than that in patients without COVID-19
Based on the 28-day follow-up results, this large population study of symptomatic COVID-19 patients from Mexico shows that COVID-19 patients with diabetes have a higher mortality risk compared to those without diabetes. The relative mortality risk associated with diabetes decreased with age and was stronger in out-patients than it was in hospitalized patients. However, the actual incidence of death increased with age and was higher in hospitalized patients than that in out-patients.
“Our analysis of a large population of symptomatic adult patients with COVID-19 in Mexico (>750,000) shows that those with diabetes have increased risk of death during a follow-up of 28 days.”
Many previous studies have shown that diabetes is a common condition in hospitalized COVID-19 patients. In this study, the proportion of diabetic patients among hospitalized COVID-19 patients was as high as those without COVID-19. The proportion of diabetic patients was also similar in both groups (about 40%) among deceased patients. Although some past studies suggested an association between diabetes and COVID-19 mortality, many others could not find a significant association between the two.
Although this study showed an association between diabetes and mortality in COVID-19 patients, the association was not stronger than that seen in patients without COVID-19. The study findings also suggest that the association between diabetes and COVID-19-related mortality varies with age.
“Our study shows a detailed comparison of the association of diabetes with mortality across age groups in a Hispanic-Latino population in Mexico, a country that has one of the highest numbers of deaths in the world due to COVID-19.”
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.