Diabetic retinopathy tied to increased intubation risk in COVID-19
Individuals with diabetic retinopathy who were hospitalized with COVID-19 had an elevated risk of requiring intubation, according to a recent study.
“[W]e observed a more than fivefold increased risk of intubation in patients with diabetic retinopathy,” said study first author Dr Antonella Corcillo from the School of Cardiovascular Medicine and Sciences, Kings College London, UK, and co-authors.
“This is the first time that retinopathy has been linked to severe COVID-19 in people with diabetes,” she said.
This single-centre study involved 187 patients with diabetes (179 with type 2 diabetes; mean age 68 years, 60 percent male, 39 percent Caucasian) who were hospitalized at Guy’s and St Thomas’ NHS Foundation Trust, London, UK, with PCR-confirmed COVID-19 between March 12 and April 7, 2020. Mean HbA1c prior to hospital admission was 8.6 percent.
NHS Diabetic Eye Screening data was used to identify presence and grade of diabetic retinopathy within 12 months of hospitalization for COVID-19. Thirty-six percent of patients had diabetic retinopathy (n=67), with 20 percent having more advanced retinopathy (ie, pre-proliferative or proliferative retinopathy).
Twenty-six percent of patients (n=49) were intubated. Of these, 45 percent had diabetic retinopathy. [Diabetes Res Clin Pract 2020;doi:10.1016/j.diabres.2020.108529]
Univariate analysis showed that diabetic retinopathy and obesity (BMI ≥30 kg/m2) were associated with an increased risk of intubation (coefficient of correlation [r], 0.13; p=0.09 and 0.23; p=0.01, respectively). Conversely, age (r, 0.39; p<0.001), diabetes duration (r, 0.17; p=0.03), and presence of macrovascular complications (r, 0.25; p=0.001) or chronic kidney disease (CKD; r, 0.14; p=0.06) were negatively associated with intubation.
Multivariate analysis showed that individuals with diabetic retinopathy had an independent and significantly increased risk of intubation (odds ratio [OR], 5.81, 95 percent confidence interval [CI], 1.37–24.66; p<0.001).
In contrast, diabetes duration, macrovascular complications, CKD, and BMI 30 kg/m2 were not significantly tied to increased intubation risk.
Younger age was also associated with an increased risk of intubation (OR, 0.89, 95 percent CI, 0.84–0.95; p<0.001). However, this may be due to selection bias, with a lower likelihood of intubation in elderly or more frail patients, the authors noted.
Sixty deaths occurred. There was no association between presence of diabetic retinopathy and mortality. Seventeen of the intubated patients died, as did 43 of those who were not intubated.
“There is increasing evidence that there is significant damage to the blood vessels in the lung and other organs in patients hospitalized with severe COVID-19,” said senior author Dr Janaka Karalliedde, also from King’s College London. “People with diabetes are at high risk of vascular complications affecting the large and small blood vessels.”
“Retinopathy is a marker of damage to the blood vessels and our results suggest that such pre-existing damage to blood vessels may result in a more severe COVID-19 infection requiring intensive care treatment,” said Corcillo.
A lack of information on albuminuria or neuropathy pre-hospitalization precluded identification of association between these factors and intubation risk. The mechanisms behind the retinopathy–intubation link could also not be ascertained in this study.
“We hypothesize that the presence of diabetes-related vascular disease such as retinopathy may result in greater vulnerability and susceptibility to respiratory failure in severe COVID-19,” said Karalliedde.
“Endothelial damage and pulmonary microvascular thrombosis found in severe COVID-19 patients may … be enhanced in patients with diabetes who have surrogate evidence of microangiopathy such as retinopathy,” the authors said, though further research is required to conclusively establish the mechanism.
“[L]ooking for presence or history of retinopathy or other vascular complications of diabetes may help healthcare professionals identify patients at high risk of severe COVID-19,” suggested Karalliedde.