One of the most vulnerable indigenous populations to SARS-CoV-2 in Brazil, the Xavantes are experiencing an epidemic of another silent disease, considered a risk factor for the worsening of COVID-19: diabetes.
Researchers from Unifesp and USP found through retinal examinations a high prevalence of type 2 diabetes and an ophthalmic dysfunction caused by the disease (diabetic retinopathy). (Photo: Disclosure / Agência Fapesp)
A group of researchers from the Paulista School of Medicine of the Federal University of São Paulo (EPM-Unifesp) and the Ribeirão Preto School of Medicine of the University of São Paulo (FMRP-USP) found, through retinal examinations of 157 Indians from ethnicity, carried out before the new coronavirus pandemic, a high prevalence of type 2 diabetes and an ophthalmic dysfunction caused by the disease.
The results of the study, supported by FAPESP, were published in the journal Diabetes Research and Clinical Practice, of the International Diabetes Federation.
“Among the 157 Xavante Indians we examined, 95 [60,5%] had a diagnosis of diabetes “, says Fernando Korn Malerbi, postdoctoral fellow at the Department of Ophthalmology at EPM-Unifesp and first author of the study.
According to the researcher, diabetes can trigger eye problems such as diabetic retinopathy – damage to blood vessels in the retina caused by excess glucose in the blood. If this eye change is not detected and treated properly it can lead to blindness.
In order to diagnose cases of diabetic retinopathy and other possible ophthalmic disorders in indigenous populations, the researchers carried out retinography exams in Xavante Indians from the Volta Grande and São Marcos reserves, located in Mato Grosso. For this, they used a portable retinograph developed by the company Phelcom Technologies through a project supported by the Innovative Research in Small Business Program (PIPE).
Called Eyer, the portable retinograph is composed of a device that, coupled with a smartphone, makes accurate images of the retina, allowing the detection of diseases of the fundus of the eye at a much lower cost than conventional methods. In addition, it has the advantage of enabling the diagnosis by telemedicine, miles away from an ophthalmologist.
When the images are produced, the application that operates the device for lighting and retinal imaging sends them over the internet to a web system – called Eyer Cloud – that allows to store and manage patients’ exams.
If there is no access to wi-fi or 3G or 4G network at the time of the exam, the images are saved on the device and are sent to the cloud as soon as there is an internet connection.
In the case of examinations with the Xavante Indians, as Malerbi conducted the procedures, the diagnosis was made instantly, in the presence of the patients.
“When the lesions on the retina observed through the portable retinograph indicated a risk of blindness, we guided the patient, through interpreters, and sent them to the indigenous health care teams for follow-up and treatment,” says Malerbi.
Of the 95 patients diagnosed with diabetes, it was not possible to assess whether 23 of them (24.2%) had diabetic retinopathy due to the opacity of transparent eye tissues, such as the lens, caused by cataracts.
In the 72 Indians whose images obtained from the retina allowed the diagnosis of diabetic retinopathy, the researchers found that 16 had the disease and seven of them were at risk of blindness.
“We proved that the portable retinograph is a viable method for screening diabetic retinopathy, as it is a low-cost technology that can be used in remote communities, such as indigenous reserves, where the population is usually dispersed across several villages,” says Malerbi .
A previous study had already reported a 19.3% prevalence of diabetic retinopathy in Xavante Indians from the same reserves now visited by the researchers.
The increase in the prevalence of cases of this ophthalmological dysfunction in this indigenous population, now, may be due to the greater sensitivity of the fundus images obtained through the portable retinograph in comparison with the methodology used in the previous study, by indirect ophthalmoscopy.
Another hypothesis is that the health status of this indigenous population, which is one of the largest in the country, with approximately 17,000 Indians, distributed across nine reserves, has worsened over the past few years, assess the study’s authors.
A previous study of 932 ethnic Indians indicated that 66.1% had metabolic syndrome, defined as a condition in which risk factors for cardiovascular disease and diabetes mellitus occur at the same time.
Changes in their health profile and diet in the last decades, characterized by the consumption of industrialized foods and a sedentary lifestyle, led to this situation, the researchers evaluated.
“This indigenous group that traditionally was a hunter-gatherer has become more sedentary and has modified its traditional diet in recent decades, incorporating new foods with a high sugar content,” explains Malerbi.
In addition to the Xavantes, the researchers also performed retinal examinations on 33 Bororo Indians – another ethnic group threatened both by COVID-19 and by the fires that affect the Pantanal.
The results of the tests revealed that seven Bororo Indians had diabetes, of which one was diagnosed with severe diabetic retinopathy and was referred for treatment.
The article The feasibility of smartphone based retinal photography for diabetic retinopathy screening among Brazilian Xavante Indians (DOI: 10.1016 / j.diabres.2020.108380), by Fernando Korn Malerbi, Amaury Lelis Dal Fabbro, João Paulo Botelho Vieira Filho and Laercio Joel Franco, can be read by subscribers to the journal Diabetes Research and Clinical Practice at www.sciencedirect.com / science / article / abs / pii / S0168822720306331.