Africa: Sight-Threatening DR on the Rise

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Althouth the International Diabetes Foundation estimates that the number of adults diagnosed with diabetes in Africa will increase from 12.1 million in 2010 to 23.9 million in 2030, there is a paucity of evidence on diabetic eye disease in that continent. Recently, however, the first prospective longitudinal study of diabetic retinop­athy (DR) from sub-Saharan Africa has been published by researchers with the Malawi Diabetic Retinopathy Study (MDRS) to characterize the incidence, progression, and factors associated with DR in patients at 2 diabetes clinics in southern Malawi.¹

Striking difference in DR progres­sion. According to lead author Philip I. Burgess, MRCS(Ed), PhD, a retina specialist with the Malawi-Liverpool-Wellcome Trust Clinical Research Programme, the most important find­ing is the high rate of progression to sight-threatening diabetic retinopathy seen in the MDRS patients—the rate is approximately 3 times that reported in recent European studies.

Multiple factors contribute to this disparity, Dr. Burgess said: “The agenda is dominated at a national level by poorly resourced health services and at a community level by poverty. A major challenge is lack of patient knowl­edge of the disease and the logistics of accessing care on a regular basis. Throughout sub-Saharan Africa, referral pathways between diabe­tes clinics and ophthalmic services are underdeveloped and poorly organized.”

Reasons for hope. Despite these troubling find­ings, Dr. Burgess noted that a number of DR detection and treatment programs have recently been developed in African countries. He cited the Kilimanjaro Diabetic Programme in northern Tanzania as an example of an integrated, clinic-based, mobile photographic retinal screening service. Another important development is the Commonwealth Diabetic Retinopathy Network, in which U.K. eye units part­ner with centers in low- and middle-income countries.

Although DR screening and care delivery models from industrialized countries are unlikely to be adopted in resource-poor settings, he said, “New technologies including portable fundus cameras and automated grading of retinal images will help deliver cost-effective services in African countries.”

The MDRS progression data can be an important aid in planning the introduction of programs for preven­tion, early detection, and management of DR in the region, said Dr. Burgess. “Our findings represent a baseline against which the efficacy and cost-effectiveness of such interventions can be judged.”

A surprising finding. The most un­expected finding in the study, said Dr. Burgess, was a negative association be­tween HIV infection and DR progres­sion. “HIV infection and antiretroviral agents are associated with macro- and microvascular pathology. We therefore expected those subjects with HIV and diabetes to demonstrate increased rates of DR progression.” A possible con­founder is that people with HIV receiv­ing antiretroviral drugs already have contact with health services, so their diabetes might have been diagnosed earlier. And, more ominously, “In our study, subjects with HIV and diabetes had a very high mortality rate (approx­imately 18% in 24 months), which may have reduced the observed rate of DR progression in this group,” he said.

Ways to help. Ophthalmologists and allied health professionals from high- and middle-income countries have an important role to play in the develop­ment of services for diabetes and DR in African countries, said Dr. Burgess, but it must be done in partnership with local clinicians, using a systematic approach to planning for sustainability and accessibility. “Long-term partner­ships between institutions are most likely to provide the most benefit for all parties. Provision of subspecialty train­ing to local ophthalmologists either in their country of origin or elsewhere is extremely important” and will facilitate the development “of local clinician-scientists who can provide health policy leadership in the region.”

—Peggy Denny

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1 Burgess PI et al. Ophthalmology. Published online July 9, 2016. doi:10.1016/j.ophtha.2016.05.042.

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Relevant financial disclosures—Dr. Burgess: None.

For full disclosures and disclosure key, see below.

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