Diabetic Retinopathy Management Guidelines

Rahul Chakrabarti; C Alex Harper; Jill Elizabeth Keeffe

Disclosures

Expert Rev Ophthalmol. 2012;7(5):417-439. 

In This Article

Epidemiology of DR

The need to estimate the demand for DR services is a critical step in the development of clinical guidelines. Worldwide, the global burden of diabetes is estimated at 346 million people.[8] This is projected to increase to 438 million by the year 2030 (4.4% of the estimated world population). While this escalating trend of diabetes was acknowledged across all the guidelines, many were deficient in documenting county-specific population data that would be pertinent in planning and implementing services to manage DR.

The prevalence of diabetes and DR within respective countries and regions were documented to varying quality by the major guidelines (Table 2). In the guidelines published from Europe, North America, India, Malaysia and Australia, regional prevalence of diabetes was documented. Comparatively, the guidelines from low-resourced areas including Kenya, South Africa and Pacific Islands were deficient in basic population data on diabetes, let alone retinopathy. However, much of the quoted data were based on studies that were at least 5 years old, with limited projections of trends of diabetes in these regions. Guidelines from developed countries generally identified that the majority of diabetes was diagnosed in people aged older than 60 years. This was in contrast to Wild et al. who showed that the majority diagnosed with diabetes in developing nations are at a younger age group (45–64 years of age).[9] This will clearly have long-term implications for retinopathy progression (longer duration of disease), and impact on morbidity and loss of productivity associated with vision impairment.

The growth of diabetes and DR is a major concern for developing countries. However, this was not necessarily conveyed within the published guidelines. Since the time of publication of most guidelines, several population-based studies have attempted to estimate the burden of DR in low-resourced countries. Current estimates of the prevalence of any DR among people with diabetes in developing regions ranges from 19% in Bangladesh,[10] 17–22% in India,[11–13] 30.3% in Cambodia,[14] 37% in Iran,[15] 43.1% in rural China[16] and 63% in South Africa.[17] Many of these studies have demonstrated comparable rates to what is observed in developed nations such as Australia,[18] the UK[19] and the USA,[20] which have 29.3, 39 and 50.3% prevalence of DR, respectively, among those diagnosed with diabetes. This observation is contributed in part by the deficiency of robust epidemiological studies conducted in lower-income countries. One source of estimates of DR prevalence in developing regions has originated from Rapid Assessment of Avoidable Blindness surveys that are designed to estimate the prevalence and causes of blindness in people older than 50 years of age.[21] Given that the majority of patients with diabetes in developing regions fall within the 20–64 age group, this may therefore underestimate the true impact of DR.[9] In addition, there is a high proportion of undiagnosed diabetes in developing regions. This ranges from 52% in India,[22,23] to 62.8% in rural China, 66% in Cambodia,[24] 85% in sub-Saharan Africa, 70% in Ghana and 80% in Tanzania.[25] This compares with 25% in the UK,[26] 27% in the USA[27] and 50% in Australia.[28] Accordingly, estimates of projected growth of diabetes in India, sub-Saharan Africa, Asia and the islands, Latin America and the Middle East by the year 2030 are two- to threefold higher than that of established market economies.[9] Several excellent recent reviews have since highlighted the need to incorporate south Asian and Pacific islanders into the high-risk ethnic group category in order to prioritize screening of individuals in these regions.[29,30]

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