High prevalence in Malawi of sight‐threatening retinopathy and visual impairment caused by diabetes: identification of population‐specific targets for intervention

Abstract

AimsTo report the prevalence of all grades of diabetic retinopathy and associations with demographic, clinical and biochemical variables in people with diabetes in Southern Malawi.MethodsWe report baseline data from a 24-month prospective cohort study. Subjects were systematically sampled from two hospital-based, primary care diabetes clinics. Visual acuity, glycaemic control, systolic blood pressure, HIV status, urine albumin–creatinine ratio, and haemoglobin and serum lipid levels were assessed. Retinopathy was graded at an accredited reading centre using modified Wisconsin grading of four-field mydriatic photographs.ResultsA total of 357 subjects were studied. Of these, 13.4% subjects were HIV-positive and 15.1% had anaemia. The overall prevalence rates of any retinopathy, sight-threatening diabetic retinopathy and proliferative retinopathy were 50.1% (95% CI 44.9–55.3), 29.4% (95% CI 24.7–34.1) and 7.3% (95% CI 4.6–10.0), respectively. In multivariate logistic analysis the presence of sight-threatening retinopathy was associated with duration of diabetes (odds ratio 1.11, 95% CI 1.05–1.17), HbA1c (odds ratio 1.31, 95% CI 1.13–1.50), systolic blood pressure (odds ratio 1.03, 95% CI 1.01–1.04), haemoglobin (odds ratio 0.98, 95% CI 0.96–0.99) and LDL cholesterol (odds ratio 1.63, 95% CI 1.18–2.25). No significant association with HIV status was observed. In all, 3.6 and 1.4% of people in our study cohort had visual acuity worse than 6/18 and 6/60 in the better eye, respectively.ConclusionsThe present study found a prevalence of sight-threatening retinopathy in diabetes clinics in one Sub-Saharan African country of approximately four times that reported in recent European studies and a prevalence of proliferative retinopathy approximately 10 times higher. The association of sight-threatening retinopathy with lower haemoglobin level is a new finding. Our results highlight the urgent need for provision of services for retinopathy detection and management to avoid a large burden of vision loss.

Incidence and progression of diabetic retinopathy in Sub-Saharan Africa: A five year cohort study

“…Of 34 subjects without STDR at baseline (2007) and seen at 7 years 12 (35.3%; 19.2–51.4) had developed the condition at 7 years. Fig 2 and S3 Fig combine data from our 24 month cohort study performed between 2012 and 2014 and published elsewhere [ 14 , 15 ], 5 year progression data detailed in this manuscript and 6 and 7 year data from the 41 subjects described above to give a composite graph of DR progression over 7 years.…”

“…Clinical assessment of subjects in 2012 was the same as in our 24 month cohort study described in detail elsewhere [ 14 ]. Briefly, uncorrected and pinhole visual acuity was assessed using an Early Treatment of Diabetic Retinopathy Study (ETDRS) chart.…”

“…Additionally, we undertook a prospective, 2 year cohort study of patients attending two hospital-based diabetes clinics. Data from this study has been published elsewhere [ 14 , 15 ].…”

First Prospective Cohort Study of Diabetic Retinopathy from Sub-Saharan Africa

“…Conversely, those with established complications may be more likely to attend clinics and participate in research studies. The MDRS included few subjects with diet-controlled diabetes because few of these attend the diabetic clinic 14 . Although some patients travel long distances to attend clinics, rural subjects are likely to represent a selected subgroup of the rural diabetic population.…”

“…Clinical assessment of subjects in the MDRS has been described 14 . Briefly, visual acuity (VA) (uncorrected and using pinhole) was measured as the number of letters read on a standard Early Treatment of Diabetic Retinopathy Study (ETDRS) chart.…”