Prevalence of diabetes and diabetic retinopathy among adults aged 50 years and above in Nepal: a population-based cross-sectional survey.

Background: Diabetic retinopathy (DR), a microvascular complication of diabetes mellitus (DM), is a leading cause of vision loss worldwide. There is limited national data to inform about the prevalence of DM and DR and its associated factors, which led to the basis of conducting this survey, which would guide us for the same as part of the Rapid Assessment of Avoidable Blindness (RAAB) survey conducted across Nepal.

Methods: A population-based cross-sectional RAAB survey was conducted using multistage cluster random sampling. RAAB+DR methodology was conducted between June 2019 and February 2021 among individuals aged≥50 years across selected provinces. Diabetes was diagnosed based on treatment history and random blood glucose test with level>200 mg/dL, while DR was graded by trained ophthalmologists. All relevant data were imported into the RAAB software to determine the prevalence of DM, DR and associated factors.

Results: Among the 13 510 participants examined, the prevalence of DM was found to be 6.1% which was higher in Bagmati province at 9.4% (95% CI: 8.2% to 10.7%). Prevalence of DM was higher among females, but DR was more common in males in rural areas and females in urban areas. Untreated diabetes was most common in Madhesh (35.1%). DR prevalence was highest in Bagmati (15.9%; 95% CI: 12.7% to 19.1%), and 2.5% (95% CI: 1.2% to 3.8%) of those patients had sight-threatening DR. In Bagmati, 24.1% of diabetics had never undergone an eye examination.

Conclusion: The limited coverage of DR screening underscores the need for enhanced community-based DR screening and referral programmes. Our study lacked the use of plasma blood glucose level measurement to diagnose DM, proper slit lamp examination for diabetic retinopathy grading and diagnosis, and inclusion of a younger population providing a better representation. Strengthening these initiatives can prevent vision-threatening complications in underserved populations.