Diabetic retinopathy in Sub-Saharan Africa: prevalence and regional variations from a systematic review and meta-analysis
Bibliographic record
Abstract
Background Diabetic retinopathy (DR) is a prevalent microvascular complication of diabetes mellitus and a significant cause of blindness worldwide, In Sub-Saharan Africa (SSA), the epidemic of diabetes is rapidly expanding, with hundreds of millions expected by 2045, and DR is approximated to afflict about one-third of individuals with diabetes in the region Nevertheless, the total burden of DR in SSA has not been methodically estimated. Objective We sought to estimate the pooled prevalence of DR in adults with diabetes in SSA and investigate sources of variation. Methods We performed a systematic review and meta-analysis according to PRISMA 2020 guidelines. We searched PubMed, AJOL, Google Scholar, and other sources through mid-2024 for observational studies (cross-sectional or cohort) that reported DR prevalence in adults with diabetes in SSA. Two reviewers screened records, extracted data (study, country, design, sample size, DR cases), and evaluated quality using the JBI checklist. Random-effects meta-analysis (logit transformation) estimated pooled prevalence and 95% confidence intervals (CI), Heterogeneity was measured by Cochran’s Q and I2, and τ2 was reported. Subgroup meta-analysis by region (East, West, Central, and Southern Africa) and meta-regression by country (fixed categorical moderator) were conducted. Funnel plots and Egger’s test (p < 0.05) examined publication bias. Results We pooled 30 studies (N = 16,329 individuals) from 18 SSA countries, Most were hospital-based and cross-sectional; no study was excluded due to high bias. The overall pooled prevalence of DR among individuals with diabetes was 25.5% (95% CI: 20.7%–31.0%) (Logit = −1.072, 95% CI −1.345 to −0.799; p < 0.001). Heterogeneity was very high (I2 ≈ 96%, τ2 = 0.433). Subgroup analysis revealed differences by sub region: East Africa 31.8%, Southern Africa 29.6%, West Africa 27.4%, and Central Africa 13.7%. A meta-regression with country as moderator was not statistically significant (F = 0.94, p = 0.560). Egger’s test demonstrated significant asymmetry (p < 0.001), although the weighted regression test was no significant (p = 0.154), which suggests potential publication bias. Conclusion About a quarter of diabetics in SSA have DR. This is similar to regional estimates (28% in East Africapubmed.ncbi.nlm.nih.gov) but slightly lower than the overall Africa average (~36%)pubmed.ncbi.nlm.nih.gov. The high heterogeneity suggests that the prevalence of DR is highly variable throughout SSA. Restricted access to eye care, late diagnosis, and inadequate glycemic control in SSA are probably responsible for this, these findings highlight the urgent need for systematic diabetic retinopathy screening and management programs in sub-Saharan Africa.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.019 | 0.039 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.015 | 0.037 |
| Bibliometrics | 0.010 | 0.012 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".