A recent study published in the British Journal of Ophthalmology assessed the impact of biennial versus annual screening to detect sight-threatening diabetic retinopathy (STDR) and proliferative diabetic retinopathy (PDR) in people living with diabetes (PLD) without DR.
Give me some background first.
As an ocular complication of diabetes that can potentially result in vision loss, early detection and treatment of DR is a crucial objective for many public health entities.
Since 2016, the UK National Screening Committee (NSC) has recommended annual eye screening for DR in PLD at high risk of sight loss and biennial screening for those at low risk of sight loss.
Tell me more about this recommendation.
This recommendation was implemented based on a retrospective audit commissioned by the NSC, where they found the risk of progression to referable DR was low (~0.7% per year), and that cases would still be treatable if delayed.
However, the effects of biennial screening by ethnicity and different age groups were not explicitly quantified, which, in part, motivated the study authors to further elucidate this relationship.
Now, talk about the study.
The National Health Service’s (NHS) Diabetic Screening Programme (DESP) offers PLD annual screening for DR to aid in early assessment and intervention.
Investigators analyzed the DESP data from January 2012 to December 2021 of PLD in North-East London with no DR on two prior consecutive screening visits and up to 8 years of follow-up.
What was the ethnic diversity of the cohort?
Of the total 82,782 people included in the study, the breakdown by ethnicity was as follows:
- 37% White
- 36% South Asian
- 16% Black
Findings?
There were 1,788 incident STDR cases over a mean of 4.3 years (STDR rate 0.51, 95% confidence interval [CI] 0.47-0.55 per 100-person-years).
STDR incidence rates per 100-person-years by ethnicity were:
- Black: 0.77 (95% CI 0.65-0.90)
- South Asian: 0.55 (95% CI 0.48-0.62)
- White: 0.34 (95% CI 0.29-0.40)
What about the incidence rate of STDR by age group?
A greater risk of developing STDR was reported in younger age groups (<45 years) and in older age groups, especially those aged 55 to <65 years.
How did biennial screenings impact DR detection rates?
Biennial screening would have delayed diagnosis by 1 year for 56.3% (1,007/1,788) of patients with STDR and 43.6% (45/103) of patients with PDR.
The standardized cumulative rates of delayed STDR per 100,000 persons for each ethnic group were:
- Black: 1,904 (95% CI 1,683-2,154)
- South Asian: 1,276 (95% CI 1,153-1,412)
- White: 844 (95% CI 745-955)
Expert opinion?
According to the study authors, “Alternatively, artificial intelligence (AI) technologies could be used to assist in maintaining the current status quo in screening frequency.”
They added that, while the effectiveness of AI has been demonstrated, “quantifying equity of AI performance across different ethnic and age groups is needed—akin to formally assessing the potential impact of a biennial screening program in different sociodemographic groups carried out in this study.”
Take home.
These findings show that biennial screening would have delayed the detection of some patients with STDR and PDR by 1 year, especially in Black patients, exacerbating existing healthcare inequalities.
Next steps?
The study authors proposed that in order to provide more equitable healthcare, alternative technologies (i.e., AI) that simplify the process of annual screening of PLD could be implemented, or more detailed screening intervals could be established for different sociodemographic groups.