CENTRAL	Cochrane Central Register of Controlled Trials
CI	Confidence interval
DM	Diabetes mellitus
DR	Diabetic retinopathy
GRADE	Grading of Recommendations Assessment, Development and Evaluation
JBI	Joanna Briggs Institute
NHS	National Health Service
NOS	Newcastle–Ottawa Scale
OR	Odds ratio
PICo	Population–Interest–Context
PICO	Population–Intervention/Interest–Comparator–Outcome
PRISMA	Preferred Reporting Items for Systematic Reviews and Meta-Analyses
RoB 2	Risk of Bias 2
T1DM	Type 1 diabetes mellitus
T2DM	Type 2 diabetes mellitus
UK	United Kingdom