. 2023 Feb 22;2023(2):CD013775. doi: 10.1002/14651858.CD013775.pub2

6. Educational level ‐ Studies undertaking multivariable regression analyses to determine the effect of educational level on progression to PDR.

Study	Study type	Time years	N at baseline	Adjustment factors	Effect estimate			P value	Comments
					Type	Value	95% CI
Type 1 diabetes
WESDR Klein 1994	Prospective cohort	4	996	HbA1c, DR severity at baseline	OR	0.59^a 0.26^b	0.2 to 1.78 0.07 to 0.99		Per ≥ 5 years of education
Type 2 diabetes
WESDR Klein 1994	Prospective cohort	4	1370	HbA1c, DR severity at baseline	OR	0.50^a 0.90^b	0.21 to 1.16 0.33 to 2.48		Per ≥ 5 years of education

BMI: body mass index; CI: confidence interval; DBP: diastolic blood pressure; DM: diabetes mellitus; DR: diabetic retinopathy; HbA1c: glycated haemoglobin/haemoglobin A1c; HR: hazard ratio; NPDR: non‐proliferative diabetic retinopathy; OR: odds ratio; PDR: proliferative diabetic retinopathy; RR: risk ratio; SBP: systolic blood pressure; vs: versus

^aMales ^bFemales