18. Albumin excretion rate ‐ Studies undertaking multivariable regression analyses to determine the effect of albumin excretion rate 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
Roy 2006	Prospective cohort	6	725	HbA1c, age, hypertension	OR	2.40	1.09 to 5.29	0.009	Microproteinuria
Porta 2001	Prospective cohort	7	2013	HbA1c, DM duration, DR severity at baseline, age of DM diagnosis < 12 years, DBP, waist‐to‐height ratio	Regression estimate	1.33	1.12 to 1.58	0.001	With increasing level
Type 2 diabetes
Kim 1998	Prospective cohort	5	56	HbA1c, DM duration, age, change in BMI	RR	1.34	0.31 to 5.82		With increasing level

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