3. Age at diagnosis of diabetes ‐ Studies undertaking multivariable regression analyses to determine the effect of age at diagnosis of diabetes on progression to PDR.
| Study | Study type | Time years | N at baseline | Adjustment factors | Effect estimate | P value | ||
| Type | Value | 95% CI | ||||||
| Type 1 diabetes | ||||||||
| Porta 2001 | Prospective cohort | 7 | 2013 | HbA1c, DM duration, severity at baseline, DBP > 83 mmg DR, waist‐to‐hip ratio | Standardised regression estimate | 1.62 | 1.06 to 2.48 | 0.038a |
| Type 2 diabetes | ||||||||
| Gange 2021 | Prospective cohort (electronic database) | 5 | 718 | Maximum HbA1c, gender, smoking, comorbidities, obesity, insulin use, education, hypertension, dyslipidaemia, diabetic ketoacidosis | OR | 0.46b 1.25c 1.62d 1.30e |
0.29 to 0.74 1.05 to 1.48 1.28 to 2.03 1.00 to 1.68 |
0.001 0.012 < 0.001 0.048 |
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; vs: versus
aEffect did not remain significant when albumin excretion rate included as a covariate b18 to 34 years vs 45 to 54 years c55 to 64 years vs 45 to 54 years d65 to 74 years vs 45 to 54 years e≥75 years vs 45 to 54 years