Janghorbani 2000.

Study characteristics
Methods	Study design: retrospective cohort Location: UK Time period: 1979 to 1992 Outcome: PDR Outcome measurement: incidence, RR, and mean difference between progressors and non‐progressors to PDR
Participants	Number of participants: 3482 Diabetes type: T1D and T2D Inclusion criteria: NIDDM or IDDM; free of PDR (including those with no retinopathy and those with NPDR at registration); complete data available Exclusion criteria: secondary diabetes; type of diabetes unknown
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/3xfrg/?view_only=baa50019fd8b4a1898e78ad977ed9398
Item	Authors' judgement	Support for judgement
Study participation	Yes	See ‘Notes’ above for link to risk of bias assessment
Study attrition	No	See ‘Notes’ above for link to risk of bias assessment
Prognostic factor measurement	Unclear	See ‘Notes’ above for link to risk of bias assessment
Outcome measurement	Unclear	See ‘Notes’ above for link to risk of bias assessment
Adjustment for other prognostic factors	Unclear	See ‘Notes’ above for link to risk of bias assessment
Statistical analysis and reporting	Yes	See ‘Notes’ above for link to risk of bias assessment