Kalter‐Leibovici 1991.

Study characteristics
Methods	Study design: prospective cohort longitudinal Location: Israel Time period: not reported Outcome: PDR Outcome measurement: incidence, OR, and median and percentages of progressors versus non‐progressors to PDR
Participants	Number of participants: 330 Diabetes type: T1D Inclusion criteria: all Jewish patients attending centre with early‐onset IDDM before 30 years of age and DM duration of ≥ 10 years Exclusion criteria: not reported
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/tz8bc/?view_only=5d94c5615d7847418d616db8f0ddd107
Item	Authors' judgement	Support for judgement
Study participation	Unclear	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