Harris 2013.

Study characteristics
Methods	Study design: registry data Location: USA Time period: 01 January 2001 to 31 December 2009 Outcome: PDR Outcome measurement: incidence, means, and percentages of progressors versus non‐progressors to PDR, and HR
Participants	Number of participants: 4617 Diabetes type: T1D and T2D Inclusion criteria: new diagnosis of NPDR after first year in registry (point of baseline); aged ≥ 30 years; ≥ 2 registrations as having diagnosis of DM; continuous enrolment in registry; ≥ 1 visit to an ophthalmologist or optometrist during first year of registration and no signs of NPDR or PDR; ≥ 1 record of HbA1c following baseline date Exclusion criteria: in registry < 1 year; not in registry continuously; any record of PDR prior to index date
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/t52qu/?view_only=37b711fa179d4b249d9d16c430ec169e
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	Unclear	See ‘Notes’ above for link to risk of bias assessment