Gui 2013.

Study characteristics
Methods	Study design: retrospective cohort Location: China Time period: Recruitment: 1 January 2009 to 1 January 2010 Follow‐up: January to May 2012 Outcome: PDR Outcome measurement: cumulative incidence, OR, means and percentages of progressors versus non‐progressors to PDR
Participants	Number of participants: 205 Diabetes type: T2D Inclusion criteria: T2D; NPDR Exclusion criteria: not reported
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/psj4v/?view_only=70ca392da5cb4d7cb069361dbb4eda03
Item	Authors' judgement	Support for judgement
Study participation	Unclear	See ‘Notes’ above for link to risk of bias assessment
Study attrition	Unclear	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