Mathiesen 1990.

Study characteristics
Methods	Study design: prospective cohort Location: Denmark Time period: recruitment: October 1982 to January 1983; follow‐up: January 1988 Outcome: PDR Outcome measurement: incidence
Participants	Number of participants: 209 Diabetes type: T1D Inclusion criteria: age 18 to 50 years; onset of IDDM before 30 years; duration of diabetes 10 to 30 years; regular attendance in outpatient clinic at Steno Diabetes Centre; diastolic blood pressure < 100 mmHg; sterile urine with normal urinary microscopy; urine albumin excretion (UAE) < 30 mg/24 hours in one 24‐hour urine sample collected at home; during the first year of observation, at least 2 of 3 UAE tests had to be within normal range to secure an observation period with normoalbuminuria Exclusion criteria: not reported
Notes	Link to data extraction table, risk of bias assessment, and results: osf.io/3hk45/?view_only=9f362bec79d6448ab00f9dccff055bba
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	No	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