Aiello 2015 (more‐frequent‐than‐annual follow‐ups).

Study characteristics
Methods	Assessing the effect of personalized diabetes risk assessments during ophthalmologic visits on glycaemic control: a randomized clinical trial Clustered RCT (25 clusters and 123 providers), conducted in 1) This randomised, multicentre clinical trial was conducted by the Diabetic Retinopathy Clinical Research Network at 42 clinical sites in the United States. 2) Point‐of‐care visits and education by ophthalmologists. In United States of America. 2 arms: 1) Control (usual care) (control arm) and 2) Intervention (visits and education by ophthalmologists) (intervention arm) 2 separate cohorts: participants were included in the cohort with more‐frequent‐than‐annual follow‐ups if at least 1 ophthalmologic visit occurred between baseline and 1 year, otherwise they were included in the cohort with annual follow‐ups
Participants	Control arm N: 502 Intervention arm N: 488, NA, NA Diabetes type: 3 Mean age: 64.49 ± NR % Male: 47.54 Longest follow‐up: 12 months
Interventions	Control arm: (usual care) Intervention arm: (visits and education by ophthalmologists) 1) Case management 2) Team change 3) Facilitated relay of clinical information 4) Patient education
Outcomes	1) Glycated haemoglobin
Funding source	This work was supported by a co‐operative agreement from the National Eye Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institutes of Health, and the US Department of Health and Human Services (grants EY14231, EY23207, and EY18817)
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported in text and in trial protocol (Supplement 1). Randomised in a 1:1 ratio, stratified by site or patient race/ethnicity.
Allocation concealment (selection bias)	Low risk	Clustered RCT.
Provider's baseline characteristics (selection bias)	Unclear risk	Not reported.
Patient's baseline characteristics (selection bias)	Low risk	Baseline characteristics by patient were similar between treatment groups and between cohorts (eTable 1 in Supplement 2).
Patient's baseline outcomes (selection bias)	Low risk	Means of HbA1c, arterial blood pressure and body mass index look similar at baseline between groups.
Incomplete outcome data (attrition bias)	High risk	Total of 264 patients lost out of 1746 at baseline (15%). The 1‐year visit completion rates (excluding deaths) were 88% and 89% in the control and intervention groups, respectively, for the cohort with more‐frequent‐than‐annual follow‐ups and 82% and 85% in the control and intervention groups, respectively, for the cohort with annual follow‐ups. Baseline characteristics were similar when comparing 1‐year completers with non‐completers (data not shown),with the exception of a higher mean central laboratory HbA1c level in the non‐completers of each cohort/group (8.7% vs 8.4% in non completers vs completers, overall).
Blinding of participants and personnel (performance bias) and of outcome assessors (detection bias)	Low risk	Our outcome of interest is objective (HbA1c).
Selective reporting (reporting bias)	Low risk	Prospectively registered protocol (protocol first posted on March 2011, enrollment was from April 2011 through January 2013, intervention of 12 months). Results match protocol.
Risk of contamination (other bias)	Low risk	Clustered‐RCT. However, the lack of an intervention effect in our study could reflect the standard care given by this specialised investigator group, which is highly attuned to evidence‐based retinal care for individuals with diabetes and possibly already providing patient education at a level where the prescribed intervention would not add incremental benefit.
Other bias	Low risk	No evidence of other bias