A total of 33 studies were included (n=59,605, range 40 to 21,647, median 186) of which 32 were RCTs and 26 were accorded an ADA evidence grade A and six an ADA grade C; the uncontrolled study was graded C.
Smoking cessation (three studies, n=1,188): Two studies reported a significant change in at least one outcome. There were no significant improvements in either clinical outcomes or health status. All bar two behaviour outcomes yielded a significant improvement.
Eye examination (two studies, n=19,803): One of two studies showed a significantly greater improvement in the intervention group at six months and the other detected a significant improvement at 12 months.
Foot care (10 studies, n=7,739): All studies reported significant improvements for at least one outcome. Significant improvements were reported for numerous clinical and health status outcomes.
Oral health (two studies, n=209): For one study, significant improvements were observed in five clinical outcomes; no significant improvements in behaviour outcomes were observed in either study.
Vaccination (one study, n=21,647): A significant improvement in vaccination rate was observed for patient education signs and reminder stickers.
Cardiovascular risk reduction (nine studies, n=2,760): Five of 12 behaviour outcomes were associated with a significant improvement. Sixteen of 56 between-group clinical outcomes were associated with a significant improvement. Three of the six health outcomes considered had significant improvements. Four clinical measures showed significant improvement: HbA1c, serum cholesterol, systolic blood pressure and diastolic blood pressure.
Combined risk reduction (six studies, n=6,259): All studies showed a significant improvement in at least one outcome. Thirteen of 33 behaviour outcomes were associated with a significant improvement and 19 of 48 clinical outcomes were associated with a significant improvement.