Sixteen studies (108,414 participants) were included in the review; 14 studies used observational designs. Eleven studies were rated as good quality, three were rated fair and two were poor. Nine studies reported referral rates and six reported uptake rates.
The percentage of the screening populations referred to their practitioner varied widely across studies (Ι²=99.9%) with estimates that ranged from 6.05% (95% CI 3.54 to 10.13) to 72.97% (95% CI 69.39 to 76.27). There was a strong trend towards higher referral rates in more recently published studies.
The percentage uptake of a referral to a general practitioner also varied widely (Ι²=99.5%), with estimates that ranged from 12.81% (95% CI 12.11 to 13.54) to 92.31% (95% CI 60.94 to 98.93).
The percentage of individuals who exceeded cut offs for different risk factors (diabetes, hypercholesterolaemia and hypertension) were similarly inconsistent across studies.