Eleven RCTs (3,145 patients) were included in the review. Nine trials (3,010 patients) were telephone-based and two (135 patients) were Internet-based. Limited information was provided about trial quality; no trial was double-blind and all RCTs reported adequate concealment of allocation.
All-cause mortality: The telehealth intervention was associated with a non significant lower risk of death (RR 0.70, 95% CI 0.45 to 1.1; 11 RCTs).
Risk factors: The telehealth intervention was associated with a significantly lower total cholesterol (WMD 0.37mmol/L, 95% CI 0.19 to 0.56; eight RCTs); a significantly lower low-density lipoprotein cholesterol (WMD 0.41mmol/L, 95% CI 0.36 to 0.56; four RCTs); a significantly higher high-density lipoprotein cholesterol (WMD 0.05mmol/L, 95% CI 0.01 to 0.09; seven RCTs); a significantly lower systolic blood pressure (WMD 4.69mmHg, 95% CI 2.91 to 6.47; five RCTs); and a significantly lower risk of smoking (RR 0.83, 95% CI 0.70 to 0.99; seven RCTs). The telehealth intervention was associated with non significant lower triglycerides, lower body mass index and better levels of physical activity. No meta-analysis was conducted for physical activity due to the variation in assessment methods.
Significant heterogeneity and moderate heterogeneity were considered present for the outcomes of total cholesterol (I2 = 80%) and systolic blood pressure (I2 = 71%). A random-effects model was used for the analysis of total cholesterol.
Psychosocial status, nutritional status, quality of life, and costs were reported in narrative syntheses.