Abstract: Eighteen trials met our inclusion criteria. Eleven studies are complete (1392 participants), and seven are ongoing. Of the completed studies, seven interventions are broad, targeting the lifestyle management of CHD, and four focused on physical activity promotion. The comparison group in trials was usual care (n = 6), minimal intervention (n = 3), or traditional cardiac rehabilitation (n = 2). We found no effects of Internet-based interventions for all-cause mortality (odds ratio (OR) 0.27, 95% confidence interval (CI) 0.04 to 1.63; participants = 895; studies = 6; low-quality evidence). There was only one case of cardiovascular mortality in a control group (participants = 895; studies = 6). No incidences of non-fatal re-infarction were reported across any of the studies. We found no effects for revascularisation (OR 0.69, 95% CI 0.37 to 1.27; participants = 895; studies = 6; low-quality evidence). We found no effects for total cholesterol (mean difference (MD) 0.00, 95% CI -0.27 to 0.28; participants = 439; studies = 4; low-quality evidence), high-density lipoprotein (HDL) cholesterol (MD 0.01, 95% CI -0.06 to 0.07; participants = 437; studies = 4; low-quality evidence), or triglycerides (MD 0.01, 95% CI -0.17 to 0.19; participants = 439; studies = 4; low-quality evidence). We did not pool the data for low-density lipoprotein (LDL) cholesterol due to considerable heterogeneity. Two out of six trials measuring LDL cholesterol detected favourable intervention effects, and four trials reported no effects. Seven studies measured systolic and diastolic blood pressure; we did not pool the data due to substantial heterogeneity. For systolic blood pressure, two studies showed a reduction with the intervention, but the remaining studies showed no effect. For diastolic blood pressure, two studies showed a reduction with the intervention, one study showed an increase with the intervention, and the remaining four studies showed no effect. Five trials measured health-related quality of life (HRQOL). We could draw no conclusions from one study due to incomplete reporting; one trial reported no effect; two studies reported a short- and medium-term effect respectively; and one study reported both short- and medium-term effects. Five trials assessed dietary outcomes: two reported favourable effects, and three reported no effects. Eight studies assessed physical activity: five of these trials reported no physical activity effects, and three reported effectiveness. Trials are yet to measure the impact of these interventions on compliance with medication. Two studies measured healthcare utilisation: one reported no effects, and the other reported increased usage of healthcare services compared to a control group in the intervention group at nine months' follow-up. Two trials collected cost data: both reported that Internet-delivered interventions are likely to be cost-effective. In terms of the risk of bias, the majority of studies reported appropriate randomisation and appropriate concealment of randomisation processes. A lack of blinding resulted in a risk of performance bias in seven studies, and a risk of detection bias in five trials. Two trials were at risk of attrition bias, and five were at risk for reporting bias. In general, evidence was of low quality due to lack of blinding, loss to follow-up, and uncertainty around the effect size. Few studies measured clinical events, and of those that did, a very small number of events were reported, and therefore no firm conclusions can be made. Similarly, there was no clear evidence of effect for cardiovascular risk factors, although again the number of studies reporting these was small. There was some evidence for beneficial effects on HRQOL, dietary outcomes, and physical activity, although firm conclusions cannot yet be made. The effects on healthcare utilisation and cost-effectiveness are also inconclusive, and trials are yet to measure the impact of Internet interventions on compliance with medication. The comparison groups differed across trials, and there were insufficient studies with usable data for subgroup analyses. We intend to study the intensity of comparison groups in future updates of this review when more evidence is available. The completion of the ongoing trials will add to the evidence base.

Plain-language summary: The evidence is current to December 2014. We included 18 studies. Eleven are complete, and seven are ongoing. In the completed studies, 1392 people with coronary heart disease were recruited. The average age of participants ranged from 54.9 to 66.27 years. The majority of people recruited were men. Studies were carried out worldwide, and in a variety of healthcare settings. Seven studies tested broad programmes targeting multiple lifestyle factors related to heart disease. Four studies tested programmes focused only on increasing levels of physical activity. The length of the programmes in the included studies ranged from six weeks to one year. These programmes were compared to no intervention in six studies, some support in three studies, and full traditional rehabilitation in two studies. There is no evidence to date to suggest that Internet-delivered programmes help reduce rates of death or future cardiac surgery, but this was based on a small number of studies. There is also no strong evidence to date suggesting a benefit of these programmes for lipid levels or blood pressure. There is some evidence to suggest improvements in HRQOL and behaviour change, but there is insufficient evidence to date to draw firm conclusions. Studies have not yet measured the impact of Internet-delivered programmes on medication compliance. There was very limited information on healthcare utilisation and cost of interventions. The reporting of the seven ongoing studies will add to the evidence base. The evidence was generally of low quality. The included studies were at some risk of bias, with six studies judged at high risk of bias for some risk of bias domains. The results of this review therefore need to be interpreted cautiously. There is currently limited evidence on the effects of Internet-based interventions for the treatment of coronary heart disease. We identified seven ongoing trials, which we will incorporate into this review when the results are available.