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 can not 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 .
BACKGROUND The Internet could provide a means of delivering secondary prevention programmes to people with coronary heart disease ( CHD ) .
OBJECTIVES To determine the effectiveness of Internet-based interventions targeting lifestyle changes and medicines management for the secondary prevention of CHD .
An Online Community Improves Adherence in an Internet-Mediated Walking Program. Part 1: Results of a Randomized Controlled Trial
Background Approximately half of American adults do not meet recommended physical activity guidelines . Face-to-face lifestyle interventions improve health outcomes but are unlikely to yield population -level improvements because they can be difficult to disseminate , expensive to maintain , and inconvenient for the recipient . In contrast , Internet-based behavior change interventions can be disseminated widely at a lower cost . However , the impact of some Internet-mediated programs is limited by high attrition rates . Online communities that allow participants to communicate with each other by posting and reading messages may decrease participant attrition . Objective Our objective was to measure the impact of adding online community features to an Internet-mediated walking program on participant attrition and average daily step counts . Methods This r and omized controlled trial included sedentary , ambulatory adults who used email regularly and had at least 1 of the following : overweight ( body mass index [ BMI ] ≥ 25 ) , type 2 diabetes , or coronary artery disease . All participants ( n = 324 ) wore enhanced pedometers throughout the 16-week intervention and uploaded step-count data to the study server . Participants could log in to the study website to view graphs of their walking progress , individually-tailored motivational messages , and weekly calculated goals . Participants were r and omized to 1 of 2 versions of a Web-based walking program . Those r and omized to the “ online community ” arm could post and read messages with other participants while those r and omized to the “ no online community " arm could not read or post messages . The main outcome measures were participant attrition and average daily step counts over 16 weeks . Multiple regression analyses assessed the effect of the online community access controlling for age , sex , disease status , BMI , and baseline step counts . Results Both arms significantly increased their average daily steps between baseline and the end of the intervention period , but there were no significant differences in increase in step counts between arms using either intention-to-treat or completers analysis . In the intention-to-treat analysis , the average step count increase across both arms was 1888 ± 2400 steps . The percentage of completers was 13 % higher in the online community arm than the no online community arm ( online community arm , 79 % , no online community arm , 66 % , P = .02 ) . In addition , online community arm participants remained engaged in the program longer than no online community arm participants ( hazard ratio = 0.47 , 95 % CI = 0.25 - 0.90 , P = .02 ) . Participants with lower baseline social support posted more messages to the online community ( P < .001 ) and viewed more posts ( P < .001 ) than participants with higher baseline social support . Conclusion Adding online community features to an Internet-mediated walking program did not increase average daily step counts but did reduce participant attrition . Participants with low baseline social support used the online community features more than those with high baseline social support . Thus , online communities may be a promising approach to reducing attrition from online health behavior change interventions , particularly in population s with low social support . Trial Registration NCT00729040 ; http:// clinical trials.gov/ct2/show/NCT00729040 ( Archived by WebCite at http://www.webcitation.org/5v1VH3n0A
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 can not 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 .
BACKGROUND The Internet could provide a means of delivering secondary prevention programmes to people with coronary heart disease ( CHD ) .
OBJECTIVES To determine the effectiveness of Internet-based interventions targeting lifestyle changes and medicines management for the secondary prevention of CHD .