By Thomas Webb, Judith Joseph, Lucy Yardley, Susan Michie
J Med Internet Res 2010 (Feb 17); 12(1):e4
Background: The Internet is increasingly used as a medium for the delivery
of interventions designed to promote health behavior change. However,
reviews of these interventions to date have not systematically identified
intervention characteristics and linked these to effectiveness. Objectives:
The present review sought to capitalize on recently published coding frames
for assessing use of theory and behavior change techniques to investigate
which characteristics of Internet-based interventions best promote health
behavior change. In addition, we wanted to develop a novel coding scheme for
assessing mode of delivery in Internet-based interventions and also to link
different modes to effect sizes. Methods: We conducted a computerized search
of the databases indexed by ISI Web of Knowledge (including BIOSIS Previews
and Medline) between 2000 and 2008. Studies were included if (1) the primary
components of the intervention were delivered via the Internet, (2)
participants were randomly assigned to conditions, and (3) a measure of
behavior related to health was taken after the intervention. Results: We
found 85 studies that satisfied the inclusion criteria, providing a total
sample size of 43,236 participants. On average, interventions had a
statistically small but significant effect on health-related behavior (d+ =
0.16, 95% CI 0.09-0.23). More extensive use of theory was associated with
increases in effect size (P = .049), and, in particular, interventions based
on the theory of planned behavior tended to have substantial effects on
behavior (d+ = 0.36, 95% CI 0.15-0.56). Interventions that incorporated more
behavior change techniques also tended to have larger effects compared to
interventions that incorporated fewer techniques (P < .001). Finally, the
effectiveness of Internet-based interventions was enhanced by the use of
additional methods of communicating with participants, especially the use of
short message service (SMS), or text, messages. Conclusions: The review
provides a framework for the development of a science of Internet-based
interventions, and our findings provide a rationale for investing in more
intensive theory-based interventions that incorporate multiple behavior
change techniques and modes of delivery.
TEXTO COMPLETO DESDE AQUI