[Process and outcome of an internet-based preparation for inpatient psychosomatic psychotherapeutic treatment: an examination of website use].

Objective: A main challenge for evaluating online intervention is to identify which elements are used and to identify participants who are more engaged.

Methods: The study analyzes data on intervention use of an Internet-based preparation for inpatient psychosomatic psychotherapeutic treatment (VORSTAT).

Results: Data were available for 176 participants enrolled into VORSTAT from July 2009 to February 2011. The utilization of the program turned out to be very different across the users. Those who used all program features reported at registration more severe impairment, lived further away from the hospital, and had a longer waiting period. Regarding treatment outcome no differences between high and low utilizers were found.

Conclusion: The exploration of process characteristics is critical in the evaluation of Internet-based applications and improved knowledge about individual's usage of online interventions enable us to better tailor therapy according to the individual patients' characteristics and hopefully enhance the efficacy.