BACKGROUND: Internet-based interventions are increasingly used to support 
self-management of individuals with chronic illnesses. Web-based interventions 
may also be effective in enhancing self-management for individuals with chronic 
pain, but little is known about long-term effects. Research on Web-based 
interventions to support self-management following participation in pain 
management programs is limited.
OBJECTIVE: The aim is to examine the long-term effects of a 4-week 
smartphone-intervention with diaries and therapist-written feedback following an 
inpatient chronic pain rehabilitation program, previously found to be effective 
at short-term and 5-month follow-ups.
METHODS: 140 women with chronic widespread pain, participating in a 4-week 
inpatient rehabilitation program, were randomized into two groups: with or 
without a smartphone intervention after the rehabilitation. The smartphone 
intervention consisted of one face-to-face individual session and 4 weeks of 
written communication via a smartphone, consisting of three diaries daily to 
elicit pain-related thoughts, feelings, and activities, as well as daily 
personalized written feedback based on cognitive behavioral principles from a 
therapist. Both groups were given access to an informational website to promote 
constructive self-management. Outcomes were measured with self-reported 
paper-and-pencil format questionnaires with catastrophizing as the primary 
outcome measure. Secondary outcomes included daily functioning and symptom 
levels, acceptance of pain, and emotional distress.
RESULTS: By the 11-month follow-up, the favorable between-group differences 
previously reported post-intervention and at 5-month follow-up on 
catastrophizing, acceptance, functioning, and symptom level were no longer 
evident (P>.10). However, there was more improvement in catastrophizing scores 
during the follow-up period in the intervention group (M=-2.36, SD 8.41) 
compared to the control group (M=.40, SD 7.20), P=.045. Also, per protocol 
within-group analysis showed a small positive effect (Cohen's d=.33) on 
catastrophizing in the intervention group (P=.04) and no change in the control 
group from the smartphone intervention baseline to 11-month follow-up. A 
positive effect (Cohen's d=.73) on acceptance was found within the intervention 
group (P<.001) but not in the control group. Small to large negative effects 
were found within the control group on functioning and symptom levels, emotional 
distress, and fatigue (P=.05) from the intervention baseline to the 11-month 
follow-up.
CONCLUSION: The long-term results of this randomized trial are ambiguous. No 
significant between-group effect was found on the study variables at 11-month 
follow-up. However, the within-group analyses, comparing the baseline for the 
smartphone intervention to the 11-month data, indicated changes in the desired 
direction in catastrophizing and acceptance in the intervention group but not 
within the control group. This study provides modest evidence supporting the 
long-term effect of the intervention.
TRIAL REGISTRATION: Clinicaltrials.gov NCT01236209; 
http://www.clinicaltrials.gov/ct2/show/NCT01236209 (Archived by WebCite at 
http://www.webcitation.org/6FF7KUXo0).