Study design: Observational study nested within a randomized controlled trial.
Objective: To evaluate the feasibility of using short message service (SMS) within a clinical trial of low back pain.
Summary of background data: Technological advances have transformed communication technologies and opened the way for their use in clinical studies. SMSs have been tested for use in data collection for different patient groups, but little is known about use of this technology in low back pain research.
Methods: Trial participants who owned a mobile phone and knew how to send SMS messages were included in the study. The participants were sent an SMS message asking them to rate their average pain, once a month for 12 consecutive months. Response rates during the year were calculated, and regression analyses were used to explore factors associated with phone ownership and response rates.
Results: Of the 133 participants in the trial, 105 (61.1%) had mobile phones and 97 (56.4%) knew how to use SMS. The regression analyses showed that older patients were less likely to own a mobile phone (P < 0.000). Response rates to SMS alone during the 12 months ranged from 54.8% to 74.2%, and for SMS supplemented with phone interviews ranged from 91.5% to 99%. The median (interquartile range) number of the scheduled 12 assessments completed by SMS per patient was 9 (interquartile range, 5-11). The Poisson regression revealed no significant effect for any of the predictors studied: age, sex, education level, and pain level at baseline and after treatment (P ≥ 0.16).
Conclusion: SMS supplemented with phone interviews, but not SMS alone, is a feasible option to collect simple data within a back pain clinical trial setting.