THU0490 PREDICTORS OF CHRONIC PAIN RELIEF BY FIXED-SITE HIGH-FREQUENCY TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION

Abstract

Fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) is a form of TENS in which the stimulator is designed for a predetermined location rather than for colocalization with the patient's pain. A single target site enables design of small wearable devices that may be used while active and sleeping. Previous studies have demonstrated that 50-80% of FS-TENS users with chronic lower extremity or low back pain experience clinically meaningful pain relief. The objective of this study was to determine predictors of a positive FS-TENS response. This retrospective, observational study evaluated users of an FS-TENS device to treat chronic pain over a 10- week period. The device and companion smartphone app collect dosage data, demographics, pain characteristics, and pain ratings that are stored in a cloud database. The primary study outcome was the baseline to 10-week change in composite pain (average of pain intensity and pain interference with sleep, activity, and mood). Device users were included if they provided demographic data, pain characteristics indicative of chronic pain, and baseline and 10-week pain ratings. Participants were defined as a responder or comparator based on their change in composite pain (responder ≥15% decrease, comparator ≥15% increase). Stepwise forward probit regression was used to determine independent predictors. There were 451 responders and 263 comparators. Independent predictors were age, baseline composite pain, adherence, stimulation intensity, no headaches/migraine, no diabetes, and no weather sensitivity. The area under the receiver operating characteristic curve was 0.76 (95% confidence interval = 0.72-0.79). FS-TENS effectiveness was predicted from baseline pain characteristics and dosage variables with moderate accuracy.