Adding transcutaneous electrical nerve stimulation to routine physical therapy reduced movement-evoked pain compared with physical therapy alone among patients with fibromyalgia, with benefits sustained for six months, according to a cluster randomized clinical trial.

Movement-evoked pain is a key barrier to exercise participation in patients with fibromyalgia, despite exercise being a first-line treatment, wrote lead study author Dana L. Dailey, PT, PhD, of the University of Iowa, and colleagues.

The Fibromyalgia TENS in Physical Therapy Study (FM-TIPS) evaluated the effectiveness of transcutaneous electrical nerve stimulation (TENS) in real-world outpatient physical therapy settings, where treatment approaches and patient populations are more heterogeneous.

Study Details

The pragmatic trial was conducted across 28 outpatient clinics in six health care systems. A total of 459 patients were enrolled, with 384 included in the modified intention-to-treat analysis.

Clinics were randomized to provide physical therapy plus TENS (191 patients) or physical therapy alone (193 patients). Patients were followed for six months, with the primary end point assessed at 60 days.

TENS electrodes were applied to the upper and lower back, and patients were instructed to use the device for approximately 2 hours daily during activity at a strong but comfortable intensity.

Key Findings

Movement-evoked pain decreased more in the physical therapy plus TENS group compared with the physical therapy–alone group at 60 days, with a mean between-group difference of 1.2 points on a 0 to 10 scale—a reduction that met the threshold for a clinically meaningful improvement.

Additional findings included:

• 41% of patients receiving TENS achieved at least a 30% reduction in movement-evoked pain vs 13% in the physical therapy–alone group

• 72% vs 51% reported improvement on the Patient Global Impression of Change

• Improvements were observed by 30 days and sustained through 180 days

• Secondary outcomes favored physical therapy plus TENS, including statistically significant reductions in resting pain, movement-evoked and resting fatigue, pain interference, and overall disease impact at 60 days

After crossover to TENS following day 60, patients initially assigned to physical therapy alone experienced similar improvements. A dose-response relationship was observed, with greater TENS use associated with larger reductions in movement-evoked pain.

No serious adverse events related to TENS were reported. Minor adverse events occurred in about 30% of patients and included discomfort, skin irritation, itchiness, anxiety, and nausea.

Commentary: Modest Benefit, Questions About Physical Therapy Alone

In an invited commentary, Afton L. Hassett, PsyD, and Daniel J. Clauw, MD, both of the University of Michigan, noted that the findings support TENS as an additional nonpharmacologic option but emphasized that the magnitude of benefit was modest.

They highlighted that patients receiving physical therapy alone showed little to no improvement in movement-evoked pain or most secondary outcomes. The commentators suggested this may reflect the nonstandardized nature of physical therapy in the trial, which was not necessarily tailored to fibromyalgia.

They noted that prior studies of physical therapy and exercise in fibromyalgia have typically used regimens specifically tailored to the condition, often employing a “start low and go slow” approach. In contrast, they wrote that physical therapy delivered without such tailoring may sometimes worsen rather than improve pain.

They also noted that the approximately 1.2-point reduction in pain raises the possibility that some of the observed effect could be due to regression to the mean, although improvements seen after crossover to TENS support a true treatment effect.

Overall, they concluded that TENS appears to provide small to moderate improvements in pain and related symptoms and represents a useful addition to the limited number of effective nonpharmacologic therapies for fibromyalgia.

Insights and Limitations

The researchers reported several limitations, including the inability to assess changes in medication use, underrepresentation of racial and ethnic minority populations, and variability in physical therapy approaches, which were not standardized or necessarily tailored to fibromyalgia.

They noted that the pragmatic design enhances generalizability but may contribute to smaller effect sizes compared with prior controlled trials.

The researchers concluded that TENS “produced effects quickly, remained effective through 6 months, and continued to be helpful to most study participants,” adding that it should be considered a safe treatment option for fibromyalgia.

Disclosures

The study was supported by the National Institutes of Health. One investigator reported payments to a private practice during the study, another reported grant support during the study, and two investigators reported personal fees outside the submitted work; no other disclosures were reported.

Source: JAMA Network