Table 1.
Demographic and baseline clinical characteristics of the study participantsa
| Active TENS (n = 103) | Placebo TENS (n = 99) | No TENS (n = 99) | |
|---|---|---|---|
| Demographic variablesb | |||
| Age, years | 44.7 ± 14.3 | 47.2 ± 12.6 | 48.6 ± 11.8 |
| White race, % | 92 | 92 | 92 |
| Ethnicity, not Hispanic, % | 95 | 95 | 95 |
| Married/living with partner, % | 33c | 51 | 52 |
| Less than college graduate, % | 61 | 61 | 64 |
| Working, % | 55 | 45 | 58 |
| Health variables | |||
| Never smoked, % | 82 | 80 | 70 |
| Body mass index, kg/m2 | 34.8 ± 8.7 | 33.7 ± 8.8 | 34.0 ± 8.9 |
| Duration of fibromyalgia, median (range) years | 7 (3–12) | 7 (2–14) | 7 (4–15) |
| Opioid use for paind, no. (%) | 27 (26) | 26 (26) | 26 (26) |
| Baseline measures | |||
| Pain with movement during 6MWT (0–10) (primary outcome measure) | 6.5 ± 1.9 | 6.2 ± 1.9 | 6.4 ± 1.9 |
| Pain with movement during 5STS (0–10) (primary outcome measure) | 5.8 ± 2.4 | 5.5 ± 2.2 | 5.6 ± 2.2 |
| Pain at rest, NRS (0–10) | 6.2 ± 1.5 | 5.9 ± 1.4 | 6.1 ± 1.6 |
| Fatigue at rest, NRS (0–10) | 6.8 ± 2.0 | 6.1 ± 1.8 | 6.4 ± 2.0 |
| Revised FIQ pain score (0–10) | 6.7 ± 1.8e | 6.0 ± 1.6 | 6.15 ± 1.8 |
| Revised FIQ disease impact score (0–100) | 59.2 ± 16.8f | 53.7 ± 15.9 | 55.6 ± 16.0 |
| Mental quality of life (SF‐36 mental composite score, T score) | 38.7 ± 10.0 | 40.2 ± 10.2 | 39.5 ± 10.6 |
| Physical quality of life (SF‐36 physical composite score, T score) | 32.7 ± 6.4 | 33.3 ± 6.2 | 32.7 ± 6.6 |
| Pain catastrophizing (PCS, 0–52) | 23.1 ± 13.0 | 20.4 ± 12.5 | 20.8 ± 12.1 |
| Self‐efficacy (PSEQ, 0–60) | 28.2 ± 13.3 | 29.9 ± 13.1 | 29.0 ± 13.2 |
| Fear of movement (TSK, 17–68) | 36.5 ± 7.7 | 37.1 ± 8.0 | 37.4 ± 8.3 |
| Anxiety (PROMIS, T score) | 58.8 ± 8.7 | 58.1 ± 8.0 | 58.3 ± 7.8 |
| Depression (PROMIS, T score) | 58.1 ± 8.1 | 55.7 ± 8.5 | 56.6 ± 8.1 |
| Function (6MWT, feet walked) | 1,386 ± 323 | 1,358 ± 305 | 1,316 ± 318 |
| Function (5TSTS, sit‐to‐stand times in 10 seconds) | 4.1 ± 1.5 | 4.0 ± 1.4 | 3.9 ± 1.5 |
| Physical activity, median (range) minutes per day of moderate‐to‐vigorous activity | 17.7 (7.4–29.0) | 16.5 (6.3–29.1) | 15.0 (7.3–36.0) |
| Physical activity, IPAQ SF, median (range) METs per week | 1,290 (504–3,276) | 1,108 (198–2,839) | 1,386 (297–2,970) |
| TENS use (n = 94) | |||
| Intensity used on lumbar locations, mA | 38.67 ± 7.98 | – | – |
| Intensity used on cervical locations, mA | 38.70 ± 7.24 | – | – |
| Minutes used per day, median (range) | 77.1 (51.4–109.7) | – | – |
Except where indicated otherwise, values are the mean ± SD. TENS = transcutaneous electrical nerve stimulation; 6MWT = 6‐minute walk test; 5TSTS = 5‐time sit‐to‐stand test; NRS = numerical rating scale; FIQ = Fibromyalgia Impact Questionnaire; SF‐36 = short‐form 36; PCS = Pain Catastrophizing Scale; PSEQ = Pain Self‐Efficacy Questionnaire; TSK = Tampa Scale of Kinesiophobia; PROMIS = Patient‐Reported Outcomes Measurement Information System; IPAQ SF = International Physical Activity Questionnaire short‐form; METs = metabolic equivalents.
Percentages are based on the number of participants who chose to respond.
P = 0.010 versus placebo TENS and no TENS groups.
Groups were stratified for opioid use during randomization.
P = 0.020.
P = 0.049.