High Level Pulsed Heat Versus Low Level Steady Heat in Subjects With Chronic Low Back Pain
Phase: NA
Conditions: Chronic Pain, Low Back Pain, Heat, Analgesia
Sponsor: Soovu Labs Inc.

 
 
ID: 201969K 
    High Level Pulsed Heat Versus Low Level Steady Heat in Subjects With Chronic Low Back Pain 
December 3, 2019 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
Carewave Series 5 Clinical Trial:  A randomized double blinded two arm study comparing 
pain relief in an active Series 5 device group (113 °F) versus a Series 5 lower 
temperature group (96.8 °F) in subjects with chronic low back pain. 
 
 
Study Overview 
1. This study will be conducted under Good Clinical Practice (GCP) guidelines and suitable for FDA submission in order to obtain 
claims such as, “provides temporary pain relief for people with chronic lower back pain.” 
2. The study is designed as a randomized double blinded two arm placebo controlled trial.  
3. The active arm (N=50) receives two active Series 5 heating units (Soovu Labs Inc.) that pulse heat to 45°C (113°F). The active 
Series 5 placebo arm (N=50) gets two identical appearing units (Soovu Labs Inc.) that produce low level of heat at 35-36°C 
(96.8 °F). For reference skin temperature is about 33 °C and room temperature 23 °C. 
4. The study hypothesis is that in subjects with chronic low back pain, the active high level pulses heating device group will 
show a statistical improvement in pain scores as compared to the low level steady heat group as measured by the primary 
outcome measure, the Numeric Pain Scale (NPS). 
5. Subjects will be told the study is examining the pain relieving effectiveness of two different levels of heat.  
6. Subjects must have chronic low back pain with a pretreatment level of pain 4 or greater on a 0-10 point scale. By definition 
chronic low back pain is a condition that has been present for at least 6 months and must be present more days than not 
over the course of a week. 
7. No use of pain medications during the four hour trial. However, pain medications including schedule IIIs can be taken up to 
30 minutes before the start of the trial. Medications permitted during the trial include medications such as tramadol, 
codeine, NSIADs, gabapentin and acetaminophen. Non-pain medications for medical indications are permitted at any time. 
Subjects taking schedule II opioids are excluded from the study. Schedule II opioids include oxycodone, hydromorphone, 
hydrocodone, fentanyl and methadone. 
8. Ages 22 through 70. 

9. Exclusion criteria- sciatica if present must be rated significantly less than the non -radiating component of the low back pain,  
pregnancy, skin lesions such as open skin or sores, scar tissue, skins grafts, old burns over the treatment area or neuropathic 
sensory loss over the treatment site. 
10. Pre-treatment assessments include, Numeric Pain Scale (static and bending), and a pre-study questionnaire (history, 
treatment preferences, short form Brief Pain Inventory, and short form Magill), and a timed walking test.  
11. Each treatment session lasts approximately 30 minutes with pain assessments throughout using NPS (primary outcome 
measure). Secondary outcome measures include measures of comfort, willingness to endorse their treatment and a timed 
walking test including the number of strides. 
12. All subjects are followed for a 4 hour post treatment period with intermittent pain assessments (NPS). 
13. At the end of the post treatment period, subjects complete a post study usability questionnaire and a blinding questionnaire. 
 
 
Study arm #1- Active treatment group (two heating units) 
1. Subjects randomized to this group will receive two active Series 5 heating units. The active heating units produce waves of 
heat of up to 45°C. All subjects will start at 45°C (113° F). 
2. The treatment session is approximately 30 minutes of active treatment with heat.  
3. Pain is assessed using a standardized instrument (the numerical pain score) both static and with bending/flexion. 
4. Assessment times include pretreatment (T-0) after 5 minutes of treatment (T-5), after 10 minutes of treatment (T-10), after 
15 minutes of treatment (T-15), and after 30 minutes of treatment (T-30).  
5. Pain is also assessed after treatment ends. This assessment is done at 15, 30, 45, and 60 minutes post-treatment. After 60 
minutes into the post-treatment, pain is assessed every 30 minutes up to 4 hours post-treatment. 
6. Number of subjects in active treatment arm - up to 50.  
 
 
Study arm #2- Low level heat treatment group (two low level heat units) 
1. Subjects randomized to this group will receive two placebo Series 5 heating units. These devices look exactly like the active 
heating units but produce low level heat at 35-36°C (96.8 °F). 
2. The treatment session is approximately 30 minutes of active placebo treatment.  
3. Pain is assessed using a standardized instrument (the numerical pain score) both static and with bending/flexion. 
4. Assessment times include pretreatment (T-0) after 5 minutes of treatment (T-5), after 10 minutes of treatment (T-10), after 
15 minutes of treatment (T-15), and after 30 minutes of treatment (T-30).  

5. Pain is also assessed after treatment ends. This assessment is done at 15, 30, 45, and 60 minutes post-treatment. After 60 
minutes into the post-treatment time, pain is assessed every 30 minutes up to 4 hours post-treatment. 
6. Number of subjects in placebo arm - up to 50. 
 
 
 
Inclusion criteria 
1. Chronic low back pain. By definition chronic low back pain is a  condition that has been present for at least 6 months on more 
days than not. If there is a radiating component of the low back pain the radiating component must have a pain rating less 
than the non-radiating component of the low back pain. 
2. Subjects must have pretreatment level of pain 4 or greater.  
3. Ages 22 through 70 
4. Pain medications can be used prior to the trial; however, none can be used during the approximate four hour trial. Other 
non-pain medications are permitted as needed.  
5. Medications permitted during the trial include medications such as tramadol, codeine, NSIADs, gabapentin and 
acetaminophen.  
 
Exclusion criteria 
1. Sciatica or radicular pain without non-radiating low back pain, cancer, radicular pain greater than the non-radiating 
component of low back pain, pregnancy, skin lesions such as open skin or sores, scar tissue, skins grafts, old burns over the 
treatment area 
2. Subjects must have a cell phone for clinic contact and follow-up. 
3. Medications including oxycodone, hydromorphone, hydrocodone, fentanyl and methadone are excluded from the trial. 
 
 

 
Primary measure: pain using Numerical Pain Scale 
1. Numerical Pain Scale (see figure 1) at rest compared to the NPS after 30 minutes of treatment. 
 
Secondary measures 
 
1. Comfort scale and  willingness to recommend treatment assessments (see figure 2). These assessments are administered 
after the treatment session and at end of the post-treatment period. 
2. Numerical Pain Scale (see figure 1) with painful movement. Painful movement is defined as any movement that increases the 
amount of pain the subjects experience. This movement may include stretching, bending forward backward or sideways as 
well as any other movements identified by the subject. 
 
Other measures 
 
1. Speed walk. Time for an individual to walk a total distance of 60 feet. (Assessing walking speed in clinical research: a 
systematic review (J eval. Clinic Practice 2008 14(4) 552-562, or  www.physio-pedia.com/10metre_Walk_test) Walk 60 feet 
but time only the middle 20 feet. The number of strides over the middle 20 feet will also be recorded. 
2. Pain relief for up to 4 hours after treatment session ends using the Numeric Pain Scale 
3. Skin observation at baseline, at the end of active 30 minute treatment and at the end of 4 hours. The subject will be asked 
how the skin feels and observed for any redness. 
 
Study methods 
1. Prior to initiation subjects will complete a short pre-study questionnaire about their chronic back pain (see figure 3). The 
questionnaire asks subjects about the history of their back pain, pain rating, and past and present treatments. 
 
2. All subjects will be told that they are testing devices with two different temperatures and the effect of the different 
temperatures on low back pain. The words low temperature or higher temperature are not used. The low level 
temperature Series 5 device 35-36°C (96.8 °F) functions as an active placebo. All subjects will view a short presentation 
that explains the pain scale, double blinded trials and active versus placebo conditions to standardize the study approach. 
 

3. At initiation of each trial, subjects will be shown the device active or placebo. The devices look identical. Subjects will be 
asked to indicate the area of worst pain by pointing to the spot. This will be the starting position of the device. Once 
treatment starts the subject can adjust the location of the device to the most effective area. The starting temperature of 
the active device will be 36 °C in the low temperature series 5 device and 45°C in the higher temperature series 5 device. 
 
4.  Any location change will be recorded. Subjects can also change the temperature setting anytime during the study. The 
change will be made by the study assistant using the phone app. This will be also be recorded. Subjects in the placebo 
group can also ask to change the location or temperature with the same response by the study assistant. All requests will 
be recorded. Series 5 devices are controlled using one of two methods, tapping on the device can turn the device on or 
off, or via blue tooth connection on a cell phone app. For this study we will use the blue tooth interface because it is 
simpler than tapping the device especially if the subject wishes to change the temperature as the devices are placed on 
the low back possibly making it difficult for some subjects in pain to reach the device to properly tap it.  
 
The research assistant (RA) will have a dedicated cell phone that paired with the subject’s heating units and only those 
Series 5 devices. The RA can lower the temperature at the subject’s request. The cell phone app contains an on/off switch 
to the paired unit, a temperature monitor and the ability to lower the temperature of the unit. For this study the 
temperature cannot be increased over 113 or 96.8 °F in the study units ( Higher versus lower temperature series 5 units 
respectively). To support study blinding subjects will not have access to the cell phone app.  
 
5. Pain will be measured both at rest and with an activity that each subject identifies as causing pain such as bending 
forward, backward or laterally or stretching. 
 
6. Subjects will be required to stay for the full 4 hours post-treatment period even if their pain returns to baseline. 
 
7. At the end of the post-treatment period subjects will complete a blinding questionnaire (see figure 4) and treatment 
usability questionnaire (see figure 5). The blinding questionnaire will also be administered at the end of the post-
treatment period. 
 
8. The study timeline and assessment schedule are shown on figure 7. 
 
 

Data analysis of primary outcome measure 
 
Primary analysis will consist of a two-sample t-test comparing change in numeric pain score (0 – 10 point scale) from baseline to 5, 
10, 15, and 30 minute time point between the active and control arms using participants with complete observations. We will also 
analyses the pain level data at regular endpoints up to 4 hours post treatment. Residual change scores will be tested for departure 
from normality using the Shapiro-Wilk test for normality. If a statistically significant department from normality is observed, we will 
use the Mann-Whitney-Wilcoxon test instead of a two-sample t-test. Secondary analysis will use two-sample t-tests to compare 
comfort with device (measured on a 0-10 scale) between arms and willingness to endorse treatment for others (measured on a 0-10 
scale) between arms and pain with movement. Statistical tests will be conducted at the alpha = 0.05 level. 
 
 
 

Figure 1:  Primary outcome measure (NPS) Static 
 
 
Primary outcome measure is the Numeric Pain Scale (NPS) - Validity of four pain intensity rating scales.  Pain 2011, 
Oct;152(10):2399-404. doi: 10.1016/j.pain.2011.07.005. 
 
 
 

Figure 1A:  Primary outcome measure (NPS) Dynamic (flexion or extension) 
 
 
Primary outcome measure is the Numeric Pain Scale (NPS) - Validity of four pain intensity rating scales.  Pain 2011, 
Oct;152(10):2399-404. doi: 10.1016/j.pain.2011.07.005. 
 
 

 
Figure 2:  Subject satisfaction measures 
 
Please indicate the comfort level of your treatment by checking the appropriate box. 
 
 
 
 
 
 
 
Very 
uncomfortable 
Moderately 
uncomfortable 
Mildly 
uncomfortable 
Comfortable 
Mildly 
comfortable 
Moderately 
comfortable 
Very 
comfortable 
 
 
 
 
How likely would you recommend your treatment to others by checking the appropriate box? 
 
 
 
 
 
 
 
Very unlikely 
Moderately 
unlikely 
Mildly 
unlikely 
Likely 
Mildly likely 
Moderately 
likely 
Very likely 
Comfort and recommendation assessments. 
 
 

 
Figure 3:  Pre-study questionnaire 
 
About how long have you had back pain? (months or years) 
 
 
 
 
 
Please circle where your pain is located 
If there is a radicular component, please indicate pain level of radicular and of non-radiating low back pain. 
 

 
 
 
1. How motivated are you to do something about your chronic pain? 
1. Not at All (exclude from study) 
2. Slightly (exclude) 
3. Somewhat 
4. Very much 
5. Extremely 
  
2. What have you done in the past to treat your chronic pain? How effective was each? 
 
 
 
 
 
  
3. Gender: 
1. Male 
2. Female 
  
4.       What is your age?  
1. 22-30 
2. 31-40 
3. 41-50 
4. 51-60 
5. 61-70 
6. 71+  
  
 
 
  
6.       What is your current employment status? 

1.       Employed full-time 
2.       Employed part-time 
3.       Self-employed 
4.       Full-time student 
5.       Homemaker 
6.       Retired 
7.       Unemployed 
8.       Prefer not to answer 
  
7.       What is the highest level of education you have achieved? 
1. Some high school 
2. High school graduate 
3. Some college 
4. Associates degree or technical degree 
5. College degree 
6. Graduate coursework or degree 
7. Prefer not to answer 
  
8.       Overview of your household 
1.       Married 
2.       Single 
3.       Living with partner 
4.       Children in household 
  
9.       How many days a week do you typically exercise? 

1.       None 
2.       1-2 
3.       3-5 
4.       Every day 
 
 
 
 
What treatments or medications have you tried for your low back pain? Please check the box. 
 
Past treatments 
Did not use Used but 
little help 
Used and helped 
somewhat 
Used with great 
help 
Anti-inflammatory medications like ibuprofen, 
naproxen 
 
 
 
 
Opioids, narcotics 
 
 
 
 
Surgery 
 
 
 
 
Physical therapy 
 
 
 
 
Massage 
 
 
 
 
Chiropractic care 
 
 
 
 
Magnetic energy devices 
 
 
 
 
Heat 
 
 
 
 
Ice 
 
 
 
 
Transcutaneous Electrical nerve Stimulation (TENS) 
 
 
 
 
 
 
 
 

 
Activity 
Never or rarely 
1-2 days per week 3-5 days per week 
Ø 5 days per week 
Walk 
 
 
 
 
Exercise other than walking 
 
 
 
 
Use a computer 
 
 
 
 
Use a smart phone 
 
 
 
 
 
 
 
 
 
Please circle the number that describes how, during the past 24 hours, pain has interfered with your: 
 
A. General activity 
 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
No interference 
 
 
 
 
 
 
 
Completely 
interferes 
 
 
 
 
 
 
 
 
 
 
B.  Mood 
 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
No interference 
 
 
 
 
 
 
 
Completely interferes 
 
 
 
 
 
 
 
 
 
 
C. Walking ability 
 
 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
No interference 
 
 
 
 
 
 
 
Completely interferes 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

D. Normal Work (includes both work outside the home and housework) 
 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
No interference 
 
 
 
 
 
 
 
Completely interferes 
 
 
E. Relations with other people 
 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
No interference 
 
 
 
 
 
 
 
Completely interferes 
 
 
 
 
 
 
 
 
 
 
F. Sleep 
 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
No interference 
 
 
 
 
 
 
 
Completely interferes 
 
 
 
 
 
 
 
 
 
 
G. Enjoyment of life 
 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
No interference 
 
 
 
 
 
 
 
Completely interferes 
 
(from BPI short form, C. Cleland) 
 
 
 
 
 

 
 
 
Please circle the words that describe your pain: 
 
Throbbing 
Shooting 
Stabbing 
Sharp 
Cramping 
Gnawing 
Hot 
Burning 
Aching 
Heavy 
Tender 
Splitting 
Tiring 
Exhausting 
Sickening 
Fearful 
Cruel 
 
 
 
 
 (From the short-form McGill Pain Questionnaire, R. Melzack 1984) 
 
 
 
 
 

Figure 4:  Blinding questionnaire 
 
Subject: 
 
 
Please place a checkmark next to the item that best indicates your opinion. Only one 
checkmark please. 
                                                                                                                                ß 
I strongly believe that I received the low heat device during this study. 
 
 
I somewhat believe that I received the low heat device during this study. 
 
 
I am not sure whether I received the low heat or the higher heat device 
during this study. 
 
 
I somewhat believe that I received the higher heat device during this 
study. 
 
 
I strongly believe that I received the  higher heat device during this study. 
 
 

Figure 5:  Post study usability questionnaire 
 
 
Please indicate the extent to which you agree or disagree with each of the following statements: 
  
 
Strongly 
Disagree 
Disagree 
Neither Agree 
or Disagree 
Agree 
Strongly 
Agree 
I prefer to use this product over a traditional heating 
pad 
 
 
 
 
 
 
 
 
Strongly 
Disagree 
Disagree 
Neither Agree 
nor Disagree 
Agree 
Strongly 
Agree 
I prefer to use this product over any other pain relief 
therapy I’ve tried 
 
 
 
 
 
 
 
 
Strongly 
Disagree 
Disagree 
Neither Agree 
nor Disagree 
Agree 
Strongly 
Agree 
By regularly using this product, I feel I could reduce 
my stress 
 
 
 
 
 
 
 
Strongly 
Disagree 
Disagree  
Neither Agree 
nor Disagree 
Agree 
Strongly 
Agree 
By regularly using this product, I feel I could better 
engage in life 
 
 
 
 
 
 
 
 
Strongly 
Disagree 
Disagree 
Neither Agree 
nor Disagree 
Agree 
Strongly 
Agree 
I found the product to be comfortable and soothing 
 
 
 
 
 
 
 
 
Strongly 
Disagree 
Disagree 
Neither Agree 
nor Disagree 
Agree 
Strongly 
Agree 
I would like to continue use of the product at home 
 
 
 
 
 

 
 
 
 
Strongly 
Disagree 
Disagree 
Neither Agree 
nor Disagree 
Agree 
Strongly 
Agree 
By regularly using this product, 
I feel I could be more productive at work 
 
 
 
 
 
 
 
 
Strongly 
Disagree 
Disagree 
Neither Agree 
nor Disagree 
Agree 
Strongly 
Agree 
By regularly using this product, I feel my 
relationships could be better 
 
 
 
 
 
  
 
 
 
 
On a scale of zero to 10, how likely is it that you would recommend the product to a friend, family member, or colleague? 
(0=not likely, 10=very likely)                                                                                                       
  
We may extend this study to using this product at home for several months. Are you interested in being informed about 
participating in this study? 
  
___ Yes      ___ No 
  
Are you open to having the manufacturer of the device contact you to conduct a short market research survey (for which you’d be 
compensated)? 
  
___ Yes      ___ No 
  
Best email to reach you at: _____________________________ 
 

Figure 6: Skin assessment form 
 
 
 
Subject number               date 
 
Time of assessment T-0.   T30.    T240 
 
 
How does the skin look? 
 
1- No change 
2- Changes in pigmentation, skin hue or tone? If so, please describe in detail. 
3- Evidence of changes in blood flow? For example, localized edema. If so, please describe in detail. 
 
 
 
Does the subject have pain at the site? Please note description of pain. Is there any stinging. How long has it been since the device 
was turned off? 
 
 
Other comments? 
 
 

 
Figure 7:  Study timeline and assessment schedule 
 
 
Active treatment 
Post-treatment period  
 
T-0 
T-5 
T-10 
T-15 
T-30 
PT-15 
PT-30 
PT-45 
PT-60 
PT-90 
PT-120 
PT-150 
PT-180 
PT-210 
PT-240 
Numeric pain scale at rest 
and movement 
x 
x 
x 
x 
x 
x 
x 
x 
x 
x 
x 
x 
x 
x 
x 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Subject satisfaction scales  
 
 
 
 
x 
 
 
 
x 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Orientation video 
x 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Speed walk test 
x 
 
 
 
x 
 
 
 
 
 
 
 
 
 
 
Pre-study questionnaire 
x 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Marketing questionnaire 
 
 
 
 
 
 
 
 
 
 
x 
 
 
 
 
Heat and food questionnaire 
 
 
 
 
 
 
 
 
 
 
 
 
x 
 
 
Blinding questionnaires 
 
 
 
 
 
 
x 
 
 
 
 
 
 
 
x 
Skin assessment 
x 
 
 
 
x 
 
 
 
 
 
 
 
 
 
x 
 
 Figure 7:  Outcome measures versus study timeline. 
 
 

Figure 8:  Temperature and food preferences 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
  
  
  
  
 
 
 
Strongly 
disagree 
Mildly 
disagree 
Mildly 
agree 
Strongly 
agree 
Other products I’ve tried that use heat to control pain have worked 
well for me. 
 
 
 
 
Other products I’ve tried that use cold to control pain have worked 
well for me. 
 
 
 
 
I like my coffee or tea hot 
 
 
 
 
I like my coffee or tea very hot 
 
 
 
 
I like cold drinks over hot drinks 
 
 
 
 
I tend to sweat easily 
 
 
 
 
I tend to overheat easily 
 
 
 
 
I tend to get cold easily 
 
 
 
 
I really like my shower or bath hot 
 
 
 
 
I really like my shower or bath very hot 
 
 
 
 
I have tried other pain relief products, and none worked for me. 
 
 
 
 
I like my food spicy 
 
 
 
 
I like my food very spicy