Thirty-three participants were interviewed (Table 1). The sample was equally split across male (n = 17, 52%) and female (n = 16, 48%) participants, with a mean age of 45 years old. Most participants were educated to high school diploma or equivalent (n = 14, 42%), college/associate’s degree (n = 7, 21%) or Bachelor’s degree (n = 7, 21%). Geographical diversity within the US was also achieved across the South (n = 8, 24%), Midwest (n = 12, 36%), and West (n = 13, 39%)
The mean weight of the sample was 109 kgs (range: 74–170 kgs). The mean BMI was 37.6 kg/m2 (range: 27.4–56.6 kg/m2). Of those participants who had weight-related comorbidities, fifteen reported only one (n = 15/24, 63%) weight-related comorbidity. Comorbid conditions included T2DM (n = 12/24, 50%), hypertension (n = 11/24, 46%) and obstructive sleep apnea (n = 6/24, 25%). The majority of the sample (n = 29/33, 88%) were treatment naïve to weight-loss medications and surgery. Based on clinical characteristics, participants were classified into one of the following subgroups:
-
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
-
Individuals with obesity (BMI ≥ 30 kg/m2) without diabetes AND with one or more weight-related comorbidities (including: hypertension, dyslipidemia, obstructive sleep apnea or cardiovascular disease)
-
Individuals with obesity (BMI ≥ 30 kg/m2) without diabetes or any other weight-related comorbidities.
-
Concept elicitation findings
Table 1
Participant clinical characteristics and demographics
Clinical and demographic characteristics
|
Total
(N = 33)
n (%)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
(N = 12)
n (%)
|
Individuals with obesity (BMI ≥ 30 kg/m2) without diabetes, AND with ≥ 1 weight-related comorbidity
(N = 12)
n (%)
|
Individuals with obesity (BMI ≥ 30 kg/m2) without diabetes or weight-related comorbidities
(N = 9)
n (%)
|
Current weight (kg)
Mean (Median) [Range]
|
109.2 (104.3)
[73.9-170.1]
|
102.5 (102.1)
[73.9-148.8]
|
111 (108.7)
[88-140.2]
|
114.1 (104.3)
[84.4-170.1]
|
Current BMI (kg/m2)
Mean [Range]
|
37.6
[27.4–56.6]
|
35.5
[27.4–49.9]
|
39.0
[30.0-56.6]
|
38.4
[30.0-50.9]
|
Comorbidities*
Type 2 diabetes
Hypertension
Obstructive sleep apnea
Dyslipidemia
Cardiovascular disease
|
12 (36%)
11 (33%)
6 (18%)
3 (9%)
3 (9%)
|
12 (100%)
3 (25%)
1 (8%)
1 (8%)
2 (17%)
|
N/A±
8 (67%)
5 (42%)
2 (17%)
1 (8%)
|
N/A±
N/A
N/A
N/A
N/A
|
Weight-loss treatment history
Currently on treatment
Previously received treatment
Treatment naive
|
1 (3%)
3 (9%)
29 (88%)
|
0
0
12 (100%)
|
1 (8%)
1 (8%)
10 (83%)
|
0
2 (22%)
7 (78%)
|
Sex
Male
Female
|
17 (52%)
16 (48%)
|
8 (67%)
4 (33%)
|
6 (50%)
6 (50%)
|
3 (33%)
6 (67%)
|
Age, years
Mean (Median) [Range]
|
45 (43)
[19–81]
|
51 (49)
[36–81]
|
42 (40)
[19–75]
|
43 (44)
[24–56]
|
Highest level of education
High school, but no diploma
High school diploma or equivalent
College or associate’s degree
Bachelor’s degree
Some graduate/post-graduate work
Graduate/post-graduate degree
Other (Vocational qualification)
|
3 (9%)
14 (42%)
7 (21%)
7 (21%)
1 (3%)
0
1 (3%)
|
2 (17%)
4 (33%)
4 (33%)
2 (17%)
0
0
0
|
1 (8%)
5 (42%)
3 (25%)
2 (17%)
1 (8%)
0
0
|
0
5 (56%)
0
3 (33%)
0
0
1 (11%)
|
Weight was reported by participants in pounds, but has been converted into kg |
* Clinicians may have selected multiple responses for each participant; ± Not applicable due to the sub-group eligibility criteria (e.g., Obesity without diabetes or weight-related comorbidities) |
Participants were familiarized with the concept of minimally important weight-loss and discussing the amount of body weight they would expect to lose to have a noticeable improvement on their physical functioning in the concept elicitation portion of the interview.
How participants assess weight-loss
When asked to discuss weight-loss in their own words, most participants described measuring and thinking of weight-loss using a combination of terms including pounds (n = 28), clothing size (n = 16), inches (n = 2) and BMI (n = 2).
-
I: So, first of all, in what units or terms do you typically talk about weight or measuring your weight? “The weight itself? I guess it would be in pounds.” (Male, 36, BMI: 34.7 kg/m2)
-
“I always think of it in terms of clothing sizes or pounds.” (Female, 44, BMI: 47.3 kg/m 2 )
One participant in the sample described how they did not measure their weight-loss numerically, but based it on changes in physical appearance. Another participant described thinking of improvement in their ability to do physical activities when measuring weight-loss.
Units used to discuss weight-loss
The majority of participants spoke in pounds (n = 22), but a number of participants (n = 7) were able to offer answers in percentages. Two participants had difficulty with percentages and a further two participants did not answer. This suggested that participants were not familiar with independently thinking of weight-loss in terms of percentage. They found it challenging to visualize a percentage loss of their total body weight and the implications this would have on their ability to perform physical activities.
Participant interpretations of percentage weight-loss
As some participants appeared to have difficulty understanding the concept of a percentage weight-loss, interviewers provided the number of pounds the percentage weight-loss would equate to for that individual’s weight. Participants spoke both in terms of improvement in their ability to perform physical activities and physical appearance and when asked, were able to explain what difference the weight-loss would make in their daily activities (Table 2).
Additionally, when discussing the smallest percentage change in body weight that would be noticeable and considered meaningful, fourteen participants spontaneously spoke about increased energy levels before thinking of how this would impact their physical functioning and specific daily activities.
5% total body weight-loss:
Over two-thirds of participants (23/33, 70%) felt that a 5% weight-loss would be noticeable. When discussing the difference a 5% weight-loss would make, participants mentioned they would expect increased energy (n = 7)/stamina (n = 2), to be more active (n = 3) and feel ‘lighter on their feet’ (n = 1). When speaking of physical functioning, participants expected a noticeable difference/improvement in their ability to stand (n = 2), walk distances (n = 2), and bend (n = 1) and expected increased mobility (n = 1). Additionally, participants expected a 5% weight-loss to reduce the pain experienced while completing daily activities (n = 3) and improve breathing (n = 2). Ten participants (10/33, 30%) did not feel 5% weight-loss would be significant enough to make a difference to performing daily activities.
10% total body weight-loss:
All participants (33/33, 100%) reported that a 10% weight-loss would be noticeable. When discussing 10% weight-loss, participants mentioned they would expect increased energy (n = 15)/stamina (n = 1), to be more agile/mobile (n = 5), with two participants specifically expecting to be able to move faster in addition to generally being more physically active (n = 4). Participants also discussed that a 10% weight-loss would improve their ability to walk, either for longer distances or at a quicker pace (n = 5), hike (n = 2), run (n = 1) and complete household chores (n = 2). One participant, who had previously used a walker, also mentioned they would expect to be able to move without assistance. Similar to a 5% weight-loss, participants expected a reduction in the pain experienced whilst completing daily activities (n = 3) and improved breathing (n = 2).
15% total body weight-loss:
All participants (33/33, 100%) reported that a 15% weight-loss would be noticeable. Participants discussed expecting improvements in climbing the stairs (n = 2), exercising (n = 2) and a noticeable improvement in ability to bend (n = 1) and when discussing a 15% weight-loss. One participant also reported they would expect to be able to care for themselves and not need to rely on others for assistance when moving around. Compared to a 5% or 10% weight-loss, twice as many participants expected a reduction in the pain experienced while completing daily activities (n = 6) with a 15% weight-loss and the same number expected improved breathing (n = 2).
Table 2
Participant perceptions of meaningful weight-loss
% weight-loss
|
Noticeable?
(N = 33)
|
Participant quotes
|
Y
|
N
|
5%
|
n = 23 (70%)
|
n = 10 (30%)
|
− Yes, noticeable:
− “I think that with some activities that I might want to do, I might be able to walk to the end of the block. I think that that would give me back some of my mobility.” (Female, 44, BMI: 47.3 kg/m2)
− “… Being able to bend over and do stuff a little bit better.” (Male, 32, BMI: 50.9 kg/m2)
|
− No, not noticeable:
− “No, I don’t think so. It would be nice, but I don’t think it’s noticeable or would make a difference.” (Male, 43, BMI: 40.2 kg/m)
− “I don’t think that’s enough for me to lose really to be noticeable.” (Male, 61, 34.2 kg/m)
|
10%
|
n = 33 (100%)
|
n = 0
(0%)
|
− Yes, noticeable:
− “It would make a big difference. I think like I said, I would be more agile. I would have more energy to do things. I wouldn’t feel as tired. More energy I think.”(Female, 50, BMI: 35.2 kg/m2)
− “And also, the activities you do. I mean, you’re more – you want to do them. Like before, you fretted doing cutting the grass; now you look forward to cutting the grass.” (Male, 53, BMI: 42.8 kg/m2)
− “I could probably wear some of the clothes that I have hiding in my closet that I haven't worn in a while […] And then definitely my energy level would be that much higher, you know […] I can probably do more planking and more activities at the gym.” (Female, 39, BMI: 40.0 kg/m)
|
15%
|
n = 33 (100%)
|
n = 0
(0%)
|
− Yes, noticeable:
− “Oh, just like I said before, the more weight I lose, the more flexibility I have and the less pain on the knees and on the back.” (Male, 54, BMI: 27.5 kg/m2)
− “Yeah. I would be able to go up some stairs without losing breath. I wouldn't stop halfway up the stairs. I only have 15 stairs. My daughter’s at the top and I'm in the middle. I'm catching my breath. It would just be a really big change. I would be able to do things that I can't now.”(Female, 20, BMI: 33.9 kg/m2)
− “I'd probably be able to walk. I'd probably be able to bend, throw, do whatever.” (Female, 45, BMI: 39.9 kg/m2)
− “Probably be able to go out hiking and do more things, like to go amusement park and ride a rollercoasters, because those rollercoasters are not big people friendly.” (Male, 32, BMI: 50.9 kg/m2)
|
For a 5% body weight-loss, individuals ‘without T2DM but with at least one other weight-related comorbidity’ were more likely to consider the change noticeable (n = 10/12, 83%) than those ‘with T2DM’ (n = 8/12, 67%) or those ‘without T2DM or any other weight-related comorbidities’ (n = 5/8, 62.5%; Fig. 3). |
Cognitive debriefing findings: SF-36v2 (acute)®
Thirty-one participants were asked to complete the meaningful change task thinking about Item 3f (Bending, kneeling or stooping) of the SF-36v2 (acute) following the principles of the Scaffold Approach. Participants were asked to imagine they had selected ‘Yes, limited a lot’.
A 1-point change at the item-level was considered the smallest meaningful improvement by the majority of participants (n = 28). A 1-point change at the item-level was also considered a meaningful improvement for most participants when considering how their ability to bend, kneel or stoop would change with a 5% (n = 18) or 10% (n = 16) total body weight-loss. However, participants expected a larger point change of 2-points with a 15% total body weight-loss (n = 21) (Table 3). A 1-point change at the item-level was considered indicative of meaningful worsening for the majority of participants.
The findings were broadly consistent across the three overweight/obesity sub-groups (Table 4). When considering a 10% and a 15% weight-loss, the mean point score considered a meaningful change was higher for individuals ‘without T2DM but at least one other weight-related comorbidity’ (10% mean: 1.7; 15% mean: 1.7) than those ‘with T2DM’ (10% mean: 0.9; 15% mean: 1.5) and those ‘without T2DM or any other weight-related comorbidities’ (10% mean: 1.0; 15% mean: 1.6).
Cognitive debriefing findings: IWQOL-Lite-CT©
Frequency response scale
Thirty-one participants were asked to complete the meaningful change task thinking about Item 2 (Tired or winded walking up one flight of stairs) of the IWQOL-Lite-CT, which utilized a frequency scale. Participants were asked to imagine they had selected ‘sometimes’.
A 1-point change at the item-level was considered the smallest meaningful improvement by the majority of participants (n = 29). A 1-point change at the item-level was also considered a meaningful improvement for most participants when considering how their ability to walk up one flight of stairs without feeling tired or winded would change with a 5% (n = 19) or 10% (n = 16) total body weight-loss. However, participants expected a larger point change of 2-points with a 15% weight-loss (n = 20) (Table 3). A 1-point change at the item-level was considered indicative of meaningful worsening by the majority of participants.
The findings were broadly consistent across the three overweight/obesity sub-groups (Table 4). When considering a 10% and a 15% weight-loss, the mean point scores were higher for individuals ‘without T2DM but at least one other weight-related comorbidity’ (10% mean: 1.5; 15% mean: 1.9) than those ‘with T2DM’ (10% mean: 1.1; 15% mean: 1.5) and those ‘without T2DM or any other weight-related comorbidities’ (10% mean: 1.0; 15% mean: 1.3).
‘Truth’ response scale
Thirty-one participants were asked to complete the meaningful change task thinking about Item 16 (Not as physically active as I would like to be) of the IWQOL-Lite-CT, which utilized a truth scale. Participants were asked to imagine they had selected ‘moderately true’.
A 1-point change at the item-level was considered the smallest meaningful improvement by the majority of participants (n = 27). A 1-point change at the item-level was also considered a meaningful improvement for most participants when considering how their ability to be physically active would change with a 5% (n = 18) or 10% (n = 17) total body weight-loss. However, participants expected a larger point change of 2-points with a 15% weight-loss (n = 19) (Table 3). A 1-point change at the item-level was considered indicative of meaningful worsening for the majority of participants.
The findings were broadly consistent across the three overweight/obesity sub-groups (Table 4). When considering a 5%, 10% and a 15% weight-loss, the mean point scores were higher for individuals ‘without T2DM but at least one other weight-related comorbidity’ (5% mean: 0.9, 10% mean: 1.5; 15% mean: 2.0) than those ‘with T2DM’ (5% mean: 0.4, 10% mean: 1.0; 15% mean: 1.4) and those ‘without T2DM or any other weight-related comorbidities’ (5% mean: 0.4, 10% mean: 1.0; 15% mean: 1.5).
Table 3
Perceptions of meaningful change on the SF-36v2 (acute) and the IWQOL-Lite-CT
SF-36v2 (acute) - Item 3f - bending, kneeling or stooping (Severity scale)
|
Change from baseline ‘Yes, limited a lot’
|
Point change considered meaningful
|
Mean†
|
0
Yes, limited a lot
|
+ 1
Yes, limited a little
|
+ 2
No, not limited at all
|
Smallest meaningful improvement (n = 31)
|
0
|
28
|
3
|
1.1
|
5% weight-loss (n = 31)
|
11
|
18
|
2
|
0.7
|
10% weight-loss (n = 31)
|
4
|
16
|
11
|
1.2
|
15% weight-loss (n = 31)
|
3
|
7
|
21
|
1.6
|
Change from baseline ‘No, not limited at all’
|
Point change considered meaningful
|
Mean†
|
0
No, not limited at all
|
-1
Yes, limited a little
|
-2
Yes, limited a lot
|
Smallest meaningful worsening (n = 29)
|
0
|
19
|
10
|
1.3
|
IWQOL-Lite-CT Item 2 – Tired or winded walking up one flight of stairs (Frequency scale)
|
Change from baseline ‘Sometimes’
|
Point change considered meaningful
|
Mean†
|
0
Sometimes
|
-1
Rarely
|
-2
Never
|
Smallest meaningful improvement (n = 31)
|
0
|
29
|
2
|
1.1
|
5% weight-loss (n = 31)
|
11
|
19
|
1
|
0.7
|
10% weight-loss (n = 31)
|
4
|
16
|
11
|
1.2
|
15% weight-loss (n = 31)
|
2
|
9
|
20
|
1.6
|
Change from baseline ‘Sometimes’
|
Point change considered meaningful
|
Mean†
|
0
Sometimes
|
+ 1
Usually
|
+ 2
Always
|
Smallest meaningful worsening (n = 30)
|
0
|
26
|
4
|
1.1
|
IWQOL-Lite-CT - Item 16 – Not as physically active as I would like to be (Truth scale)
|
Change from baseline ‘Moderately true’
|
Point change considered meaningful
|
Mean†
|
0
Moderately true
|
-1
A little true
|
-2
Not at all true
|
Smallest meaningful improvement (n = 29)
|
0
|
27
|
2
|
1.1
|
5% weight-loss (n = 30)
|
12
|
18
|
0
|
0.6
|
10% weight-loss (n = 31)
|
4
|
17
|
10
|
1.2
|
15% weight-loss (n = 30)
|
0
|
11
|
19
|
1.6
|
Change from baseline ‘Moderately true’
|
Point change considered meaningful
|
Mean†
|
0
Moderately true
|
+ 1
Mostly true
|
+ 2
Completely true
|
Smallest meaningful worsening (n = 29)
|
0
|
20
|
9
|
1.3
|
† Mean rounded to one decimal place. Shaded cells indicate the most frequently selected point change. |
Table 4
Perceptions of meaningful change on the SF-36v2 (acute) the IWQOL-Lite-CT among overweight/obesity subgroups
SF-36v2 (acute) - Item 3f - bending, kneeling or stooping (Severity scale)
|
Change from baseline ‘Yes, limited a lot’
|
Mean point change considered meaningful †
|
Smallest meaningful improvement (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.0
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.2
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.1
|
5% weight-loss (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
0.6
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
0.9
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
0.6
|
10% weight-loss (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
0.9
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.7
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.0
|
15% weight-loss (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.5
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.7
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.6
|
Change from baseline ‘No, not limited at all’
|
Mean point change considered meaningful †
|
Smallest meaningful worsening (n = 29)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.2
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.4
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.4
|
IWQOL-Lite-CT Item 2 – Tired or winded walking up one flight of stairs (Frequency scale)
|
Change from baseline ‘Sometimes’
|
Mean point change considered meaningful †
|
Smallest meaningful improvement (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.0
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.1
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM/or any other comorbidities
|
1.1
|
5% weight-loss (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
0.5
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
0.9
|
Individuals with obesity (BMI ≥ 30 kg/m2) without / T2DM/or any other comorbidities
|
0.7
|
10% weight-loss (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.1
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.5
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM/or any other comorbidities
|
1.0
|
15% weight-loss (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.5
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.9
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.3
|
Change from baseline ‘No, not limited at all’
|
Mean point change considered meaningful †
|
Smallest meaningful worsening (n = 30)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.1
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.1
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.2
|
IWQOL-Lite-CT - Item 16 – Not as physically active as I would like to be (Truth scale)
|
|
Change from baseline ‘Moderately true’
|
Mean point change considered meaningful †
|
Smallest meaningful improvement (n = 29)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.0
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.2
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.0
|
5% weight-loss (n = 30)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
0.4
|
Individuals with obesity (BMI ≥ 30kg/m2) without T2DM but with other comorbidities
|
0.9
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
0.4
|
10% weight-loss (n = 31)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.0
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.5
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.0
|
15% weight-loss (n = 30)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.4
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
2.0
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.5
|
Change from baseline ‘Moderately true’
|
Mean point change considered meaningful †
|
Smallest meaningful worsening (n = 29)
|
Individuals with overweight or obesity (BMI ≥ 27 kg/m2) with T2DM
|
1.2
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM but with other comorbidities
|
1.4
|
Individuals with obesity (BMI ≥ 30 kg/m2) without T2DM or any other comorbidities
|
1.3
|
† Mean rounded to one decimal place. |