Introduction
Methods
Measures
Impact of Weight on Self-perception Questionnaire (IW-SP)
Ability to perform physical activities of daily living (APPADL)
Impact of weight on quality of life-lite clinical trials version (IWQOL-Lite-CT)
Analyses
Identifying potential anchors
Selection of anchors
Application of anchors to form groups
Group | Continuous anchors with existing MICsa | Individual itemsb |
---|---|---|
Group 1 | < 0.25 MIC (no change) | 0 category change (no change) |
Group 2 | 0.25 MIC to < 0.75 MIC improvement | + 1 category improvement* |
Group 3 | 0.75 MIC to < 1.25 MIC improvement* | + 2 category improvement |
Group 4 | 1.25 MIC to < 1.75 MIC improvement | + 3 category improvement |
Group 5 | 1.75 MIC to < 2.25 MIC improvement | + 4 category improvement |
Group 6 | 2.25 MIC to < 2.75 MIC improvement | |
Group 7 | > 2.75 MIC improvement |
Assessing meaningful change and responsiveness
Distribution-based approaches
Triangulation
Results
Sample description
Total (N = 1878) | MIC estimation (N = 1252) | MIC confirmation (N = 626) | |
---|---|---|---|
Sex, n (%) | |||
Male | 882 (47.0%) | 591 (47.2%) | 291 (46.5%) |
Female | 996 (53.0%) | 661 (52.8%) | 335 (53.5%) |
Ethnicity, n (%) | |||
Hispanic or Latino | 1317 (70.1%) | 869 (69.4%) | 448 (71.6%) |
Not Hispanic or Latino | 561 (29.9%) | 383 (30.6%) | 178 (28.4%) |
Race, n (%) | |||
American Indian or Alaska Native | 208 (11.1%) | 129 (10.3%) | 79 (12.6%) |
Asian | 25 (1.3%) | 16 (1.3%) | 9 (1.4%) |
Black or African American | 79 (4.2%) | 61 (4.9%) | 18 (2.9%) |
Native Hawaiian or other Pacific Islander | 3 (0.2%) | 1 (0.1%) | 2 (0.3%) |
White | 1551 (82.6%) | 1036 (82.7%) | 515 (82.3%) |
Multiple | 12 (0.6%) | 9 (0.7%) | 3 (0.5%) |
Age (years) | |||
n | 1878 | 1252 | 626 |
Mean | 56.6 | 56.5 | 56.7 |
SD | 10.4 | 10.5 | 10.3 |
Minimum | 21 | 21 | 24 |
Median | 57 | 57 | 57 |
Maximum | 91 | 82 | 91 |
Weight | |||
n | 1878 | 1252 | 626 |
Mean | 93.7 | 93.7 | 93.8 |
SD | 21.9 | 22.0 | 21.6 |
Minimum | 50 | 53 | 50 |
Median | 90 | 90 | 90 |
Maximum | 222 | 222 | 198 |
Baseline BMI | |||
N | 1878 | 1252 | 626 |
Mean | 34.2 | 34.1 | 34.5 |
SD | 6.9 | 6.8 | 7.1 |
Minimum | 23 | 24 | 23 |
Median | 33 | 33 | 33 |
Maximum | 89 | 89 | 86 |
Baseline A1C | |||
N | 1878 | 1252 | 626 |
Mean | 8.3 | 8.3 | 8.3 |
SD | 1.0 | 1.0 | 1.0 |
Minimum | 6 | 6 | 6 |
Median | 8 | 8 | 8 |
Maximum | 12 | 12 | 12 |
Score change | Stage | N | Mean change (SD) | Range (minimum–maximum) | Missing (%) | N, ρ b |
---|---|---|---|---|---|---|
IW-SP Score | Estimation | 1200 | 10.0 (26.3) | − 200 | 52 (4.2%) | – |
Confirmation | 603 | 11.7 (27.2) | − 200 | 23 (3.7%) | ||
IWQOL-Lite-CT Physical composite | Estimation | 1197 | 8.7 (18.9) | − 150 | 55 (4.4%) | 1799, 0.40**** |
Confirmation | 602 | 9.7 (20.2) | − 150 | 24 (3.8%) | ||
IWQOL-Lite-CT Physical Function composite | Estimation | 1197 | 9.5 (20.5) | − 150 | 55 (4.4%) | 1799, 0.40**** |
Confirmation | 602 | 10.6 (22.1) | − 160 | 24 (3.8%) | ||
IWQOL-Lite-CT Psychosocial composite | Estimation | 1197 | 8.2 (18.3) | − 167.3 | 55 (4.4%) | 1799, 0.57**** |
Confirmation | 602 | 9.8 (20.2) | − 134.6 | 24 (3.8%) | ||
IWQOL-Lite-CT Total Score | Estimation | 1196 | 8.4 (16.9) | − 155.1 | 56 (4.5%) | 1798, 0.56**** |
Confirmation | 602 | 9.8 (18.5) | − 127.5 | 24 (3.8%) | ||
APPADL Score | Estimation | 1199 | 5.8 (17.7) | − 128.5 | 53 (4.2%) | 1801, 0.35**** |
Confirmation | 602 | 6.3 (19.4) | − 150 | 24 (3.8%) | ||
IWQOL-Lite-CT Item 7 | Estimation | 1197 | − 0.3 (1.1) | − 8 | 55 (4.4%) | 1799, − 0.50**** |
Confirmation | 602 | − 0.4 (1.1) | − 8 | 24 (3.8%) | ||
IWQOL-Lite-CT Item 20 | Estimation | 1195 | − 0.3 (1.2) | − 8 | 57 (4.6%) | 1797, − 0.49**** |
Confirmation | 602 | − 0.5 (1.2) | − 7 | 24 (3.8%) | ||
Weight (KG, % Change) | Estimation | 1188 | − 9.0 (7.4) | − 53.7 | 64 (5.1%) | 1784, − 0.23**** |
Confirmation | 598 | − 9.9 (7.3) | − 42.1 | 28 (4.5%) |
Responsiveness and meaningful change analyses
Anchor selection and anchor-based analyses
Anchor | Mean type | < 0.25 MIC | 0.25 to < .0.75 MIC | 0.75 to < 1.25 MIC | 1.25 to < 1.75 MIC | 1.75 to < 2.25 MIC | 2.25 to < 2.75 MIC | > 2.75 MIC | Overall F-test b | Pairwise Comparison c | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
N | Mean | N | Mean | N | Mean | N | Mean | N | Mean | N | Mean | N | Mean | F | p-value | (p-value ) | ||
IWQOL-Lite-CT Physical composite MIC | Raw Mean (SD) | 113 | 5.7 (9.9) | 186 | 12.0 (17.1) | 152 | 16.8 (19.8) | 105 | 21.9 (21.7) | 75 | 26.2 (19.6) | 52 | 32.9 (23.3) | 90 | 37.4 (25.9) | 2**,3***,4***,5***,6***,8*,9*** ,10***,11***,14**,15***,18*** | ||
LS Mean (SE) | 113 | 6.9 (1.8) | 186 | 12.2 (1.4) | 152 | 16.9 (1.5) | 105 | 21.0 (1.9) | 75 | 25.7 (2.2) | 52 | 31.1 (2.7) | 90 | 35.6 (2.0) | 27.49 | < .0001 | ||
IWQOL-Lite-CT Physical Function composite MIC | Raw Mean (SD) | 162 | 6.4 (11.0) | 214 | 12.7 (16.4) | 98 | 19.6 (20.9) | 121 | 21.5 (21.2) | 50 | 27.0 (21.9) | 71 | 30.4 (23.8) | 76 | 39.7 (25.3) | 2**,3***,4***,5***,6***,8*,9**,10 ***,11***,15***,18*** | ||
LS Mean (SE) | 162 | 7.8 (1.5) | 214 | 12.6 (1.3) | 98 | 19.0 (1.9) | 121 | 21.0 (1.7) | 50 | 26.0 (2.6) | 71 | 29.3 (2.2) | 76 | 37.6 (2.2) | 29.16 | < .0001 | ||
IWQOL-Lite-CT Psychosocial composite MIC | Raw Mean (SD) | 213 | 7.9 (14.8) | 172 | 12.6 (15.1) | 122 | 20.8 (18.5) | 89 | 29.0 (18.2) | 57 | 33.5 (20.6) | 40 | 46.7 (19.6) | 49 | 54.9 (21.4) | 2***,3***,4***,5***,6***,7*,8*** ,9***,10***,11***,13**,14***,15 ***,17***,18***,19*,20*** | ||
LS Mean (SE) | 213 | 8.3 (1.2) | 172 | 12.8 (1.3) | 122 | 20.4 (1.6) | 89 | 28.2 (1.8) | 57 | 32.7 (2.3) | 40 | 45.4 (2.7) | 49 | 53.8 (2.5) | 56.53 | < .0001 | ||
IWQOL-Lite-CT Total Score MIC | Raw Mean (SD) | 181 | 5.8 (10.5) | 192 | 13.8 (16.5) | 162 | 20.4 (19.3) | 83 | 28.6 (18.4) | 66 | 37.5 (20.1) | 27 | 40.7 (13.5) | 39 | 60.3 (22.6) | 1**,2***,3***,4***,5***,6***,8*** ,9***,10***,11***,13***,14*** ,15***,18***,20***,21** | ||
LS Mean (SE) | 181 | 6.2 (1.3) | 192 | 14.0 (1.2) | 162 | 20.0 (1.3) | 83 | 27.9 (1.8) | 66 | 36.6 (2.1) | 27 | 39.3 (3.2) | 39 | 58.7 (2.7) | 59.25 | < .0001 | ||
APPADL MIC | Raw Mean (SD) | 127 | 9.5 (16.3) | 180 | 15.8 (21.1) | 61 | 18.3 (19.7) | 59 | 17.8 (22.0) | 96 | 21.4 (19.1) | 48 | 20.8 (18.8) | 128 | 35.5 (25.1) | 4*,6***,11***,15**,18***,20** ,21** | ||
LS Mean (SE) | 127 | 9.9 (1.8) | 180 | 16.5 (1.5) | 61 | 18.6 (2.6) | 59 | 17.2 (2.6) | 96 | 21.0 (2.0) | 48 | 18.9 (2.9) | 128 | 33.2 (1.8) | 18.62 | < .0001 | ||
Weight change MIC (10%) | Raw Mean (SD) | 99 | 12.4 (17.1) | 252 | 13.3 (17.0) | 250 | 15.7 (20.8) | 181 | 21.9 (24.1) | 63 | 31.1 (25.4) | 35 | 26.9 (22.1) | 18 | 41.2 (24.2) | 4***,6**,8*,9***,11**,13***,15** | ||
LS Mean (SE) | 99 | 12.7 (2.0) | 252 | 13.7 (1.3) | 250 | 15.6 (1.3) | 181 | 21.5 (1.5) | 63 | 29.2 (2.5) | 35 | 24.2 (3.4) | 18 | 37.0 (4.7) | 17.81 | < .0001 |
Anchor | Mean Type | 0 Point | 1 point | 2 points | 3 points | 4 points | F | p-value | (p-value) | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
N | Mean | N | Mean | N | Mean | N | Mean | N | Mean | |||||||||
IWQOL-Lite-CT Item 7 d,e | Raw Mean (SD) | 541 | 10.0 (15.9) | 182 | 22.6 (18.2) | 123 | 34.5 (23.0) | 31 | 48.4 (24.6) | 17 | 47.1 (34.1) | 1***,2***,3***,4***,5***,6***,7** *,8** | ||||||
LS Mean (SE) | 541 | 10.7 (0.8) | 182 | 21.3 (1.3) | 123 | 33.0 (1.6) | 31 | 46.4 (3.2) | 17 | 44.4 (4.4) | 56.83 | < .0001 | ||||||
IWQOL-Lite-CT Item 20 d,e | Raw Mean (SD) | 557 | 9.9 (15.9) | 167 | 24.2 (18.8) | 92 | 33.3 (20.0) | 45 | 45.6 (20.5) | 26 | 51.0 (30.5) | 1***,2***,3***,4***,5**,6***,7*** ,8*,9*** | ||||||
LS Mean (SE) | 557 | 10.4 (0.7) | 167 | 23.4 (1.4) | 92 | 31.9 (1.8) | 45 | 43.1 (2.7) | 26 | 49.4 (3.5) | 63.13 | < .0001 |
Distribution-based approaches
Scale | Transformed score improvement (0–100 points) | IW-SP raw scale units improvement (1–5-point scale) | Total # of response categories Improved across all three items | ||||||
---|---|---|---|---|---|---|---|---|---|
Estimation | Confirmation | Difference | Estimation | Confirmation | Difference | Estimation | Confirmation | Difference | |
IWQOL-Lite-CT Physical b | 16.80 | 16.70 | 0.10 | 0.67 | 0.67 | 0.00 | 2.03 | 2.03 | 0.00 |
IWQOL-Lite-CT Physicalb Function | 19.60 | 21.10 | − 1.50 | 0.78 | 0.84 | − 0.06 | 2.36 | 2.55 | − 0.19 |
IWQOL-Lite-CT Psychosocialb,c | 20.80 | 22.30 | − 1.50 | 0.83 | 0.89 | − 0.06 | 2.52 | 2.70 | − 0.18 |
IWQOL-Lite-CT Totalb | 20.40 | 20.80 | − 0.40 | 0.82 | 0.83 | − 0.01 | 2.48 | 2.52 | − 0.04 |
IWQOL-Lite-CT Item #7b,c | 22.60 | 25.90 | − 3.30 | 0.90 | 1.04 | − 0.14 | 2.73 | 3.15 | − 0.42 |
IWQOL-Lite-CT Item #20b,c | 24.20 | 26.90 | − 2.70 | 0.97 | 1.08 | − 0.11 | 2.94 | 3.27 | − 0.33 |
APPADL Total | 18.30 | 17.30 | 1.00 | 0.73 | 0.69 | 0.04 | 2.21 | 2.09 | 0.12 |
Distribution, 1/2 SD | 15.03 | 15.30 | − 0.27 | 0.60 | 0.61 | − 0.01 | 1.82 | 1.85 | − 0.03 |
Weight change (10%)d | 15.70 | 19.10 | − 3.40 | 0.63 | 0.76 | − 0.13 | 1.91 | 2.30 | − 0.39 |
Mean (SD) | 19.72 (3.0) | 20.79 (4.2) | − 1.07 (1.5) | 0.79 (0.1) | 0.83 (0.2) | − 0.04 (0.1) | 2.39 (0.4) | 2.52 (0.5) | − 0.13 (0.2) |
Minimum score | 15.03 | 15.30 | − 3.30 | 0.60 | 0.61 | − 0.14 | 1.82 | 1.85 | − 0.42 |
Maximum score | 24.20 | 26.90 | 1.00 | 0.97 | 1.08 | 0.04 | 2.94 | 3.27 | 0.12 |