Background
Methods
Item bank development
Sampling and data collection
Pre-Identified Disease Group | Pre-Identified Combined (N = 5418) | Gen. Pop. Chronically Ill (N = 4120) | |||||
---|---|---|---|---|---|---|---|
Arthritis (N = 1574) | CKD (N = 299) | Cardiovascular (N = 639) | Diabetes (N = 1326) | Respiratory (N = 1580) | |||
Age | |||||||
Mean (SD) | 62.1 (11.2) | 63.5 (12.8) | 65.7 (10.7) | 60.3 (11.9) | 53.0 (16.1) | 59.5 (13.7) | 50.9 (16.0) |
Median | 63 | 64 | 66 | 61 | 55 | 61 | 52 |
Range | 20–93 | 18–92 | 18–97 | 18–92 | 18–93 | 18–97 | 18–94 |
% Male | 35.5 | 51.8 | 56.6 | 52.0 | 35.2 | 42.8 | 47.0 |
Race/Ethnicity | |||||||
White non-Hispanic | 82.5 | 81.6 | 84.5 | 77.6 | 77.0 | 79.9 | 77.3 |
Black non-Hispanic | 6.9 | 8.0 | 5.3 | 11.1 | 7.3 | 7.9 | 8.9 |
Hispanic | 5.3 | 5.0 | 2.7 | 6.2 | 7.6 | 5.9 | 8.4 |
Other non-Hispanic | 5.3 | 5.4 | 7.5 | 5.1 | 8.1 | 6.3 | 5.4 |
Education | |||||||
< High school graduate | 2.6 | 4.7 | 5.6 | 2.6 | 3.4 | 3.3 | 7.3 |
High school graduate | 20.5 | 11.7 | 16.3 | 19.1 | 17.8 | 18.4 | 26.5 |
Some college | 34.1 | 41.8 | 41.9 | 39.7 | 38.2 | 38.0 | 31.6 |
College graduate | 42.8 | 41.8 | 36.2 | 38.6 | 40.6 | 40.3 | 34.6 |
Income | |||||||
< $20,000 | 11.6 | 15.1 | 14.9 | 10.6 | 13.7 | 12.5 | 13.8 |
$20,000–39,999 | 21.6 | 24.4 | 26.8 | 21.9 | 18.7 | 21.6 | 21.4 |
$40,000–99,999 | 47.4 | 44.8 | 47.4 | 52.0 | 48.0 | 48.6 | 41.8 |
$100,000+ | 19.4 | 15.7 | 10.9 | 15.5 | 19.6 | 17.3 | 23.0 |
Employment Status | |||||||
Employed | 35.9 | 23.7 | 20.0 | 43.4 | 47.0 | 38.4 | 52.4 |
Unemployed | 4.0 | 1.7 | 2.8 | 4.8 | 5.1 | 4.3 | 7.0 |
Retired due to age | 38.0 | 40.5 | 42.4 | 33.0 | 21.1 | 32.5 | 19.3 |
Disableda
| 12.8 | 24.4 | 26.5 | 10.2 | 12.3 | 14.3 | 7.7 |
Otherb
| 8.7 | 8.7 | 7.4 | 7.7 | 13.9 | 9.8 | 13.1 |
Missing | 0.6 | 1.0 | 0.9 | 0.8 | 0.5 | 0.7 | 0.5 |
Analyses
Unidimensionality and item local dependence
Differential item functioning
Item Response Theory (IRT) modeling
Item bank reduction and short form development
Reliability
Validity
Responsiveness
Norm-based T-score transformation
Results
Sample characteristics
Item descriptive statistics
Ordera
| Areab
| Abbreviated Contentc
| N | Mean (SD) | rd
| ae
| b Rangee
| Fitf
| Imax at Θg
| CATh
|
---|---|---|---|---|---|---|---|---|---|---|
1**
| QL | Everyday activity, QOLi
| 5399 | 1.80 (1.04) | .956 | 3.55 | 0.18–2.11 | 191.9 | 6.26 (1.20) | 100 |
44 | QL | Activity enjoyment lifei
| 4044 | 1.79 (1.03) | .946 | 2.63 | 0.20–2.28 | 151.0 | 4.20 (1.10) | 0 |
2**
| HO | Worry health future | 5372 | 2.11 (1.13) | .844 | 1.49 | −0.10–1.86 | 371.9 | 1.90 (1.35) | 42 |
36*
| HO | Concern worry | 4022 | 1.90 (1.08) | .868 | 1.84 | 0.13–1.97 | 284.2 | 2.65 (1.55) | 28 |
10**
| PF | Usual physical activities | 4019 | 1.96 (1.12) | .920 | 3.10 | 0.00–1.93 | 158.2 | 4.76 (1.45) | 55 |
3*
| PF | Physical activity walking | 5386 | 1.95 (1.20) | .876 | 2.20 | 0.25–1.64 | 148.5 | 4.11 (1.15) | 0 |
47*
| MB | Stay inside house | 4008 | 1.57 (1.04) | .894 | 2.41 | 0.87–1.94 | 132.5 | 5.60 (1.20) | 0 |
27**
| RL | Work daily activities | 4015 | 1.87 (1.09) | .964 | 5.30 | 0.08–1.89 | 114.4 | 9.67 (1.40) | 64 |
5*
| RL | Everyday activities | 5381 | 1.77 (1.06) | .957 | 4.67 | 0.26–1.96 | 101.6 | 8.64 (1.50) | 41 |
15*
| RL | Get done work home | 4026 | 1.91 (1.14) | .940 | 3.88 | 0.11–1.83 | 123.6 | 6.97 (1.50) | 14 |
17*
| RL | Cancel work activity | 4015 | 1.42 (0.85) | .921 | 3.47 | 0.88–2.17 | 71.9 | 7.46 (1.95) | 2 |
23*
| RL | Limited usual activities | 4006 | 1.77 (1.04) | .948 | 4.50 | 0.20–1.97 | 89.2 | 8.70 (1.65) | 14 |
26*
| RL | Accomplished less | 5395 | 1.97 (1.16) | .937 | 3.88 | 0.07–1.78 | 85.9 | 6.94 (1.40) | 28 |
30*
| RL | Leisure activities | 4017 | 1.35 (0.75) | .873 | 2.47 | 1.05–2.49 | 152.9 | 4.35 (2.15) | <1 |
33*
| RL | Productive work other | 4012 | 1.54 (1.00) | .945 | 4.12 | 0.72–1.96 | 44.9 | 9.81 (1.00) | 26 |
49*
| RL | Daily work in and out | 3995 | 1.84 (1.09) | .954 | 4.52 | 0.14–1.88 | 101.5 | 8.73 (1.60) | 34 |
8 | RL | Daily tasks help | 4020 | 1.72 (1.06) | .856 | 1.93 | 0.55–1.94 | 183.1 | 3.37 (1.35) | 0 |
13 | RL | Usual daily activitiesj
| 4020 | 1.73 (1.01) | .941 | 4.14 | 0.25–2.14 | 107.0 | 7.12 (1.30) | 0 |
19 | RL | Stop work other activity | 4012 | 1.75 (1.02) | .911 | 3.09 | 0.27–2.05 | 89.1 | 5.38 (1.75) | 0 |
35 | RL | Simple tasks hard | 4006 | 1.81 (1.08) | .923 | 3.58 | 0.22–1.93 | 104.6 | 6.48 (1.60) | 0 |
38 | RL | Keep from traveling | 4017 | 1.46 (0.97) | .916 | 2.42 | 1.11–1.95 | 177.0 | 6.32 (1.30) | 0 |
41 | RL | Restrict recreational | 4014 | 1.48 (0.90) | .897 | 2.64 | 0.87–2.17 | 122.5 | 5.04 (1.20) | 0 |
42 | RL | Cut down amount time | 4011 | 1.68 (1.04) | .942 | 3.97 | 0.43–1.97 | 72.7 | 7.73 (1.70) | <1 |
6**
| SA | Social family friends | 5383 | 1.56 (0.96) | .950 | 4.56 | 0.57–2.04 | 107.1 | 9.69 (1.75) | 30 |
37*
| SA | Enjoying social activities | 4007 | 1.60 (0.98) | .945 | 4.34 | 0.52–2.08 | 93.3 | 8.29 (1.65) | 19 |
45*
| SA | Hard to get along with | 4006 | 1.52 (0.87) | .853 | 2.05 | 0.75–2.43 | 208.3 | 3.26 (1.65) | <1 |
9 | SA | Enjoyment family friends | 4020 | 1.63 (0.98) | .915 | 3.05 | 0.50–2.19 | 93.0 | 5.16 (0.90) | 0 |
14 | SA | Avoid social activities | 5399 | 1.55 (0.97) | .938 | 3.59 | 0.68–2.12 | 67.9 | 7.52 (1.00) | 0 |
21 | SA | Uncomfortable people | 4015 | 1.43 (0.85) | .890 | 2.57 | 0.93–2.09 | 135.7 | 5.54 (1.85) | 0 |
32 | SA | Travel take trip | 4012 | 1.52 (1.02) | .915 | 2.48 | 0.98–1.82 | 75.8 | 6.53 (1.30) | 0 |
40 | SA | Family social leisurek
| 4015 | 1.40 (0.80) | .920 | 3.33 | 0.92–2.60 | 81.8 | 6.73 (1.10) | 1 |
4**
| FT | Worn out, tired | 5384 | 1.94 (1.13) | .923 | 3.41 | 0.06–1.81 | 96.5 | 6.17 (1.45) | 19 |
28*
| FT | Bed most of day | 4018 | 1.30 (0.73) | .878 | 2.37 | 1.34–2.42 | 124.8 | 5.23 (1.60) | <1 |
18 | FT | Need lie down rest | 4012 | 1.92 (1.12) | .884 | 2.44 | 0.16–1.92 | 124.9 | 3.71 (0.55) | 0 |
46 | FT | Too tired to workj
| 4007 | 1.70 (0.98) | .932 | 4.01 | 0.26–2.22 | 107.4 | 6.70 (1.35) | <1 |
20*
| SL | Good night sleep | 5387 | 1.94 (1.14) | .810 | 1.52 | 0.31–1.86 | 294.0 | 2.27 (1.15) | 26 |
11**
| EM | Frustrated fed up | 4011 | 2.03 (1.21) | .871 | 1.99 | 0.14–1.74 | 209.3 | 3.12 (0.70) | 36 |
7*
| EM | Bothered emotionally | 5378 | 1.67 (1.00) | .906 | 2.04 | 0.53–2.00 | 117.4 | 3.71 (1.60) | 0 |
16*
| EM | Interest enjoyment | 4018 | 1.81 (1.07) | .940 | 4.26 | 0.20–2.01 | 110.6 | 7.19 (0.60) | 17 |
22 | EM | Losing control life | 4006 | 1.56 (0.97) | .898 | 2.35 | 0.78–1.99 | 89.0 | 4.40 (1.70) | 0 |
24 | EM | Tense feel anxious | 4007 | 1.67 (0.99) | .895 | 2.37 | 0.46–2.07 | 107.1 | 4.07 (1.70) | 0 |
29 | EM | Fed up frustratedj
| 4032 | 1.68 (0.99) | .895 | 2.39 | 0.39–2.14 | 167.8 | 4.29 (1.45) | 0 |
31 | EM | Letting others down | 4019 | 1.58 (1.03) | .914 | 2.86 | 0.78–1.89 | 64.1 | 6.42 (1.05) | 0 |
34 | EM | Angry act irritable | 4001 | 1.63 (0.98) | .885 | 2.09 | 0.61–2.03 | 111.8 | 3.71 (1.65) | 0 |
39 | EM | Feel desperate | 4009 | 1.38 (0.82) | .904 | 2.43 | 1.08–2.25 | 114.5 | 5.25 (1.60) | 0 |
43 | EM | Depressed sad | 5388 | 1.62 (0.99) | .911 | 2.04 | 0.71–1.98 | 134.1 | 3.84 (1.50) | 0 |
25*
| CG | Difficult to focus | 4009 | 1.53 (0.89) | .921 | 3.38 | 0.60–2.20 | 91.7 | 6.63 (1.95) | <1 |
12 | CG | Focus on work | 4010 | 1.74 (1.02) | .927 | 3.68 | 0.29–2.09 | 51.6 | 6.24 (1.70) | 0 |
48 | CG | Ability to concentratej
| 4004 | 1.51 (0.86) | .923 | 3.66 | 0.60–2.36 | 69.3 | 6.48 (2.05) | 3 |
Unidimensionality and item local dependence
Disease | Confirmatory Factor Analysis | IRT parameters | Item r with theta scored
| Inter-scale correlationse
| ||||||
---|---|---|---|---|---|---|---|---|---|---|
Χ2
| df | CFI | RMSEA (90 % CI) | Factor Loadingsb
| Residualsc
| Slopes | Thresholds | |||
Arthritis | 7037 | 1127 | 0.979 | 0.077 | 0.91 | 0.026 | 2.58 | 0.99 | 0.76 | 0.9996 |
(0.076–0.079) | 0.74–0.94 | 0.00–0.143 | 1.18–4.02 | −0.83–2.72 | 0.59–0.86 | |||||
CKD | 1865 | 1127 | 0.991 | 0.058 | 0.93 | 0.026 | 3.55 | 1.36 | 0.76 | 0.9983 |
(0.053–0.062) | 0.76–0.97 | 0.00–0.202 | 1.29–5.94 | −0.24–2.38 | 0.62–0.83 | |||||
Cardiovascular | 3658 | 1127 | 0.987 | 0.069 | 0.92 | 0.022 | 3.13 | 1.18 | 0.75 | 0.9998 |
(0.067–0.072) | 0.81–0.96 | 0.00–0.141 | 1.62–5.51 | −0.20–2.71 | 0.59–0.86 | |||||
Diabetes | 3991 | 1127 | 0.985 | 0.061 | 0.91 | 0.027 | 2.98 | 1.85 | 0.70 | 0.9992 |
(0.059–0.063) | 0.81–0.97 | 0.00–0.186 | 1.36–6.05 | −0.29–2.99 | 0.51–0.81 | |||||
Respiratory | 4847 | 1127 | 0.990 | 0.060 | 0.92 | 0.021 | 3.13 | 1.50 | 0.75 | 0.9999 |
(0.058–0.061) | 0.84–0.97 | 0.00–0.124 | 1.64–5.87 | 0.10–2.67 | 0.58–0.86 | |||||
Combined | 20,669 | 1127 | 0.982 | 0.074 | 0.92 | 0.023 | 3.05 | 1.34 | 0.74 | - |
(0.073,0.075) | 0.81–0.96 | 0.00–0.158 | 1.49–5.30 | −0.10–2.60 | 0.58–0.85 |
Differential item functioning
IRT and other item-level properties
Person-level scale scores
Reliability
Disease | Mean (SD)a
| % with IRT Reliability ≥0.90 by Severity Levelb
| Alphac
| Test-retest reliabilityd
| |||
---|---|---|---|---|---|---|---|
Mild | Moderate | Severe | Total | ||||
Arthritis | 54.24 (8.72) | (N = 718) | (N = 587) | (N = 231) | (N = 1536) | .94 | .88 |
60.5 | 93.5 | 95.7 | 78.4 | ||||
CKD | 48.97 (9.17) | (N = 200) | (N = 61) | (N = 36) | (N = 297) | .94 | .91 |
34.5 | 82.0 | 94.4 | 51.5 | ||||
Cardiovascular | 51.65 (9.87) | (N = 483) | (N = 112) | (N = 36) | (N = 631) | .94 | .90 |
55.5 | 95.5 | 91.7 | 64.7 | ||||
Diabetes | 47.60 (7.75) | (N = 921) | (N = 329) | (N = 63) | (N = 1313) | .91 | .83 |
38.6 | 72.0 | 100.0 | 49.9 | ||||
Respiratory | 48.45 (9.45) | (N = 1152) | (N = 306) | (N = 112) | (N = 1570) | .94 | .88 |
36.4 | 87.3 | 93.8 | 50.4 |
Validity
Disease/Measure | Mean (SD) by Self-Evaluated Severitya
| F-ratio | RVb
| 95 % CIc
| ||
---|---|---|---|---|---|---|
Mild | Moderate | Severe | ||||
Arthritis | (N = 688) | (N = 564) | (N = 214) | |||
QDIS-7d
| 49.2 (6.88) | 57.4 (5.83) | 64.9 (5.81) | 586.27 | 1.00 | |
SF-8 PCSe
| 48.1 (7.60) | 40.9 (8.65) | 31.2 (8.22) | 383.73 | 0.65 | (0.56,0.76) |
SF-8 MCSe
| 51.8 (8.08) | 48.8 (10.19) | 44.7 (11.40) | 49.19 | 0.08 | (0.05,0.12) |
CKD | (N = 189) | (N = 56) | (N = 33) | |||
QDIS-7 | 44.7 (6.96) | 53.3 (7.72) | 61.3 (8.40) | 87.99 | 1.00 | |
SF-8 PCS | 42.2 (11.10) | 37.3 (10.61) | 33.3 (7.50) | 12.41 | 0.14 | (0.06,0.26) |
SF-8 MCS | 50.4 (9.43) | 45.6 (11.82) | 44.4 (11.33) | 8.15 | 0.09 | (0.02,0.20) |
Cardiovascular | (n = 469) | (n = 107) | (n = 35) | |||
QDIS-7 | 48.5 (8.83) | 58.9 (6.66) | 65.6 (5.60) | 123.29 | 1.00 | |
SF-8 PCS | 41.8 (10.25) | 34.2 (8.55) | 30.4 (7.21) | 43.32 | 0.35 | (0.24,0.50) |
SF-8 MCS | 49.8 (9.70) | 46.5 (10.70) | 39.1 (12.74) | 21.47 | 0.17 | (0.07,0.30) |
Diabetes | (N = 870) | (N = 317) | (N = 58) | |||
QDIS-7 | 45.3 (6.42) | 51.5 (7.21) | 59.0 (5.85) | 196.01 | 1.00 | |
SF-8 PCS | 48.4 (8.76) | 44.4 (9.93) | 40.6 (11.03) | 36.59 | 0.19 | (0.11,0.28) |
SF-8 MCS | 51.9 (8.08) | 48.4 (9.75) | 42.6 (11.49) | 44.33 | 0.23 | (0.13,0.34) |
Respiratory | (N = 1106) | (N = 297) | (N = 109) | |||
QDIS-7 | 44.7 (7.10) | 56.4 (6.71) | 64.3 (7.07) | 622.23 | 1.00 | |
SF-8 PCS | 48.1 (9.46) | 41.4 (10.20) | 33.4 (10.84) | 149.30 | 0.24 | (0.18,0.30) |
SF-8 MCS | 49.5 (9.34) | 46.4 (11.65) | 42.2 (12.06) | 32.74 | 0.05 | (0.03,0.08) |
Disease | N | Disease-specific severitya
| Disease-specific QOLb
| Generic Physicalc
| Generic Mentalc
|
---|---|---|---|---|---|
Arthritis | 925 | 0.72 | 0.71 | −0.69 | −0.44 |
CKD | 240 | 0.66 | 0.83 | −0.44 | −0.43 |
Cardiovascular | 542 | 0.65 | 0.72, 0.79 | −0.52 | −0.51 |
Diabetes | 695 | 0.54 | 0.72, 0.72 | −0.43 | −0.49 |
Respiratory | 848 | 0.74 | 0.83 | −0.58 | −0.38 |
Responsiveness
Measure | Mean change score by self-evaluated outcomea
| F-ratio | RVb
| 95 % CIc
| ||||
---|---|---|---|---|---|---|---|---|
Much better | Somewhat better | Same | Somewhat worse | Much worse | ||||
(N = 244) | (N = 245) | (N = 1181) | (N = 282) | (N = 37) | ||||
QDIS-7d
| −2.76 | −0.04 | 1.29 | 3.20 | 5.87 | 29.80 | 1.00 | - |
SF-8 PCSd
| 1.36 | −0.71 | −0.28 | −3.22 | −4.98 | 14.15 | 0.47 | (0.24,0.85) |
SF-8 MCSd
| 1.33 | −0.47 | 0.14 | −0.33 | −0.91 | 2.06 | 0.07 | (0.00,0.15) |