Table 5.
Characteristics of subjects by functional status at baseline
| Characteristic (95% confidence interval) | WOMAC function category | ||||||
|---|---|---|---|---|---|---|---|
| Baseline (n = 2946) | |||||||
| 0−5 (n = 956) |
6−9 (n = 307) |
10−19 (n = 688) |
20−29 (n = 541) |
30−39 (n = 328) |
40−68 (n = 126) |
p value | |
| Age (mean, years) | 61 (60.7, 61.7) |
62 (61.3, 63.1) |
63 (62.4, 63.6) |
63 (62.4, 63.8) |
64 (63.2, 65.0) |
61 (59.9, 62.8) |
<0.001 |
| BMI (mean, kg/m2) | 29 (28.9, 29.5) |
29 (28.8, 29.9) |
30 (29.9, 30.7) |
32 (31.6, 32.7) |
33 (32.5, 34.0) |
35 (34.0, 36.6) |
<0.001 |
| Sex (%, women) | 52 (48.4, 54.7) |
53 (47.8, 59.0) |
63 (59.5, 66.7) |
68 (63.5, 71.4) |
70 (65.2, 75.1) |
71 (63.5, 79.3) |
<0.001 |
| Race (%, white) | 89 (87.0, 91.0) |
89 (85.8, 92.7) |
88 (85.8, 90.6) |
81 (77.5, 84.1) |
70 (65.2, 75.1) |
54 (45.3, 62.7) |
<0.001 |
| College (%, yes) | 79 (76.2, 81.4) |
79 (74.3, 83.4) |
71 (68.0, 74.7) |
64 (59.9, 68.0) |
63 (58.2, 68.6) |
46 (37.3, 54.7) |
<0.001 |
| Maximum VAS pain (mean) | 4.9 (4.4, 5.5) |
15.3 (13.7, 16.9) |
23.4 (22.3, 24.5) |
38.5 (37.0, 40.1) |
54.3 (52.2, 56.4) |
74.0 (70.4, 77.7) |
<0.001 |
| CES-D (mean) | 5.2 (4.8, 5.5) |
5.8 (5.2, 6.5) |
7.0 (6.5, 7.5) |
8.2 (7.6, 8.8) |
12.2 (11.2, 13.2) |
17.3 (15.2, 19.4) |
<0.001 |
| Comorbidity: mean number | 0.3 (0.3, 0.4) |
0.4 (0.3, 0.5) |
0.5 (0.4, 0.6) |
0.6 (0.5, 0.7) |
0.8 (0.7, 0.9) |
1.1 (0.9, 1.4) |
<0.001 |
| Kellgren-Lawrence grade (%) | <0.001 | ||||||
| 0 | 51 (46.9, 55.0) |
44 (37.1, 51.1) |
29 (24.5, 33.1) |
20 (16.5, 25.1) |
16 (11.5, 21.5) |
15 (8.8, 24.7) |
|
| 1 | 19 (16.6, 23.0) |
18 (13.1, 24.0) |
17 (13.7, 20.9) |
13 (9.8, 17.0) |
11 (7.4, 16.0) |
13 (7.6, 22.8) |
|
| 2 | 15 (12.3, 18.1) |
16 (11.1, 21.5) |
19 (15.9, 23.4) |
18 (13.9, 22.0) |
13 (9.4, 18.8) |
16 (9.4, 25.6) |
|
| 3-4 | 15 (11.9, 17.6) |
22 (17.1, 28.9) |
35 (30.6, 39.7) |
49 (43.7, 54.3) |
60 (52.9, 66.3) |
56 (44.5, 66.1) |
|
| Characteristic (95% confidence interval) | 30 month visit (N=2495) | ||||||
|---|---|---|---|---|---|---|---|
| 0−5 (n = 874) |
6−9 (n = 290) |
10−19 (n = 565) |
20−29 (n = 424) |
30−39 (n = 230) |
40−68 (n = 112) |
||
| Age (mean, years) | 64 (63.4, 64.4) |
64 (63.4, 65.4) |
65 (64.2, 65.5) |
66 (65.5, 67.0) |
66 (65.2, 67.3) |
64 (62.4, 65.3) |
<0.001 |
| BMI (mean, kg/m2) | 29 (29.0, 29.7) |
29 (28.7, 29.9) |
31 (30.2, 31.2) |
32 (31.1, 32.3) |
32 (31.6, 33.1) |
35 (33.4, 36.1) |
<0.001 |
| Sex (%, women) | 52 (48.5, 55.1) |
65 (59.0, 70.0) |
61 (57.4, 65.4) |
64 (59.3, 68.5) |
71 (65.5, 77.2) |
68 (59.2, 76.5) |
<0.001 |
| Race (%, white) | 88 (86.1, 90.4) |
90 (86.9, 93.7) |
89 (86.1, 91.3) |
83 (79.7, 86.8) |
79 (73.4, 84.0) |
61 (51.7, 69.8) |
<0.001 |
| College (%, yes) | 79 (76.2, 81.7) |
82 (77.3, 86.2) |
72 (68.3, 75.7) |
68 (63.0, 71.9) |
53 (46.2, 59.1) |
60 (50.7, 68.9) |
<0.001 |
| Maximum VAS pain (mean) | 4.8 (4.2, 5.4) |
14.5 (13.1, 16.0) |
22.5 (21.3, 23.8) |
38.2 (36.3, 40.0) |
52.7 (50.1, 55.2) |
73.1 (69.2, 76.9) |
<0.001 |
| CES-D (mean) | 4.4 (4.0, 4.8) |
6.1 (5.3, 6.8) |
6.9 (6.4, 7.5) |
8.6 (7.9, 9.4) |
10.9 (9.8, 11.9) |
17.3 (14.9, 19.7) |
<0.001 |
| Comorbidity (mean number) | 0.4 (0.3, 0.5) |
0.4 (0.3, 0.5) |
0.6 (0.5, 0.6) |
0.8 (0.7, 0.9) |
0.7 (0.5, 0.9) |
1.2 (1.0, 1.5) |
<0.001 |
| Kellgren-Lawrence grade (%) | <0.001 | ||||||
| 0 | 52 (47.8, 56.3) |
39 (32.1, 46.3) |
28 (23.8, 33.3) |
20 (15.6, 25.3) |
18 (12.4, 25.0) |
15 (8.6, 25.5) |
|
| 1 | 17 (14.2, 20.6) |
19 (13.6, 25.0) |
15 (11.4, 18.8) |
10 (6.6, 13.9) |
10 (6.4, 16.6) |
7 (3.1, 15.7) |
|
| 2 | 14 (11.1, 16.9) |
16 (11.5, 22.3) |
19 (15.2, 23.4) |
15 (11.3, 19.9) |
13 (8.5, 19.6) |
11 (5.4, 20.2) |
|
| 3−4 | 17 (14.1, 20.5) |
26 (20.3, 33.1) |
38 (33.1, 43.3) |
55 (49.1, 61.1) |
59 (50.5, 66.5) |
67 (55.2, 76.9) |
|
BMI = body mass index; VAS = visual analog scale; CES-D = Center for Epidemiologic Studies Depression Scale.