Table 1.
Baseline characteristics of the study participants (OAI subjects with baseline knee osteoarthritis defined as radiographic Kellgren-Lawrence grade ≥ 2) before and after propensity score matching according to the presence of DM
| Characteristic variables | All patients with KOA |
PS-matched patients with KOA |
||||
|---|---|---|---|---|---|---|
| No. of thighs\knees | DM (−) N: 2324 | DM (+) N: 200 | SMD | DM (−) N: 513 | DM (+) N: 185 | SMD |
|
| ||||||
| Subject characteristics | ||||||
| Age (year) (mean (SD)) | 62.18 (8.97) | 63.37 (8.28) | 0.137 | 64.01 (8.63) | 63.52 (8.16) | 0.059 |
| No. of women (N (%)) | 1346 (57.9) | 120 (60.0) | 0.042 | 300 (58.5) | 114 (61.6) | 0.064 |
| Race, non-White (N (%)) † | 512 (22.0) | 84 (42.0) | 0.438 | 193 (37.6) | 76 (41.1) | 0.071 |
| Comorbidities and risk factors | ||||||
| PASE score (mean (SD)) | 161.77 (79.89) | 130.27 (67.60) | 0.426 | 130.21 (73.23) | 134.36 (67.75) | 0.059 |
| BMI (kg/m2) (mean (SD)) | 29.23 (4.78) | 32.09 (4.79) | 0.598 | 31.76 (4.82) | 31.84 (4.73) | 0.017 |
| Abdominal (central) obesity (N (%))‡ | 1720 (74.0) | 182 (91.0) | 0.459 | 460 (89.7) | 167 (90.3) | 0.020 |
| Hypertension (N (%)) | 548 (23.6) | 60 (30.0) | 0.145 | 158 (30.8) | 56 (30.3) | 0.011 |
| CVA (N (%)) | 70 (3.0) | 17 (8.5) | 0.237 | 28 (5.5) | 13 (7.0) | 0.065 |
| Heart attack (N (%)) | 42 (1.8) | 8 (4.0) | 0.131 | 16 (3.1) | 4 (2.2) | 0.060 |
| Heart failure (N (%)) | 42 (1.8) | 12 (6.0) | 0.218 | 28 (5.5) | 8 (4.3) | 0.053 |
| Peripheral artery disease (N (%)) | 18 (0.8) | 2 (1.0) | 0.024 | 10 (1.9) | 2 (1.1) | 0.071 |
| Malignancy (N (%)) | 87 (3.7) | 22 (11.0) | 0.280 | 40 (7.8) | 18 (9.7) | 0.068 |
| Advanced liver disease (N (%)) | 1 (0.0) | 0 (0.0) | 0.029 | 1 (0.2) | 0 (0.0) | 0.062 |
| Kidney dysfunction (N (%)) | 16 (0.7) | 8 (4.0) | 0.220 | 12 (2.3) | 5 (2.7) | 0.023 |
| COPD (N (%)) | 40 (1.7) | 12 (6.0) | 0.223 | 15 (2.9) | 8 (4.3) | 0.075 |
| Peptic ulcer (N (%)) | 46 (2.0) | 18 (9.0) | 0.312 | 26 (5.1) | 14 (7.6) | 0.099 |
| KL grade (N (%)) | 0.089 | 0.051 | ||||
| Grade 2 | 1502 (64.6) | 122 (61.0) | 331 (64.5) | 115 (62.2) | ||
| Grade 3 | 672 (28.9) | 66 (33.0) | 149 (29.0) | 58 (31.4) | ||
| Grade 4 | 150 (6.5) | 12 (6.0) | 33 (6.4) | 12 (6.5) | ||
| Medial JSN grade (N (%)) | 0.195 | 0.061 | ||||
| Grade 0 | 862 (37.1) | 58 (29.0) | 159 (31.0) | 56 (30.3) | ||
| Grade 1 | 852 (36.7) | 76 (38.0) | 201 (39.2) | 69 (37.3) | ||
| Grade 2 | 518 (22.3) | 54 (27.0) | 120 (23.4) | 48 (25.9) | ||
| Grade 3 | 92 (4.0) | 12 (6.0) | 33 (6.4) | 12 (6.5) | ||
| Medications | ||||||
| Diuretic (N (%)) | 468 (20.1) | 66 (33.0) | 0.294 | 154 (30.0) | 58 (31.4) | 0.029 |
| β blocker (N (%)) | 350 (15.1) | 50 (25.0) | 0.250 | 113 (22.0) | 48 (25.9) | 0.092 |
| Calcium channel blocker (N (%)) | 238 (10.2) | 46 (23.0) | 0.348 | 103 (20.1) | 38 (20.5) | 0.011 |
| Lipid-lowering drug (N (%)) | 592 (25.5) | 118 (59.0) | 0.721 | 285 (55.6) | 103 (55.7) | 0.002 |
| NSAID (N (%)) | 456 (19.6) | 30 (15.0) | 0.122 | 86 (16.8) | 30 (16.2) | 0.015 |
| Aspirin (N (%)) | 58 (2.5) | 18 (9.0) | 0.282 | 30 (5.8) | 12 (6.5) | 0.027 |
| SSRI(N (%)) | 174 (7.5) | 18 (9.0) | 0.055 | 47 (9.2) | 16 (8.6) | 0.018 |
| Tricyclic antidepressant (N (%)) | 34 (1.5) | 6 (3.0) | 0.104 | 7 (1.4) | 5 (2.7) | 0.095 |
| Sedative (N (%)) | 112 (4.8) | 12 (6.0) | 0.052 | 22 (4.3) | 12 (6.5) | 0.097 |
| Systemic corticosteroid (N (%)) | 188 (8.1) | 16 (8.0) | 0.003 | 32 (6.2) | 12 (6.5) | 0.010 |
| Thyroid hormones (N (%)) | 248 (10.7) | 28 (14.0) | 0.101 | 62 (12.1) | 24 (13.0) | 0.027 |
| Antineoplastic agents (N (%)) | 64 (2.8) | 6 (3.0) | 0.015 | 15 (2.9) | 6 (3.2) | 0.018 |
| Anticoagulants (N (%)) | 58 (2.5) | 6 (3.0) | 0.031 | 17 (3.3) | 6 (3.2) | 0.004 |
| Insulin* (N (%)) | 0 (0.0) | 26 (13.0) | 0.547 | 0 (0.0) | 21 (11.4) | 0.506 |
| Oral hypoglycemic* (N (%)) | 0 (0.0) | 142 (71.0) | 2.191 | 0 (0.0) | 131 (70.8) | 2.139 |
| KOA symptoms* | ||||||
| WOMAC pain score (mean (SD)) | 2.54 (3.35) | 3.74 (4.16) | 0.318 | 3.25 (3.86) | 3.49 (3.95) | 0.061 |
| WOMAC disability score (mean (SD)) | 8.60 (10.85) | 12.62 (13.18) | 0.334 | 10.96 (12.74) | 11.70 (12.30) | 0.059 |
| WOMAC stiffness score (mean (SD)) | 1.61 (1.64) | 2.14 (1.92) | 0.299 | 1.88 (1.81) | 2.02 (1.83) | 0.095 |
| WOMAC total score (mean (SD)) | 12.75 (15.11) | 18.51 (18.57) | 0.340 | 16.00 (17.68) | 17.20 (17.33) | 0.069 |
| Thigh muscle MRI biomarkers* | ||||||
| Quadriceps CSA (mm2) (mean (SD)) | 5091.74 (1378.60) | 5229.28 (1292.57) | 0.103 | 5302.82 (1332.89) | 5199.58 (1248.95) | 0.080 |
| Quadriceps intra-MAT CSA (mm2) (mean (SD)) | 190.12 (147.46) | 258.59 (178.21) | 0.419 | 233.91 (154.97) | 251.70 (179.28) | 0.106 |
| Quadriceps contractile muscle % (mean (SD)) | 96.11 (3.10) | 94.86 (3.54) | 0.374 | 95.40 (3.23) | 94.99 (3.54) | 0.122 |
| Flexor CSA (mm2) (mean (SD)) | 3342.22 (867.66) | 3382.40 (780.03) | 0.049 | 3453.75 (864.56) | 3344.16 (749.55) | 0.135 |
| Flexor intra-MAT CSA (mm2) (mean (SD)) | 182.55 (155.11) | 262.44 (225.85) | 0.412 | 220.85 (172.35) | 254.58 (222.42) | 0.170 |
| Flexor contractile % (mean (SD)) | 94.46 (4.39) | 92.28 (5.70) | 0.430 | 93.54 (4.61) | 92.42 (5.66) | 0.216 |
| Adductor CSA (mm2) (mean (SD)) | 1208.43 (621.89) | 1318.76 (645.52) | 0.174 | 1318.00 (641.73) | 1304.16 (641.52) | 0.022 |
| Adductor intra-MAT CSA (mm2) (mean (SD)) | 74.29 (69.80) | 93.83 (62.30) | 0.295 | 92.89 (71.32) | 90.15 (60.79) | 0.041 |
| Adductor contractile % (mean (SD)) | 93.25 (4.75) | 92.08 (4.75) | 0.247 | 92.24 (5.00) | 92.28 (4.67) | 0.009 |
| Sartorius CSA (mm2) (mean (SD)) | 385.94 (141.67) | 431.69 (146.53) | 0.317 | 424.69 (152.33) | 424.11 (145.59) | 0.004 |
| Sartorius intra-MAT CSA (mm2) (mean (SD)) | 34.41 (29.78) | 49.84 (34.98) | 0.475 | 45.92 (36.48) | 47.71 (34.31) | 0.050 |
| Sartorius contractile % (mean (SD)) | 91.13 (6.31) | 88.58 (6.27) | 0.405 | 89.21 (6.68) | 88.86 (6.23) | 0.054 |
| Total thigh muscle CSA (mm2) (mean (SD)) | 10028.33 (2650.01) | 10362.13 (2476.21) | 0.130 | 10499.26 (2586.65) | 10272.01 (2383.85) | 0.091 |
| Intra-MAT CSA (mm2) (mean (SD)) | 481.38 (346.97) | 664.69 (420.80) | 0.475 | 593.57 (365.26) | 644.13 (417.29) | 0.129 |
| Total thigh muscle contractile muscle % | 95.09 (3.27) | 93.45 (3.94) | 0.453 | 94.22 (3.38) | 93.61 (3.93) | 0.167 |
Data are presented in numbers of thighs\knees. A significant difference for SMD was defined as ≥ 0.1 and is shown in bold. ACEI angiotensin-converting enzyme inhibitor, ARB angiotensin receptor blocker, BMI body mass index, CSA cross-sectional area, COPD chronic obstructive pulmonary disease, CVA cerebrovascular accident, DM diabetes mellitus, intra-MAT intra-muscular adipose tissue, KL Kellgren-Lawrence grade, N Newton, NSAIDs nonsteroidal anti-inflammatory drugs, PASE Physical Activity for Elderly Scale, PS propensity score, SMD standardized mean difference, SD standard deviation, SSRI selective serotonin reuptake inhibitor, WOMAC Western Ontario and McMaster Universities Osteoarthritis Index
These variables were not included in the PS matching
Race of participants was categorized as White and non-White considering the small number of participants in each non-White race group
Abdominal obesity was defined as a waist circumference of ≥ 94 cm in men and ≥ 80 cm in women on physical examination according to international DM foundation criteria