Table 3:
Maximal Likelihood Ratio (LR) Chi-Square (χ2) Approachd to identify the optimal threshold of walking speed measured via a 2.4-m walk test in the Johnston County Osteoarthritis Project (JoCoOA; A) and a 20-m walk test in the Osteoarthritis Initiative (OAI) and Multicenter Osteoarthritis Study (MOST;B), OAI only (C) and MOST only (D) cohorts that predicted the risk of excess mortality and diagnostic evaluation of thresholds in adults with radiographic knee osteoarthritis (rKOA).
| Thresholds | Number of deaths/Total people (%) | aHR[95% CI] | bLR χ2 | Diagnostic Evaluation Value[95%CI] |
||||
|---|---|---|---|---|---|---|---|---|
| Walk <threshold | Walk ≥threshold | Sensitivity | Specificity | Negative LR | Positive LR | |||
| (A) 2.4-m (short-distance) walk test administered in the JoCoOA | ||||||||
| 0.4 m/s | 54/132 (40.9) | 236/1112 (21.2) | a1.69[1.23, 2.33] | 24.8 | 18.6[14.3, 23.6] | 91.8[89.9, 93.5] | 0.89[0.84, 0.94] | 2.3[1.7, 3.1] |
| e0.5 m/s | 94/243 (38.4) | 196/1001 (19.6) | a1.60[1.22, 2.11] | e38.0 | 32.4[27.1, 38.1] | 84.4[81.9, 86.6] | 0.80[0.74, 0.87] | 2.1[1.7, 2.6] |
| 0.6 m/s | 141/430 (32.3) | 149/814 (18.3) | a1.44[1.11, 1.88] | 31.9 | 48.6[42.7, 54.5] | 69.7[66.7, 72.6] | 0.74[0.65, 0.83] | 1.6[1.4, 1.9] |
| 0.7 m/s | 191/649 (29.4) | 99/595 (16.6) | a1.50[1.14, 1.97] | 30.0 | 65.9[60.1, 71.3] | 52.0[48.8, 55.2] | 0.66[0.55, 0.78] | 1.4[1.2, 1.5] |
| (B) 20-m (standard-distance) walk test administered in the OAI and MOST | ||||||||
| 1.0 m/s | 53/537 (9.9) | 196/3678 (5.3) | a,c1.42[1.00, 2.02] | 20.7 | 21.3[16.4, 26.9] | 87.8[86.7, 88.8] | 0.90[0.84, 0.96] | 1.7[1.4, 2.3] |
| 1.1 m/s | 101/1035 (9.8) | 148/3180 (4.7) | a,c1.76[1.31, 2.36] | 43.5 | 40.6[34.4, 46.9] | 76.5[75.1, 77.8] | 0.78[0.70, 0.86] | 1.7[1.5, 2.0] |
| e1.2 m/s | 153/1738 (8.8) | 96/2477 (3.9) | a,c1.96[1.47, 2.62] | e57.5 | 61.5[55.1, 67.5] | 60.0[58.5, 61.6] | 0.64[0.55, 0.75] | 1.5[1.4, 1.7] |
| 1.3 m/s | 186/2514 (7.4) | 63/1701 (3.7) | a,c1.61[1.18, 2.21] | 37.6 | 74.7[68.8, 80.0] | 58.7[57.2, 60.2] | 0.43[0.35, 0.53] | 1.8[1.7, 2.0] |
| (C) 20-m (standard-distance) walk test administered in the OAI only | ||||||||
| 1.0 m/s | 27/205 (13.2) | 140/2353 (6.0) | a1.71[1.08, 2.70] | 14.5 | 16.2[10.9, 22.6] | 92.6[91.4, 93.6] | 0.91[0.85, 0.97] | 2.2[1.5, 3.2] |
| 1.1 m/s | 51/438 (11.6) | 116/2119 (5.5) | a1.71[1.18, 2.48] | 22.0 | 30.5[23.7, 38.1] | 83.8[82.3, 85.3] | 0.83[0.75, 0.92] | 1.9[1.5, 2.4] |
| e1.2 m/s | 90/816 (11.0) | 77/1741 (4.4) | a2.05[1.46, 2.89] | e40.3 | 53.9[46.0, 61.6] | 69.6[67.7, 71.5] | 0.66[0.56, 0.78] | 1.8[1.5, 2.1] |
| 1.3 m/s | 116/1264 (9.2) | 51/1293 (3.9) | a1.78[1.25, 2.55] | 32.4 | 69.5[61.9, 76.3] | 52.0[49.9, 54.0] | 0.59[0.47, 0.74] | 1.5[1.3, 1.6] |
| (D) 20-m (standard-distance) walk test administered in the MOST only | ||||||||
| 1.0 m/s | 26/332 (7.8) | 56/1326 (4.2) | a1.09[0.63, 1.90] | 6.8 | 31.7[21.9, 42.9] | 80.6[78.5, 82.5] | 0.85[0.73, 0.98] | 1.6[1.2, 2.3] |
| e1.1 m/s | 50/597 (8.4) | 32/1061 (3.0) | a1.98[1.21, 3.25] | e22.1 | 61.0[49.6, 71.6] | 65.3[62.9, 67.6] | 0.60[0.45, 0.79] | 1.8[1.5, 2.1] |
| 1.2 m/s | 63/922 (6.8) | 19/736 (2.6) | a1.89[1.08, 3.32] | 17.2 | 76.8[66.2, 85.4] | 45.5[43.0, 48.0] | 0.51[0.34, 0.76] | 1.4[1.2, 1.6] |
| 1.3 m/s | 70/1250 (5.6) | 12/408 (2.9) | a1.25[0.65, 2.41] | 5.6 | 85.4[75.8, 92.2] | 25.1[23.0, 27.4] | 0.58[0.34, 0.99] | 1.1[1.0, 1.3] |
Note. m/s=meters/second
Adjusted for baseline age, body mass index, sex, race, education, comorbidities, depression (≤ vs. >16), and symptomatic knee OA (yes or no)
LR χ2 values are obtained from unadjusted Cox models for (A), (C) and (D) and from Cox model stratified by study orgin was used in (B)
Cox model stratified by study oirigin (OAI or MOST) was used when the data from OAI and MOST cohorts were combined into one sample
Approach states that higher chi-square values represent greater concordance between the threshold and mortality
Model that yielded a maximum χ2 value
aHR=adjusted hazard ratio, CI=confidence interval