Table 2 Rate of response and association of responses to individual questions about knee OA with symptomatic knee osteoarthritis (n = 1464)
From: Validation of a screening questionnaire for hip and knee osteoarthritis in old people
Question | n | Frequency of positive findings, % | Sensitivity,% (95% CI) | Specificity,% (95% CI) | Positive Predictive Value,% (95% CI) | Negative Predictive Value,% (95% CI) | Odds ratio (95% CI) | C statistics |
|---|---|---|---|---|---|---|---|---|
1. – During the last 12 months, have you often had pain in one or both your knees for one month or more? | 1413 | 80.96 | 94.77 (93.17, 96.37) | 34.48 (30.87, 38.09) | 61.80 (58.98, 64.62) | 85.50 (81.29, 89.71) | 9.54 (9.66, 13.67) | 0.646 |
2. – Has a doctor ever told you that you have osteoarthritis in one or both of your knees? | 1419 | 62.86 | 80.70 (77.87,83.53) | 56.91 (53.17, 60.65) | 67.49 (64.42, 70.56) | 72.68 (68.88, 76.48) | 5.52 (4.35, 7.00) | 0.688 |
3. – Do you have a prosthesis in one or both of your knees? | 1414 | 3.75 | 6.76 (4.95, 8.57) | 99.55 (99.04,100.1) | 94.34 (88.12, 100.6) | 49.30 (46.64, 51.96) | 16.21 (5.03, 52.21) | 0.532 |
4. – Have you had any surgical intervention in one or both of your knees? | 1415 | 11.38 | 16.40 (13.73, 19.07) | 94.09 (92.31, 95.87) | 75.16 (68.49, 81.83) | 50.80 (48.03, 53.57) | 3.12 (2.15, 4.54) | 0.552 |
5. – During the last 12 months, have you had stiffness in one or both your knees for one month or more? | 1417 | 48.98 | 64.37 (60.92, 67.82) | 67.90 (64.38, 71.42) | 68.73 (65.28, 72.18) | 63.49 (59.98, 67.00) | 3.82 (3.07, 4.77) | 0.661 |
6. – During the last 12 months, have you had any of the following limitations because of pain or stiffness in one or both of your knees? |  |  |  |  |  |  |  |  |
   6 a. – Rising from a chair or toilet | 1360 | 61.91 | 78.58 (75.58, 81.58) | 56.79 (52.96, 60.62) | 67.10 (63.93, 70.27) | 70.27 (66.33, 74.21) | 4.82 (30.80 6.11) | 0.677 |
   6 b. – Going up steps | 1380 | 69.71 | 85.44 (82.88, 88.00) | 47.85 (44.02, 51.68) | 64.66 (61.64, 67.68) | 74.64 (70.47, 78.81) | 5.38 (4.16, 6.96) | 0.666 |
   6 c. – Going down steps | 1374 | 70.74 | 88.05 (85.69, 90.41) | 48.76 (44.91, 52.61) | 65.95 (62.97, 68.93) | 78.36 (74.33, 82.39) | 7.01 (5.34, 9.20) | 0.684 |
   6d. – Walking 4 blocks (or 500 m) | 1348 | 55.34 | 70.72 (67.37, 74.07) | 61.62 (57.86, 65.38) | 67.02 (63.65, 70.39) | 65.61 (61.82, 69.40) | 3.88 (3.09, 4.87) | 0.662 |
7. – During the last 12 months, have you often experienced any sensation of insecurity or that one or both of your knees failed? | 1394 | 62.55 | 77.05 (74.00, 80.10) | 53.47 (49.67, 57.27) | 64.68 (61.51, 67.85) | 67.82 (63.81, 71.83) | 3.86 (3.07, 4.86) | 0.653 |