Table 1.
Performance of the individual components of the Michigan Neuropathy Screening Instrument (MNSI) questionnaire and examination in predicting confirmed clinical neuropathy
| Confirmed clinical neuropathy |
Sensitivity | Specificity | χ2-test* P-value |
|||
|---|---|---|---|---|---|---|
| Questionnaire | No | Yes | ||||
| 1. Are your legs and/or feet numb? | No | 790 | 231 | 34.6% | 95.5% | 192.1 |
| Yes | 37 | 122 | < 0.01 | |||
| 2. Do you ever have any burning pain in your legs and/or feet? | No | 765 | 267 | 25.0% | 92.7% | 70.9 |
| Yes | 60 | 89 | < 0.01 | |||
| 3. Are your feet too sensitive to touch? | No | 812 | 326 | 8.4% | 98.2% | 29.7 |
| Yes | 15 | 30 | < 0.01 | |||
| 4. Do you get muscle cramps in your legs and/or feet? | No | 613 | 203 | 42.8% | 74.1% | 33.3 |
| Yes | 214 | 152 | < 0.01 | |||
| 5. Do you ever have any prickling feelings in your legs or feet? | No | 724 | 221 | 37.6% | 87.6% | 97.8 |
| Yes | 103 | 133 | < 0.01 | |||
| 6. Does it hurt when the bedcovers touch your skin? | No | 812 | 332 | 6.7% | 98.3% | 20.4 |
| Yes | 14 | 24 | < 0.01 | |||
| 7. When you get into the bath or shower, are you able to tell the hot water from the cold water?† | No | 46 | 52 | 14.6% | 94.4% | 26.8 |
| Yes | 781 | 304 | < 0.01 | |||
| 8. Have you ever had an open sore on your foot? | No | 712 | 258 | 27.3% | 86.2% | 30.9 |
| Yes | 114 | 97 | < 0.01 | |||
| 9. Has your doctor ever told you that you have diabetic neuropathy? | No | 724 | 180 | 49.2% | 87.9% | 190.1 |
| Yes | 100 | 174 | < 0.01 | |||
| 10. Do you feel weak all over most of the time? | No | 809 | 324 | 9.0% | 97.7% | 27.1 |
| Yes | 19 | 32 | < 0.01 | |||
| 11. Are your symptoms worse at night? | No | 750 | 276 | 22.0% | 91.1% | 38.4 |
| Yes | 73 | 78 | < 0.01 | |||
| 12. Do your legs hurt when you walk? | No | 782 | 299 | 15.8% | 94.6% | 33.9 |
| Yes | 45 | 56 | < 0.01 | |||
| 13. Are you able to sense your feet when you walk?† | No | 75 | 39 | 11.0% | 90.9% | 1.0 |
| Yes | 752 | 317 | 0.31 | |||
| 14. Is the skin on your feet so dry that it cracks open? | No | 732 | 292 | 18.0% | 88.6% | 9.4 |
| Yes | 94 | 64 | < 0.01 | |||
| 15. Have you ever had an amputation? | No | 822 | 340 | 4.2% | 99.5% | 22.0 |
| Yes | 4 | 15 | < 0.01 | |||
| Examination | ||||||
| 1. Is the appearance of at least one foot abnormal? | No | 586 | 186 | 47.3% | 71.5% | 38.7 |
| Yes | 234 | 167 | < 0.01 | |||
| 2. Is ulceration present in at least one foot? | No | 817 | 348 | 2.0% | 99.5% | 5.9 |
| Yes | 4 | 7 | 0.02 | |||
| 3. Are the ankle reflexes reduced in both feet or absent in at least one foot? | No | 538 | 99 | 71.8% | 65.8% | 139.8 |
| Yes | 280 | 252 | < 0.01 | |||
| 4. Is vibration perception reduced in both feet or absent in at least one foot? | No | 617 | 149 | 58.2% | 75.2% | 121.2 |
| Yes | 204 | 207 | < 0.01 | |||
*
Testing that the proportion ‘yes’ on the MNSI questionnaire or examination is the same for those with and without confirmed clinical neuropathy.
†
Questions 7 and 13 were reversed scored so that ’no‘ responses indicated an abnormality and counted as one point in the scoring algorithms. The sensitivities and specificities are based on the reversed 2 × 2 tables.