Table 1.
Comparison of the three instruments using clinical assessment as the ‘gold standard’
| Instrument | Cut-off point | Sensitivity (%) | Specificity (%) | Positive predictive value | Negative predictive value | Likelihood ratio |
|---|---|---|---|---|---|---|
| IQCODE | >3 | 100.0 | 0 | 37.8 | 0 | 1.0 |
| >3.5 | 71.4 | 82.6 | 71.4 | 82.6 | 4.1 | |
| >4 | 42.8 | 95.6 | 85.7 | 73.3 | 9.8 | |
| CDR | >0.5 | 85.7 | 17.4 | 38.7 | 66.6 | 1.0 |
| >1 | 57.1 | 86.9 | 71.7 | 76.9 | 4.3 | |
| >2 | 28.6 | 95.6 | 80.0 | 68.7 | 6.6 | |
| >3 | 21.4 | 95.6 | 75.0 | 66.6 | 4.9 | |
| MMSE | <17 | 35.7 | 91.3 | 71.4 | 70.0 | 4.1 |
| <20 | 50.0 | 82.6 | 63.6 | 73.0 | 2.8 | |
| <23 | 64.3 | 65.2 | 52.9 | 75.0 | 1.8 |