Table 4.
Predictive performance of seven cognitive impairment definitions for mortality
| Deaths/participants | Death rate per 1000 person-years | Mean years of follow-up (SD) | HR (95% CI) | R2 (95% CI) | AIC | Δ AIC | Sensitivity | Specificity | C-statistic (95% CI) |
p value for difference in C-statistic |
|||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Definition 1 (ref) | Demographic model (ref) | ||||||||||||
| Cognitive impairment definitions | |||||||||||||
| Definition 1 | |||||||||||||
| No cognitive impairment | 508/4866 | 9·8 | 10·6 (1·8) | 1 (ref) | 0·027 (0·011–0·050) | 11058·3 | 0 (ref) | 22·1% | 86·5% | 0·540 (0·524–0·556) | NA | <0·0001 | |
| Cognitive impairment | 141/821 | 16·7 | 10·3 (2·2) | 1·71 (1·42–2·06) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 2 | |||||||||||||
| No cognitive impairment | 400/4202 | 8·9 | 10·7 (1·7) | 1 (ref) | 0·050 (0·026–0·080) | 11 033·2 | −25·1 | 38·4% | 75·5% | 0·566 (0·547–0·585) | 0·024 | <0·0001 | |
| Cognitive impairment | 249/1485 | 16·3 | 10·3 (2·1) | 1·84 (1·57–2·16) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 3 | |||||||||||||
| No cognitive impairment | 572/5349 | 10·1 | 10·6 (1·8) | 1 (ref) | 0·036 (0·015–0·066) | 11 048·4 | −9·9 | 12·2% | 94·9% | 0·533 (0·520–0·545) | 0·21 | <0·0001 | |
| Cognitive impairment | 77/338 | 22·9 | 9·9 (2·5) | 2·31 (1·82–2·93) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 4 | |||||||||||||
| No cognitive impairment | 505/4850 | 9·8 | 10·6 (1·8) | 1 (ref) | 0·028 (0·010–0·052) | 11 057·4 | −0·9 | 22·7% | 86·3% | 0·542 (0·526–0·557) | 0·79 | <·0001 | |
| Cognitive impairment | 144/837 | 16·7 | 10·3 (2·2) | 1·71 (1·43–2·07) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 5 | |||||||||||||
| No cognitive impairment | 569/5340 | 10·1 | 10·6 (1·8) | 1 (ref) | 0·038 (0·016–0·067) | 11 045·8 | −12·5 | 12·7% | 94·7% | 0·534 (0·522–0·547) | 0·36 | <0·0001 | |
| Cognitive impairment | 80/347 | 23·2 | 10·0 (2·5) | 2·35 (1·86–2·96) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 6 | |||||||||||||
| No cognitive impairment | 514/4861 | 10·0 | 10·6 (1·8) | 1 (ref) | 0·020 (0·518–0·549) | 11 065·7 | 7·4 | 21·0% | 86·3% | 0·534 (0·518–0·549) | 0·29 | <0·0001 | |
| Cognitive impairment | 135/826 | 15·8 | 10·3 (2·2) | 1·60 (1·32–1·93) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 7 | |||||||||||||
| No cognitive impairment | 569/5333 | 10·1 | 10·6 (1·8) | 1 (ref) | 0·037 (0·016–0·065) | 11 047·8 | −10·5 | 12·7% | 94·6% | 0·534 (0·521–0·546) | 0·35 | <0·0001 | |
| Cognitive impairment | 80/354 | 22·7 | 10·0 (2·5) | 2·29 (1·81–2·90) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Demographic model | |||||||||||||
| Age, sex, and education | 649/5687 | NA | NA | NA | 0·322 (0·267–0·385) | 10 718·0 | −340·3 | 64·8% | 71·5% | 0·708 (0·688–0·729) | <0·0001 | NA | |
The definitions of cognitive impairment are as follows: (1) age and sex threshold for poor cognitive performance; (2) cognitive decline; (3) age and sex threshold for poor cognitive performance plus cognitive decline; (4) age, sex, and education threshold for poor cognitive performance; (5) age, sex, and education threshold for poor cognitive performance plus cognitive decline; (6) age, sex, and occupation threshold for poor cognitive performance; and (7) age, sex, and occupation threshold for poor cognitive performance plus cognitive decline. HR=hazard ratio. AIC=Akaike information criterion. NA=not applicable.