Table 3.
Predictive performance of seven cognitive impairment definitions for dementia
| Cases/participants | Dementia 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 | 179/4866 | 3·7 | 10·1 (1·7) | 1 (ref) | 0·155 (0·088–0·238) | 4527·9 | 0 (ref) | 32·9% | 86·6% | 0·608 (0·580–0·637) | NA | <0·0001 | |
| Cognitive impairment | 91/821 | 11·6 | 9·5 (2·4) | 3·26 (2·53–4·19) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 2 | |||||||||||||
| No cognitive impairment | 136/4202 | 3·2 | 10·1 (1·7) | 1 (ref) | 0·169 (0·102–0·248) | 4521·4 | −6·5 | 48·4% | 75·1% | 0·631 (0·601–0·660) | 0·23 | <0·0001 | |
| Cognitive impairment | 134/1485 | 9·4 | 9·6 (2·3) | 3·01 (2·37–3·82) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 3 | |||||||||||||
| No cognitive impairment | 210/5349 | 3·9 | 10·1 (1·8) | 1 (ref) | 0·200 (0·117–0·292) | 4506·3 | −21·6 | 21·8% | 94·9% | 0·592 (0·566–0·617) | 0·09 | <0·0001 | |
| Cognitive impairment | 60/338 | 19·8 | 9·0 (2·9) | 5·30 (3·98–7·07) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 4 | |||||||||||||
| No cognitive impairment | 175/4850 | 3·6 | 10·1 (1·7) | 1 (ref) | 0·169 (0·099–0·257) | 4521·0 | −6·9 | 34·3% | 86·4% | 0·612 (0·583–0·641) | 0·64 | <0·0001 | |
| Cognitive impairment | 95/837 | 11·9 | 9·5 (2·5) | 3·39 (2·64–4·36) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 5 | |||||||||||||
| No cognitive impairment | 207/5340 | 3·9 | 10·1 (1·8) | 1 (ref) | 0·214 (0·130–0·311) | 4499·2 | −28·7 | 22·4% | 94·8% | 0·595 (0·569–0·621) | 0·25 | <0·0001 | |
| Cognitive impairment | 63/347 | 20·2 | 9·0 (2·9) | 5·48 (4·13–7·26) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 6 | |||||||||||||
| No cognitive impairment | 178/4861 | 3·6 | 10·1 (1·8) | 1 (ref) | 0·155 (0·088–0·234) | 4527·7 | −0·2 | 32·5% | 86·5% | 0·608 (0·579–0·637) | 0·99 | <0·0001 | |
| Cognitive impairment | 92/826 | 11·6 | 9·6 (2·4) | 3·25 (2·52–4·17) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Definition 7 | |||||||||||||
| No cognitive impairment | 209/5333 | 3·9 | 10·1 (1·8) | 1 (ref) | 0·194 (0·115–0·285) | 4509·0 | −18·9 | 21·6% | 94·6% | 0·591 (0·565–0·616) | 0·15 | <0·0001 | |
| Cognitive impairment | 61/354 | 19·0 | 9·0 (2·9) | 5·08 (3·82–6·76) | .. | .. | .. | .. | .. | .. | .. | .. | |
| Demographic model | |||||||||||||
| Age, sex, and education | 270/5687 | NA | NA | NA | 0·543 (0·465–0·626) | 4312·6 | −215·3 | 74·2% | 72·2% | 0·783 (0·758–0·809) | <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.