Table 2.
Survival analysis dementia in Lewy bodies compared with Alzheimer’s dementia
| Family | Model | Dependent variable~Predictors | LL; LR test versus preceding model (unless stated) | HR with 95% CI for each predictor; corresponding Z test |
| Group 1: using time since cognitive impairment | ||||
| C | C1 | SCI~diagnosis | –1472.4; NA | diagnosis: HR 2.29 (1.78 to 2.94); Z=6.45, p=1.1 × 10–10*** |
| C2 | SCI~diagnosis+age+sex | –1446.3; χ2 2=52.3, p=4.48 × 10–12*** | Diagnosis: HR 2.48 (1.92 to 3.19); Z=7.01, p=2.32 × 10–12***, age: HR 1.06 (1.04 to 1.08); Z=6.88, p=5.85 × 10–12***, sex: HR 1.33 (1.04 to 1.70); Z=2.30, p=0.0213* | |
| C3 | SCI~diagnosis+age+sex+frailty | –1444.5; χ2 1=3.58, p=0.0585; NS | – | |
| C4 | SCI~diagnosis+age+sex+frailty+neuroleptics | –1444.3; χ2 1=0.40, p=0.526; NS | – | |
| IC | IC1† | SCI~diagnosis+age +sex+sex×diagnosis +frailty+frailty×diagnosis +neuroleptics+neuroleptics×diagnosis |
–1440.0; versus C2: χ2 5=12.5, p=0.0281* | Diagnosis: HR 3.04 (2.00 to 4.63); Z=5.20, p=2.04 × 10–7***, age: HR 1.06 (1.04 to 1.08); Z=6.77, p=1.33 × 10–11***, sex: HR 1.11 (0.73 to 1.69); Z=0.503, p=0.615; NS sex×diagnosis: HR 1.28 (0.769 to 2.14); Z=0.951, p=0.341 frailty: HR 1.83 (1.21 to 2.75); Z=2.88, p=0.00403** frailty×diagnosis: HR 0.558 (0.329 to 0.945); Z=–2.17, p=0.0301* neuroleptics: HR 1.60 (0.994 to 2.58); Z=1.94, p=0.0529; NS neuroleptics×diagnosis: HR 0.587 (0.334 to 1.03); Z=–1.85, p=0.0646; NS |
| Group 2: using time since diagnosis | ||||
| D | D1 | SDX~diagnosis | –1483.0; NA | Diagnosis: HR 2.20 (1.71 to 2.82); Z=6.18, p=6.59 × 10–10*** |
| D2 | SDX~diagnosis+age+sex | –1461.6; χ2 2=42.8, p=5.13 × 10–10*** | Diagnosis: HR 2.31 (1.80 to 2.97); Z=6.54, p=6.22 × 10–11***, age: HR 1.05 (1.04 to 1.07); Z=6.21, p=5.34 × 10–10***, sex: HR 1.37 (1.07 to 1.75); Z=2.52, p=0.0119* | |
| D3 | SDX~diagnosis+age+sex+frailty | –1459.4; χ2 1=4.47, p=0.0346* | Diagnosis: HR 2.30 (1.79 to 2.95); Z=6.49, p=8.39 × 10–11*** age: HR 1.05 (1.03 to 1.07); Z=6.02, p=1.73 × 10–9***, sex: HR 1.34 (1.05 to 1.72); Z=2.36, p=0.0181*, frailty: HR 1.32 (1.03 to 1.71); Z=2.15, p=0.0316* | |
| D4 | SDX~diagnosis+age+sex+frailty+neuroleptics | –1459.2; χ2 1=0.34, p=0.562; NS | – | |
| ID | ID1 | SDX~diagnosis+age +sex+sex×diagnosis +frailty+frailty×diagnosis +neuroleptics+neuroleptics×diagnosis |
–1453.5; versus D3: χ2 4=11.8, p=0.0186* | Diagnosis: HR 2.93 (1.92 to 4.45); Z=5.01, p=5.52 × 10–7***, age: HR 1.05 (1.04 to 1.07); Z=6.15, p=7.92 × 10–10***, sex: HR 1.11 (0.73 to 1.69); Z=0.513, p=0.608; NS sex×diagnosis: HR 1.33 (0.799 to 2.21); Z=1.09, p=0.274; NS frailty: HR 1.87 (1.24 to 2.83); Z=2.98, p=0.00287**, frailty×diagnosis: HR 0.559 (0.330 to 0.947); Z=–2.16, p=0.0307*, neuroleptics: HR 1.82 (1.13 to 2.91); Z=2.48, p=0.0133*, neuroleptics×diagnosis: HR 0.492 (0.281 to 0.862); Z=–2.48, p=0.0131* |
Table 2 Stepwise model comparisons. Times and ages are calculated in years. The effect for ‘diagnosis’ is that of Lewy body dementia (vs Alzheimer’s disease); that for ‘sex’ is maleness (vs femaleness); ‘frailty’ is the dichotomised Charlson frailty index. ‘Age’ is, throughout, the age at presentation with cognitive impairment. HR (exponentiated model coefficient).
*p<0.05; **p<0.01; ***p<0.001.
†Overall preferred model.
LL, log-likelihood; LR, likelihood ratio; NA, not applicable; NS, not significant; SCI, survival time from presentation with cognitive impairment (or diagnosis if not known); SDX, survival time from diagnosis.