Table 2.
Mean scores on Alzheimer’s Disease Cooperative Study-activities of daily living (ADCS-ADL) scale at baseline and at 12 and 24 months. Values are means (standard deviations) unless stated otherwise
| Variables | ADCS-ADL score (0-78) | Crude change or estimate | P values | ||
|---|---|---|---|---|---|
| Baseline | 12 months | 24 months | |||
| Descriptive data*: | |||||
| Intervention group | 53.0 (15.6); n=548 | 49.4 (17.6); n=328 | 43.4 (18.4); n=224 | — | — |
| Control group | 51.1 (16.3); n=546 | 46.7 (17.1); n=315 | 42.4 (18.1); n=257 | — | — |
| Analysis using imputation of group mean values for missing data†: | |||||
| Intervention group (n=574) | 53.0 (15.2) | 49.5 (13.4) | 43.4 (11.6) | −9.6 (15.1)‡ | — |
| Control group (n=557) | 51.1 (16.2) | 46.5 (14.2) | 42.0 (13.0) | −9.1 (15.5)‡ | 0.990 |
| Analysis with no imputation for missing data§: | |||||
| Group effect (intervention v control) | — | — | — | 1.157 | 0.46 |
| Time effect (years) | — | — | — | −5.956 | <0.001 |
| Interaction group×time | — | — | — | 0.226 | 0.78 |
*Only patients with scores.
†Missing data handled by imputing mean value of group to which patients were allocated plus analysis using mixed model, taking into account clustering effect.
‡Score at 24 months minus score at baseline.
§Mixed model taking into account both longitudinal nature of data and correlation induced by randomisation of clusters. Intervention effect assessed through interaction term that expresses how intervention influences time effect. Annual decrease for ADCS-ADL score was thus −5.96 in control group versus −5.73 in intervention group.