Subgroup analyses
Alzheimer’s disease, dementia, cognitive impairment
VASCULAR DEMENTIA, FRONTOTEMPORAL DEMENTIA, LEWY BODY DISEASE, POLAND, NEURODEGENERATIVE DISEASES
Exploratory subgroup analyses will be performed for the primary outcome, NPI-Q severity at 90 days and 180 days post-randomisation. The following subgroups will be explored: (i) gender of PwD (male, female); (ii) gender of CG (male, female); (iii) type of dementia (neurodegenerative diseases [Alzheimer’s disease, frontotemporal dementia, Lewy body disease], mixed [vascular dementia, mixed dementia], other [other or unknown]); (iv) severity of dementia of PwD at baseline (no cognitive impairment [MMSE score of 24–30], mild cognitive impairment [19–23], moderate cognitive impairment [10–18], severe cognitive impairment [< 10]); (v) time of onset dementia (early [under 65 years old] vs late [≥ 65 years old]); (vi) length of time PwD has had dementia (years); (vii) CG’s relationship to PwD (spouse or partner, child or other [sibling, friend, other]); and (viii) country (Australia [Northern Australia and Southern Australia combined], Norway, the UK, Poland, Germany).For each subgroup analysis, the subgroup (main effect) and its interaction with the intervention group at each time point will be included in the unadjusted longitudinal data analysis model. This will enable the evaluation of whether the treatment effect differs between subgroup categories. Results of the subgroup analyses will be displayed using forest plots, presenting the estimate and two-sided 95% CI of the treatment effect within each subgroup level and the 