Predictors of mortality in Māori, Pacific Island, and European patients diagnosed with dementia at a New Zealand Memory Service

Background: As the economic impact of dementia on health and social care increases, governments require disease-specific epidemiological data that will help inform spending and policy decisions. The aim of this study is to examine predictors of mortality in dementia in consecutive referrals to a New Zealand (NZ) memory service that includes Māori, Pacific Islander, and NZ European patients.

Methods: Date of birth, sex, ethnicity, living situation, cognitive function, dementia subtype, dementia severity, physical comorbidity, and medication data were collected from electronic health records. The resulting data set was linked to administrative data on mortality and last hospital contact dates to allow time-dependent survival analyses.

Results: The risk of death in people with dementia was increased by age (adjusted HR per year 1.08, 95%CI:1.05-1.12) and lower cognitive score at baseline (adjusted HR for severe impairment:2.54, 95% CI:1.25-5.16), and was reduced by cholinesterase inhibitors (adjusted HR:0.54, 95% CI:0.34-0.88). Compared to NZ Europeans (HR:1.19, 95% CI:0.63-2.25), antipsychotics increased the risk of death three-fold in Māori (adjusted HR:3.62, 95% CI:0.79-16.7) and Pacific Islanders (adjusted HR:2.54, 95%CI:1.10-5.85).

Conclusions: Further research is required to elucidate the mechanisms underlying the survival rates in Māori and Pacific Islanders living with dementia in NZ,and their increased risk of death if antipsychotics are used.