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

Abstract

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 dataset 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 1.06, 95%CI:1.03-1.10) and lower cognitive score at baseline (adjusted HR for severe impairment:2.86, 95% CI:1.4-5.81), and was reduced by cholinesterase inhibitors (adjusted HR:0.54, 95% CI:0.34-0.86). Mortality risk was reduced in Māori (adjusted HR:0.40, 95% CI:0.14-1.17) and Pacific Islanders (adjusted HR:0.42, 95% CI:0.22-0.80). Compared to NZ Europeans (HR:1.07, 95% CI:0.59-1.95), antipsychotics increased the risk of death 3-fold in Pacific Islanders (adjusted HR:3.18, 95%CI:1.38-7.25). A similar effect was seen in Māori (adjusted HR:3.10, 95% CI:0.53-18.2), but this did not reach statistical significance. CONCLUSIONS:The finding that European ethnicity is independently associated with increased mortality risk in dementia replicates previous research in USA and UK. Further research is required to elucidate the mechanisms underlying the better survival rates in Māori and Pacific Islanders living with dementia in NZ. This article is protected by copyright. All rights reserved.