Anti-dementia medication use in Aotearoa New Zealand: An exploratory study using health data from the Integrated Data Infrastructure (IDI).

OBJECTIVE: Anti-dementia medications such as acetylcholinesterase inhibitors are an important part of the management pathway for dementia. However, there are limited data in New Zealand that have examined the rates and patterns of use of funded anti-dementia medication and how use differs with ethnicity, age and sex. METHODS: This was a retrospective population-based descriptive study. Using the Integrated Data Infrastructure, we identified individuals of all ages coded for a diagnosis of dementia and estimated the proportion dispensed funded anti-dementia medication - donepezil tablets and rivastigmine patches - between 1 July 2016 and 30 June 2020. Rates of medication use in five main ethnic groups (Maori, Pacific peoples, Asian, European, and Middle Eastern, Latin American and African) in the <65, 65-79 and 80 and over (80+) age groups were compared and also between males and females in all sub-groups. Log-binomial models were used to calculate relative risks to determine any differences in anti-dementia medication use in the five ethnic groups and the three age groups and between males and females in each of the four study years. RESULTS: Overall, one-third of the dementia population received a funded anti-dementia medication in the total population (all ages) between 2016 and 2020. Donepezil tablets were dispensed in 31.6-34.0% and rivastigmine patches in 1.4-2.1% across the four study years. Compared to people of European ethnicity, Maori, Pacific peoples, and Middle Eastern, Latin American and African groups were less likely to be dispensed an anti-dementia medication (Maori: relative risk = 0.79-0.81, p < 0.0001; Pacific peoples: relative risk = 0.72-0.74, p < 0.0001; Middle Eastern, Latin American and African: relative risk = 0.73-0.78, p < 0.05). Compared to the age 80+ group, the 65-79 age group was more likely (relative risk = 1.50-1.54, p < 0.0001), while the age <65 group was less likely (relative risk = 0.67-0.71, p < 0.0001) to be dispensed an anti-dementia medication. There were no statistically significant differences in anti-dementia medication use between males and females. CONCLUSION: This study provides important information about funded anti-dementia medication use in New Zealand and how this differs by ethnicity, age and sex. Despite higher dementia prevalence in Maori and Pacific peoples, these groups were less likely to receive funded anti-dementia medication.

Prevalence of young-onset dementia: nationwide analysis of routinely collected data.

INTRODUCTION: Young-onset dementia prevalence is understudied internationally. Previous studies have been limited by low case numbers, reliance on single sources of routinely collected health data for case identification and inclusion of a limited age range. Our objective was to determine the 1-year period prevalence of diagnosed dementia in people aged 0-64 in the entire New Zealand population using routinely collected health data. METHODS: A population-based descriptive study was carried out in New Zealand (population 4.8 million) using routinely collected deidentified health data from 2016 to 2020. Dementia cases in seven linked health datasets in the New Zealand Integrated Data Infrastructure were identified using diagnostic codes and/or use of antidementia medication. Prevalence for each of the four study years was calculated by age, sex and ethnicity. RESULTS: From a total population of 4 027 332-4 169 754 individuals aged 0-64, we identified 3396-3474 cases of 'all-cause' dementia in each of the study years (prevalence crude range: 83-84/100 000 people aged 0-64; 139-141/100 000 people aged 30-64 years; 204-207/100 000 people aged 45-64 years). Age-standardised prevalence was higher in males than females. Age-standardised and sex-standardised prevalence was higher in Maori and Pacific People than European and Asian. DISCUSSION: By using a large study population and multiple national health datasets, we have minimised selection bias and estimated the national prevalence of diagnosed young-onset dementia with precision. Young-onset dementia prevalence for the total New Zealand population was similar to reported global prevalence, validating previous estimates. Prevalence differed by ethnicity, which has important implications for service planning.

Dementia prevalence estimation among the main ethnic groups in New Zealand: a population-based descriptive study of routinely collected health data.

OBJECTIVE: Estimates of dementia prevalence in New Zealand (NZ) have previously been extrapolated from limited Australasian studies, which may be neither accurate nor reflect NZ's unique population and diverse ethnic groups. This study used routinely collected health data to estimate the 1-year period prevalence for diagnosed dementia for each of the 4 years between July 2016 and June 2020 in the age 60+ and age 80+ populations and for the four main ethnic groups. DESIGN: A population-based descriptive study. SETTING: Seven national health data sets within the NZ Integrated Data Infrastructure (IDI) were linked. Diagnosed dementia prevalence for each year was calculated using the IDI age 60+ and age 80+ populations as the denominator and also age-sex standardised to allow comparison across ethnic groups. PARTICIPANTS: Diagnosed dementia individuals in the health datasets were identified by diagnostic or medication codes used in each of the data sets with deduplication of those who appeared in more than one data set. RESULTS: The crude diagnosed dementia prevalence was 3.8%-4.0% in the age 60+ population and 13.7%-14.4% in the age 80+ population across the four study years. Dementia prevalence age-sex standardised to the IDI population in the last study period of 2019-2020 was 5.4% for Maori, 6.3% for Pacific Islander, 3.7% for European and 3.4% for Asian in the age 60+ population, and 17.5% for Maori, 22.2% for Pacific Islander, 13.6% for European and 13.5% for Asian in the age 80+ population. CONCLUSIONS: This study provides the best estimate to date for dementia prevalence in NZ but is limited to those people who were identified as having dementia based on data from the seven included data sets. The findings suggest that diagnosed dementia prevalence is higher in Maori and Pacific Islanders. A nationwide NZ community-based dementia prevalence study is much needed to confirm the findings of this study.