L ong-term residential aged care (RAC) is used at any one time by about 4-6% of those aged 65 years or over in many developed countries, including NZ. [1][2][3] This figure -usually derived from research adopting cross-sectional methods such as censuses and surveys -sometimes leads to the erroneous assumption that only few people use RAC during their lifetimes. 4 Inappropriate use of cross-sectional figures for estimating the likelihood of use of RACwhich Kastenbaum and Candy referred to as "the four per cent fallacy" 5,6 -may suggest that the sector is small and affects few people. To avoid such misunderstandings, and for policy and planning purposes, estimates are needed of the likelihood people aged 65 and over will use residential care at any time before they die, hereafter termed 'lifetime use' .Studies of place of death have been used to answer this question. 5,[7][8][9] Deaths in RAC are widely available, based on death certificate information. For example, a large international comparison of 21 populations aged 65+ years showed RAC was the place of death for a median of 18% (inter-quartile range 14-29 %) of decedents 10 . In the US the proportion was 29% and in Australia and Canada 32%, but in Iceland and NZ the proportion was higher at 38%. However, deaths in RAC underestimate total RAC use wherever a proportion of RAC residents die in an acute hospital.Other than place of death, three methodologies have previously been used to assess lifetime use. These include 1) assembling a population-representative cohort and following it either prospectively until death or from death retrospectively; 2) using the lifetable method as used in demographic projections; and 3) modelling transition probabilities between residence at home, residence in RAC and death, and then simulating lifetime risk. All these methods require the assembly of large or long cohorts. In countries where there are no such cohorts, including NZ, another method of estimation is required. The need for simple methods to estimate lifetime use has previously been recognised. 9 This paper describes a simple method of estimation of lifetime use of RAC for people who reach the age of 65 years. Administrative data for place of death obtained from death certificates are obtained first for the NZ population, derived from all death certificates over a five-year period. To that figure is added an estimate of the number of RAC residents who die, not in RAC, but in acute hospital. It then compares NZ estimates to published reports for other countries. Methods: Deaths of RAC residents in acute hospitals were estimated for NZ from four separate studies and added to deaths occurring in RAC, to derive the likelihood of using RAC after age 65 years. Academic and other sources were searched for comparative reports.
Likelihood of residential agedResults: An estimated 18% of RAC residents died in acute hospital in NZ. When added to those who died in RAC, the proportion using RAC for late-life care was estimated at over 47% (66% if aged 85+ years). Of 12 US reports,...