The influence of socioeconomic deprivation on dementia mortality, age at death and quality of diagnosis: a nationwide death records study in England and Wales 2001-2017

Background Socioeconomic deprivation is postulated to be an important determinant of dementia risk, mortality, and access to diagnostic services. Nevertheless, premature mortality from other causes and under-representation of deprived individuals in research cohorts may lead to this effect being overlooked. Methods We obtained Office of National Statistics (ONS) mortality data where dementia was recorded as a cause of death in England and Wales from 2001 to 2017, stratified by age, diagnosis code and UK Index of Multiple Deprivation (IMD) decile. We calculated standardised mortality ratios (SMR) for each IMD decile, adjusting for surviving population size in each IMD decile and age stratum. In those who died of dementia, we used ordinal logistic regression to examine the effect of deprivation on likelihood of being older at death. We used logistic regression to test the effect of deprivation on likelihood of receiving a diagnosis of unspecified dementia, a proxy for poor access to specialist diagnostic care. Results 578,623 deaths due to dementia in people over the age of 65 were identified between 2001-2017. SMRs were similar across the three most deprived deciles (1-3) but progressively declined through deciles 4-10 (Mean SMR [95%CI] in decile 1: 0.528 [0.506 to 0.550], decile 10: 0.369 [0.338 to 0.400]). This effect increased over time with improving ascertainment of dementia. In 2017, 14,837 excess dementia deaths were attributable to deprivation (21.5% of the total dementia deaths that year). There were dose-response effects of deprivation on likelihood of being older at death with dementia (odds ratio [95%CI] for decile 10 (least deprived): 1.31 [1.28 to 1.33] relative to decile 1), and on likelihood of receiving a diagnosis of unspecified dementia (odds ratio [95%CI] for decile 10: 0.78 [0.76 to 0.80] relative to decile 1). Conclusions Socioeconomic deprivation in England and Wales is associated with increased dementia mortality, younger age at death with dementia, and poorer access to specialist diagnosis. Reducing social inequality may be an important strategy for prevention of dementia mortality.