Alzheimer Disease and Mortality

Abstract

Background: Alzheimer disease (AD) is considered a leading cause of death, but few studies have examined the contribution of AD to mortality based on follow-up of representative US cohorts. Objective: To examine mortality rates, duration of survival, causes of death, and the contribution of AD to the risk of mortality in an aging community-based cohort, controlling for other predictors. Design: Fifteen-year prospective epidemiological study. Mortality rates per 1000 person-years and the populationattributable risk of mortality were determined. Cox proportional hazards models were used to estimate relative risk of mortality due to AD, adjusting for relevant covariates. Death certificates were abstracted for listed causes of death. Setting: A largely blue-collar rural community in southwestern Pennsylvania. Participants: A community-based cohort of 1670 adults 65 years and older at study enrollment. Main Outcome Measure: Mortality. Results: In the overall cohort, AD was a significant predictor of mortality, with a hazard ratio of 1.4 after adjusting for covariates. The population-attributable risk of mortality from AD was 4.9% based on the same model. Examining the sexes separately, AD increased mortality risk only among women. Death certificates of AD subjects were more likely to list dementia/AD, other brain disorders, pneumonia, and dehydration, and less likely to include cancer. Conclusions: Alzheimer disease was responsible for 4.9% of the deaths in this elderly cohort. Alzheimer disease increased the risk of mortality 40% in the cohort as a whole and separately in women but not in men. The mean (SD) duration of survival with AD was 5.9 (3.7) years, and longer with earlier age at onset.

Cerebral inflammation is an underlying mechanism of early death in Alzheimer’s disease: a 13-year cause-specific multivariate mortality study

“…The mean survival time of 6.4 years found here was in agreement with a large review of 42 studies on AD mortality [ 43 ]. Large differences are found in the prevalence of death causes, but overall, pneumonia and dementia have been reported most commonly [ 3 , 11 , 13 , 44 ], which differs somewhat from the results of the present study (Figure 1 ). We believe this can be explained by the manner in which the cause of death was entered on the death certificate, rather than by an actual difference in death causes.…”

Cerebral inflammation is an underlying mechanism of early death in Alzheimer’s disease: a 13-year cause-specific multivariate mortality study

“…The mean survival time of 6.4 years found here was in agreement with a large review of 42 studies on AD mortality [ 43 ]. Large differences are found in the prevalence of death causes, but overall, pneumonia and dementia have been reported most commonly [ 3 , 11 , 13 , 44 ], which differs somewhat from the results of the present study (Figure 1 ). We believe this can be explained by the manner in which the cause of death was entered on the death certificate, rather than by an actual difference in death causes.…”

Predicting sojourn times across dementia disease stages, institutionalization, and mortality

“…Participants who were older at study entry tended to progress more quickly through each stage (e.g., mild state for individuals 87 at study entry: 1.03 years) compared those younger individuals (71 at study entry: 1.28 years). This fits within previous literature, which has consistently found increased mortality and disease severity for older dementia patients 25–27 …”

Survival after dementia diagnosis in five racial/ethnic groups

“…Our finding that survival time after dementia diagnosis decreases with age at diagnosis is consistent with prior research [1, 36–38]. Estimates of median survival time after diagnosis in the present study are shorter than incident dementia cases identified in cohort studies with dementia ascertainment at pre-specified intervals or studies of prevalent dementia cases seen at memory clinics [2–4].…”

Cerebral inflammation is an underlying mechanism of early death in Alzheimer’s disease: a 13-year cause-specific multivariate mortality study

“…The mean survival time of 6.4 years found here was in agreement with a large review of 42 studies on AD mortality [ 43 ]. Large differences are found in the prevalence of death causes, but overall, pneumonia and dementia have been reported most commonly [ 3 , 11 , 13 , 44 ], which differs somewhat from the results of the present study (Figure 1 ). We believe this can be explained by the manner in which the cause of death was entered on the death certificate, rather than by an actual difference in death causes.…”

Predicting sojourn times across dementia disease stages, institutionalization, and mortality

“…Participants who were older at study entry tended to progress more quickly through each stage (e.g., mild state for individuals 87 at study entry: 1.03 years) compared those younger individuals (71 at study entry: 1.28 years). This fits within previous literature, which has consistently found increased mortality and disease severity for older dementia patients 25–27 …”

Survival after dementia diagnosis in five racial/ethnic groups

“…Our finding that survival time after dementia diagnosis decreases with age at diagnosis is consistent with prior research [1, 36–38]. Estimates of median survival time after diagnosis in the present study are shorter than incident dementia cases identified in cohort studies with dementia ascertainment at pre-specified intervals or studies of prevalent dementia cases seen at memory clinics [2–4].…”

Cerebral inflammation is an underlying mechanism of early death in Alzheimer’s disease: a 13-year cause-specific multivariate mortality study

“…The mean survival time of 6.4 years found here was in agreement with a large review of 42 studies on AD mortality [ 43 ]. Large differences are found in the prevalence of death causes, but overall, pneumonia and dementia have been reported most commonly [ 3 , 11 , 13 , 44 ], which differs somewhat from the results of the present study (Figure 1 ). We believe this can be explained by the manner in which the cause of death was entered on the death certificate, rather than by an actual difference in death causes.…”

Predicting sojourn times across dementia disease stages, institutionalization, and mortality

“…Participants who were older at study entry tended to progress more quickly through each stage (e.g., mild state for individuals 87 at study entry: 1.03 years) compared those younger individuals (71 at study entry: 1.28 years). This fits within previous literature, which has consistently found increased mortality and disease severity for older dementia patients 25–27 …”

Survival after dementia diagnosis in five racial/ethnic groups

“…Our finding that survival time after dementia diagnosis decreases with age at diagnosis is consistent with prior research [1, 36–38]. Estimates of median survival time after diagnosis in the present study are shorter than incident dementia cases identified in cohort studies with dementia ascertainment at pre-specified intervals or studies of prevalent dementia cases seen at memory clinics [2–4].…”