Risk And Factors Of AD Mortality:A Meta-analysis

Background:Although there were many studies on the pathogenesis and risk factors of Alzheimer’s Disease(AD),with the growing number of elderly population around the world,the death caused from AD had been increasing.Methods:We aimed to perform a meta-analysis on the risk and factors of AD mortality.We searched database of Pub Med and Cochrane systematically till November nineteenth,2018,and reviewed the reference lists of included studies and relevant reviews identified in the search.We calculated effect sizes for relative risk(RR)with a95%CI(confidence interval)via random-effects model.The heterogeneity of results was represented by the statistic I~2,and the sources of heterogeneity were explored by subgroup analysis,Meta regression and sensitivity analysis.Results:22 articles reporting risk of AD mortality and eligible for meta-analysis were included with a pooled RR 2.12(95%CI=1.88-2.38;I~2=90%).35 articles were identified reporting factors of AD mortality,and we found 12 factors could increase the risk of AD mortality including age at entry,diabetes mellitus,congestive heart failure,ischemic heart disease,stroke,hallucination,depression,delirium,aphasia,gait disturbance,extrapyramidal symptoms and urinary incontinence,3 factors could decrease the risk of AD mortality including female gender,African-American race and the administration of cholinesterase inhibitors.Discussion:Our results are consistent with most of the researches.Compared with non-dementia population,patients with AD have a relatively higher risk of mortality,especially those aged 65-74,whose mortality risk is almost 8.5 times that of non-dementia population.Therefore,we should pay enough attention to AD mortality.There are many factors that predict the risk of AD mortality.Some of them,such as age,gender and race are difficult to intervene,however,they are of great value to evaluate the mortality risk of AD patients.These uncontrollable factors can not only influence the mortality risk of AD patients through genes,but also indirectly through comorbidities,complications,administration of medications,social support and living environment.What’s more,although there are intricate links between some comorbidities,complications and administration of medications,they can be intervened and controlled,and among them,diabetes can not only affect the risk of AD mortality independently,but also affect the prognosis of AD patients through other comorbidities.On the other hand,the occurrence of complications,such as hallucination,depression and delirium may indicate the aggravation of AD pathology,the deterioration of the disease,and the decline of the patient’s cognition and dependence,which predicting a poorer prognosis.Clinical application of cholinesterase inhibitors or vitamin E may improve the prognosis of AD patients.Conclusion:Factors such as age,gender and race,are difficult to be altered,but they can predict the risk of AD mortality and provide a strategy for doctors to slow down the disease deterioration in the early stage of the disease,when patients subject to little comorbidities and complications.On the other hand,in the late stage of the disease,we may be able to reduce the risk of AD mortality by the control of comorbidities and complications as well as the administration of medications,which will prolong survive time of AD patients.