Comorbidities are common in people living with Alzheimer’s disease

Comorbidities are common in people living with AD where chronic comorbidities co-exist, such as diabetes and cardiovascular diseases.^1,8-10Patients with AD are also at risk for the occurrence of acute illnesses, such as infections and fractures.^4,11Apathy, irritability, depression, and agitation are among the most common neuropsychiatric symptoms in AD.^12-14The relationship between comorbidity and AD is multifaceted, and causal relationships are difficult to disentangle.^1,3Several illnesses can be risk factors for AD, such as type 2 diabetes,¹ and having AD increases the comorbidity risk for some acute conditions such as infections and fractures.^2,3,12On the other hand, some diseases may be an early sign of dementia, such as sleep disorders.⁷ Several comorbidities also interact or lead to each other; comorbidity can be an independent risk factor for AD and other AD risk factors.^2,3Overall, there may be bidirectional or multidirectional relationships between AD and comorbidities;^2,3 further investigation is necessary to understand the relationship between comorbidities and AD, including shared risk factors or disease mechanisms.¹

References:
1.Lanctôt KL, Hahn-Pedersen JH, Eichinger CS, et al. Burden of illness in people with Alzheimer’s disease: a systematic review of epidemiology, comorbidities and mortality. J Prev Alzheimers Dis 2023; 1–11.

2.Ramos-Vera C, Saintila J, O’Diana AG, Calizaya-Milla YE. Identifying latent comorbidity patterns in adults with perceived cognitive impairment: network findings from the behavioral risk factor surveillance system. Front Public Health 2022; 10: 981944.

3.Santiago JA, Potashkin JA. The impact of disease comorbidities in Alzheimer’s disease. Front Aging Neurosci 2021; 13: 631770.

4.Janbek J, Frimodt-Møller N, Laursen TM, Waldemar G. Dementia identified as a risk factor for infection-related hospital contacts in a national, population-based and longitudinal matched-cohort study. Nat Aging 2021; 1 (2): 226–233.

5.Sipilä PN, Heikkilä N, Lindbohm JV, et al. Hospital-treated infectious diseases and the risk of dementia: a large, multicohort, observational study with a replication cohort. Lancet Infect Dis 2021; 21 (11): 1557–1567.

6.Muzambi R, Bhaskaran K, Smeeth L, et al. Assessment of common infections and incident dementia using UK primary and secondary care data: a historical cohort study. Lancet Healthy Longev 2021; 2 (7): e426–e435.

7.He C, Hu Z, Jiang C. Sleep disturbance: an early sign of Alzheimer’s disease. Neurosci Bull 2020; 36 (4): 449–451.

8.Beerten SG, Helsen A, De Lepeleire J, et al. Trends in prevalence and incidence of registered dementia and trends in multimorbidity among patients with dementia in general practice in Flanders, Belgium, 2000–2021: a registry-based, retrospective, longitudinal cohort study. BMJ Open 2022; 12 (11): e063891.

9.Clague F, Mercer SW, McLean G, et al. Comorbidity and polypharmacy in people with dementia: insights from a large, population-based cross-sectional analysis of primary care data. Age Ageing 2017; 46 (1): 33–39.

10.Browne J, Edwards DA, Rhodes KM, et al. Association of comorbidity and health service usage among patients with dementia in the UK: a population-based study. BMJ Open 2017; 7 (3): e012546.

11.Jeon JH, Park JH, Oh C, et al. Dementia is associated with an increased risk of hip fractures: a nationwide analysis in Korea. J Clin Neurol 2019; 15 (2): 243–249.

12.Lyketsos CG, Steinberg M, Tschanz JT, et al. Mental and behavioral disturbances in dementia: findings from the Cache County Study on Memory in Aging. Am J Psychiatry 2000; 157 (5): 708–714.