People with Alzheimer's disease (AD) are more often hospitalized after antibiotic initiation than people without the AD, a new study from the University of Eastern Finland shows. The risk of hospitalization was 40% higher for persons with Alzheimer's disease. 

Out of individual antibiotics, persons with Alzheimer's disease were more often hospitalized than people without AD after the initiation of cephalexin, pivmecillinam, amoxicillin, and doxycycline.

Hospitalization was associated with pre-existing illnesses, such as epilepsy or cancer, and certain medications, such as antipsychotic and benzodiazepine use. This study used data from a Finnish register-based cohort, which includes all persons diagnosed with Alzheimer's disease in Finland during 2005–2011.

The researchers analyzed 34,785 persons who used antibiotics in an outpatient setting after their Alzheimer's disease diagnosis and their comparison persons matched according to age, sex, and region of residence.

Previous studies have shown that infections are a significant cause of hospitalization in persons with dementia. This study is the first to document hospitalization after antibiotic initiation. These results confirm the role of infections as a cause of hospitalization in persons with Alzheimer's disease.

Among oral antibiotic initiators, persons with AD were more likely hospitalized than persons without the AD. In both groups, comorbidities like diabetes, rheumatoid arthritis, and epilepsy and use of antipsychotics, benzodiazepines, and oral glucocorticoids were associated with an increased risk of hospitalization.

Further research is needed to find practices to prevent infections in older persons and especially in persons with cognitive disorders and so reduce the need for infection-related hospitalization.

Infections are a common precipitating factor for delirium in older persons, and cognitive disorders are a well-known predisposing factor for delirium. Especially, UTI is a risk factor for delirium in persons with the AD.

Adverse symptoms

Infections may cause other adverse symptoms like dehydration and falls associated with hospitalization. Also, persons with cognitive impairment and dementia are at a higher risk of falls.

The use of benzodiazepines, antipsychotics, and antidementia drugs are known to be a risk factor for pneumonia and hospitalization. Also, psychotropic drug use is also known to be a risk factor for falls. During infection, persons with cognitive impairment need comprehensive good care to avoid injurious falls and other adverse events like delirium.