Older patients with dementia at increased risk for flu mortality

BOSTON,27 oct 2009—An epidemiological study on pneumonia and influenza (P&I) in adults age 65 and over reports that patients with dementia are diagnosed with flu less frequently, have shorter hospital stays, and have a fifty percent higher rate of death than those without dementia. The three-pronged study, which analyzed geographic and demographic patterns of P&I and the relationship between P&I and health care accessibility, was published online in advance of print in Journal of the American Geriatrics Society.

"The increased mortality of older patients with dementia hospitalized for flu may be indicative of inadequacies in health care quality and accessibility. It could be beneficial to refine guidelines for the immunization, testing, and treatment of flu in older patients with dementia when planning for the possibility of a flu pandemic," said first and senior author Elena Naumova, PhD, professor of public health and community medicine at Tufts University School of Medicine.

Dementia, defined by the authors as cognitive impairment to the extent that normal activity is impaired, causes unique obstacles to the early diagnosis and treatment of flu. Patients may have difficulty communicating symptoms and medical complications due to poor oral hygiene or impaired swallowing. Additionally, the authors believe that limited access to health care services and inadequate testing practices may contribute to the higher rates of mortality and lower rates of diagnosis of flu seen in older patients with dementia. A geographic analysis of the data showed that P&I rates were highest among older adults in poor and rural areas, where there is a lower concentration of health care facilities.

"Limited access to specialized health care services can delay diagnosis and treatment of the flu, causing it to progress to pneumonia, the fifth leading cause of death among the elderly. This study has helped us identify this vulnerable population, and now further study is needed to confirm the findings and assess the testing and vaccination policies for older patients with dementia," said Naumova.

Study data were obtained from the Centers for Medicaid and Medicare Services (CMS), and covered a span of five years, from 1998 to 2002. Of the 36 million hospitalization records for adults aged 65 and older, more than six million records documented a P&I diagnosis. Of these records showing a P&I diagnosis, over 800,000 (13%) also showed dementia. The demographic and geographic patterns of P&I hospitalizations and their links with hospital accessibility were explored. Pneumonia and influenza admissions, length of stay in a hospital, and mortality rates among elderly with dementia were compared to national estimates.

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Elena Naumova is the director of the Tufts University Initiative for the Forecasting and Modeling of Infectious Diseases (Tufts InForMID), which works to improve biomedical research by developing computational tools in order to assist life science researchers, public health professionals, and policy makers. The center is focused on developing methodology for analysis of large databases to enhance disease surveillance, exposure assessment, and studies of aging.

Co-authors include Sara M. Parisi and Julia Wenger, now graduates of the Master of Public Health program at Tufts University School of Medicine; Denise Castronovo, MS, Mapping Sustainability, LLC; Manisha Pandita, former research assistant in the department of public health and community medicine at Tufts University School of Medicine; and Paula Minihan, PhD, assistant professor of public health and community medicine, Tufts University School of Medicine.

This study was funded by the National Institute of Allergy and Infectious Diseases and the National Institute of Environmental Health Sciences, both part of the National Institutes of Health.