Pneumonia and Influenza hospitalizations in people age 65 and older with cognitive impairment

Pneumonia and influenza (P&I), the fifth leading cause of death in elderly (people age 65 and older), is more prevalent in nursing homes residents and is an important cause of death for those suffering from dementia or other cognitive impairments (CI). This study explores the degree of P&I complications in the US elderly with CI. All P&I hospitalization records for a 5-year period (1998-2002) were abstracted from the Centers for Medicare and Medicaid Services database. Of the 6,371,878 records of P&I, almost 30% of records had an indication of potential cognitive impairment (defined as ICD9M 290-359). Indication of CI occurred in diagnosis codes, which are typically reserved for co-morbidity. During the study period, 26,779 patients with CI were hospitalized due to influenza, of which 3,872 had a diagnosis of Alzheimers - the most prevalent form of CI among people age 65 and above. The analysis indicates that influenza was less frequently diagnosed in Alzheimer's patients: only 1.2% of Alzheimer's patients were diagnosed with influenza compared to estimated national average of 1.6%. Furthermore, patients with Alzheimer's disease had higher mortality, 6.03% expired in the hospital (males: 7.7% and females: 5.1%) compared to estimated national average of 4.06% for both genders. Duration of hospitalizations due to influenza was longer among Alzheimer's patients (median=5days, mean [SD] =5.9[4.7]days, n=3,124) than nationwide estimates (median=4days, mean[SD]=5.6[5.1]days, n=81,414). These preliminary results support our hypothesis that elderly with CI are at elevated risk for influenza complications and are in need of special care during influenza epidemics.