Modifiable risk factors for nursing home-acquired pneumonia

This study sought to identify modifiable risk factors for pneumonia in elderly nursing home residents.

A cohort of 613 elderly residents (age, >65 years) of 5 nursing homes in the New Haven, Connecticut, area was followed-up prospectively from February 2001 through March 2003. The primary outcome was radiographically documented pneumonia within a 12-month surveillance period. Baseline modifiable risk factors were evaluated for their independent association with pneumonia.

Of 613 elderly nursing home residents, 131 (21%) died, and an additional 112 (18%) developed a radiographically documented case of pneumonia during the 12-month surveillance period. Among the 9 candidate modifiable risk factors that were evaluated individually in Cox proportional hazards models adjusting for covariates (i.e., nursing home facility, age, race, coexisting conditions, and immobility), inadequate oral care (hazard ratio [HR], 1.60; 95% confidence interval [CI], 1.06-2.35; P=.024) and swallowing difficulty (HR, 1.65; 95% CI, 1.04-2.62; P=.033) were associated with pneumonia. When modifiable risk factors were evaluated simultaneously in the same Cox proportional hazards model, inadequate oral care (HR, 1.55; 95% CI, 1.04-2.30; P=.030) and swallowing difficulty (HR, 1.61; 95% CI, 1.02-2.55; P=.043) remained independently associated with pneumonia, adjusting for the same covariates. Calculation of population-based attributable fractions showed that 21% of all cases of pneumonia in our cohort could have been avoided if inadequate oral care and swallowing difficulty were not present.

Two biologically plausible and modifiable risk factors increased the risk of pneumonia in elderly nursing home residents. These results provide a framework for the development and testing of a targeted pneumonia prevention strategy.