Risk Factors for Pneumonia and Other Lower Respiratory Tract Infections in Elderly Residents of Long-term Care Facilities

BACKGROUND: Little is known about the risk factors, outcome, and impact of pneumonia and other lower respiratory tract infections (LRTIs) in residents of long-term care facilities. OBJECTIVE: To determine the risk factors and the effect of these infections on functional status and clinical course. METHODS: Active surveillance for these infections was conducted for 475 residents in 5 nursing homes from July 1, 1993, through June 30, 1996. Information regarding potential risk factors for these infections, functional status, transfers to hospital, and death was also obtained. RESULTS: Two hundred seventy-two episodes of pneumonia and other LRTIs occurred in 170 residents during 228 757 days of surveillance for an incidence of 1.2 episodes per 1000 resident-days. Multivariable analysis revealed that older age (odds ratio OR, 1.7; 95% confidence interval CI, 1.1-2.6 per 10-year interval; P = .01), male sex (OR, 1.9; 95% CI, 1.1-3.5; P = .03), swallowing difficulty (OR, 2.0; 95% CI, 1.2-3.3; P = .01), and the inability to take oral medications (OR, 8.3; 95% CI, 1.4-50.3; P = .02) were significant risk factors for pneumonia; receipt of influenza vaccine (OR, 0.4; 95% CI, 0.3-0.5; P = .01) was protective. Age (OR, 1.6 95% CI, 1.0-2.5 per 10-year interval; P = .05) and immobility (OR, 2.6; 95% CI, 1.8-3.8; P = .01) were significant risk factors for other LRTIs, and influenza vaccination was protective (OR, 0.3; 95% CI, 0.2-0.4; P = .01). Residents with pneumonia (OR, 0.7; 95% CI, 0.3-1.4; P = .31) or with other LRTIs (OR, 0.5; 95% CI, 0.2-1.1; P = .43) were no more likely to have a deterioration in functional status than individuals in whom infection did not develop. CONCLUSIONS: Swallowing difficulty and lack of influenza vaccination are important, modifiable risks for pneumonia and other LRTIs in elderly residents of long-term care facilities. Our findings challenge the commonly held belief that pneumonia leads to long-term decline in functional status in this population.