Radiographic resolution of community-acquired bacterial pneumonia in the elderly.

OBJECTIVES: To investigate the radiographic clearance of proven community-acquired nontuberculous bacterial pneumonia in nonimmunocompromised older patients to provide working estimates of the rate of radiographic resolution as a function of the patient cumulative comorbidities, extent of initial radiographic involvement, functional status, and causative pathogens.
DESIGN: A prospective study. PARTICIPANTS: Seventy-four patients aged 70 and older, consecutively admitted to a hospital for community-acquired bacterial pneumonia.
SETTING: A university-affiliated teaching hospital. MEASUREMENTS: Chest radiographs were performed every 3 weeks from the date of admission for a total period of 12 weeks or until all radiographic abnormalities had resolved or returned to baseline.
RESULTS: Sixty-four patients (86%) completed the study. The rate of radiographic clearance was estimated at 35.1% within 3 weeks, 60.2% within 6 weeks, and 84.2% within 12 weeks. Radiographic resolution was significantly slower for those with high comorbidity index, bacteremia, multilobar involvement, and enteric gram-negative bacilli pneumonias. Multivariate regression analysis demonstrated that the comorbidity index (relative risk for clearance=0.67 per class index, P<.001) and multilobar disease (relative risk for clearance=0.24 for more than one lobe, P<.001) had independent predictive value (Cox proportional hazards regression model) on the rate of resolution.
CONCLUSION: The radiographic resolution of nontuberculous bacterial pneumonia in the elderly should take into account the extent of lobar disease and the burden of underlying illnesses. A waiting period of 12 to 14 weeks is recommended for slowly resolving pneumonia to be considered nonresolving.