Use of diagnostic tests for presumed lower respiratory tract infection in long-term care facilities

To describe the current use of diagnostic tests for management of presumed lower respiratory tract infection in selected long-term care facilities (LTCFs) in Canada and to correlate test use with facility and resident characteristics.

Prospective, 12-month multicenter cohort study.

A convenience sample of 21 LTCFs in Canada.

LTCF residents prescribed antimicrobial therapy for presumed lower respiratory tract infection.

Data collection included facility characteristics, patient demographics, level of care, comorbidities, clinical presentations, diagnostic testing, and outcomes. Diagnostic test use was correlated with facility access and resident and episode characteristics.

Forty-two percent of 1,702 episodes had chest radiography obtained, 28.5% had pulse oximetry, 23.8% had peripheral leukocyte count, and 3.3% had sputum culture. On-site access correlated with obtaining chest radiography (odds ratio (OR)=4.4; 95% confidence interval (CI)=3.2-6.0) and oximetry (OR=30.3; 95% CI=16.4-55.8). Analyses stratified according to facility found that greater test use was associated with greater premorbid functional impairment and more-severe presentations. Advance directives, time to stabilization, and mortality did not correlate with test use. In multivariate analysis, significant variability between facilities for chest radiography and oximetry remained after incorporating differences in access to diagnostic testing and other facility or resident variables.

The use of diagnostic tests in the management of presumed lower respiratory tract infection in these Canadian LTCFs is highly variable. Access to diagnostic tests and severity of presentations correlate with test use but do not fully explain the variability in use in institutions.