Background: Our aim was to compare the accuracy of lung ultrasound (LUS) and standard chest x-ray (CXR) for diagnosing pneumonia in older patients with acute respiratory symptoms (dyspnea, cough, hemoptysis, and atypical chest pain) admitted to an acute-care geriatric ward.
Methods: We enrolled 169 (80 M, 89 F) multimorbid patients aged 83.0 ± 9.2 years from January 1 to October 31, 2015. Each participant underwent CXR and bedside LUS within 6 hours from ward admission. LUS was performed by skilled clinicians, blinded to CXR results and clinical history. The final diagnosis (pneumonia vs no-pneumonia) was established by another clinician reviewing clinical and laboratory data independent of LUS results and possibly prescribing chest contrast-enhanced CT. Diagnostic parameters of CXR and LUS were compared with McNemar test on the whole cohort and after stratification for Rockwood Clinical Frailty Scale.
Results: Diagnostic accuracy for pneumonia (96 patients) was significantly higher in LUS (0.90, 95% confidence interval [CI] 0.83-0.96) compared with CXR (0.67, 95%CI 0.60-0.74, P < 0.001). LUS had a better sensitivity (0.92, 95%CI 0.86-0.97 vs 0.47, 95%CI 0.37-0.57) and negative predictive value (0.95, 95% CI 0.83-0.96 vs 0.57, 95%CI 0.48-0.56). In those patients with frailty (n = 87 with Rockwood Clinical Frailty Scale ≥5), LUS maintained a high diagnostic accuracy, but CXR did not (P = 0.0003). Interobserver agreement for LUS, calculated in a subsample of 29 patients, was high (k = 0.90).
Conclusions: In multimorbid patients admitted to an acute geriatric ward, LUS was more accurate than CXR for the diagnosis of pneumonia, particularly in those with frailty. A wider use of LUS should be implemented in this setting.