Novel diagnostic tool PLUS accurate for detecting acute pneumonia in elderly adults

A novel diagnostic tool, called the Pneumonia Lung Ultrasound Score (PLUS), is an easy, biomarker-derived, and accurate method for detecting acute pneumonia in the very old, a recent study has found.

Researchers conducted a prospective, single-centre cohort analysis of 132 elderly adults (mean age, 85.3±6.9 years; 69 percent female) who underwent chest X rays (CXR) and lung ultrasound (LUS). PLUS was defined as LUS with biomarkers such as the brain natriuretic peptide (BNP), high-sensitivity C-reactive protein (hs-CRP), and partial pressure arterial oxygen/fraction of inspired oxygen ratio (PaO₂/FIO₂).

LUS emerged as a better diagnostic tool than CXR, particularly in patients with multidimensional prognostic index (MPI) scores 0.33–0.66 (diagnostic accuracy, 0.97 vs 0.72; p=0.04) and >0.66 (diagnostic accuracy, 1.00 vs 0.64; p=0.003). MPI is an indicator of short- and long-term mortality, as well as of frailty.

In turn, PLUS was significantly superior in detecting acute pneumonia relative to LUS (area under the curve [AUC], 0.92 vs 0.86; p=0.029) and CXR (AUC, 0.92 vs 0.67; p<0.0001). Removing BNP from the PLUS model slightly weakened its diagnostic value, though it remained significantly better than LUS (AUC, 0.91; p=0.039 vs LUS).

In the PLUS scheme, each 100-unit drop in PaO₂/FIO₂ was worth one point, as was each 10-ng/mL increase in hs-CRP. An increase in BNP of 500 pg/mL was worth –0.5 points. The risk of pneumonia increased by a factor of two with every 1-unit increase in the PLUS score (odds ratio, 2.26, 95 percent confidence interval, 1.71–2.99).