Lalit Kalra1, Craig J Smith2, John Hodsoll3, Andy Vail4, Saddif Irshad1, Dulka Manawadu5. 1. 1 Department of Basic and Clinical Neurosciences, Institute of Psychiatry, Psychology and Neurosciences, King's College London, London, UK. 2. 2 Greater Manchester Comprehensive Stroke Centre and Division of Cardiovascular Sciences, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Trust, Salford, UK. 3. 3 Biostatistics Department, NIHR Biomedical Research Centre for Mental Health and Institute of Psychiatry, Psychology and Neurosciences, King's College London, London, UK. 4. 4 Centre for Biostatistics, University of Manchester, Manchester, UK. 5. 5 Department of Clinical Neurosciences, King's College Hospital NHS Foundation Trust, London, UK.
Abstract
BACKGROUND AND AIM: Pyrexia-dependent clinical algorithms may under or overdiagnose stroke-associated pneumonia. This study investigates whether inclusion of elevated C-reactive protein as a criterion improves diagnosis. METHODS: The contribution of C-reactive protein ≥30 mg/l as an additional criterion to a Centers for Disease Control and Prevention-based algorithm incorporating pyrexia with chest signs and leukocytosis and/or chest infiltrates to diagnose stroke-associated pneumonia was assessed in 1088 acute stroke patients from 37 UK stroke units. The sensitivity, specificity, and positive predictive value of different approaches were assessed using adjudicated stroke-associated pneumonia as the reference standard. RESULTS: Adding elevated C-reactive protein to all algorithm criteria did not increase diagnostic accuracy compared with the algorithm alone against adjudicated stroke-associated pneumonia (sensitivity 0.74 (95% CI 0.65-0.81) versus 0.72 (95% CI 0.64-0.80), specificity 0.97 (95% CI 0.96-0.98) for both; kappa 0.70 (95% CI 0.63-0.77) for both). In afebrile patients (n = 965), elevated C-reactive protein with chest and laboratory findings had sensitivity of 0.84 (95% CI 0.67-0.93), specificity of 0.99 (95% CI 0.98-1.00), and kappa 0.80 (95% CI 0.70-0.90). The modified algorithm of pyrexia or elevated C-reactive protein and chest signs with infiltrates or leukocytosis had sensitivity of 0.94 (95% CI 0.87-0.97), specificity of 0.96 (95% CI 0.94-0.97), and kappa of 0.88 (95% CI 0.84-0.93) against adjudicated stroke-associated pneumonia. CONCLUSIONS: An algorithm consisting of pyrexia or C-reactive protein ≥30 mg/l, positive chest signs, leukocytosis, and/or chest infiltrates has high accuracy and can be used to standardize stroke-associated pneumonia diagnosis in clinical or research settings. TRIAL REGISTRATION: http://www.isrctn.com/ISRCTN37118456.
BACKGROUND AND AIM: Pyrexia-dependent clinical algorithms may under or overdiagnose stroke-associated pneumonia. This study investigates whether inclusion of elevated C-reactive protein as a criterion improves diagnosis. METHODS: The contribution of C-reactive protein ≥30 mg/l as an additional criterion to a Centers for Disease Control and Prevention-based algorithm incorporating pyrexia with chest signs and leukocytosis and/or chest infiltrates to diagnose stroke-associated pneumonia was assessed in 1088 acute stroke patients from 37 UK stroke units. The sensitivity, specificity, and positive predictive value of different approaches were assessed using adjudicated stroke-associated pneumonia as the reference standard. RESULTS: Adding elevated C-reactive protein to all algorithm criteria did not increase diagnostic accuracy compared with the algorithm alone against adjudicated stroke-associated pneumonia (sensitivity 0.74 (95% CI 0.65-0.81) versus 0.72 (95% CI 0.64-0.80), specificity 0.97 (95% CI 0.96-0.98) for both; kappa 0.70 (95% CI 0.63-0.77) for both). In afebrile patients (n = 965), elevated C-reactive protein with chest and laboratory findings had sensitivity of 0.84 (95% CI 0.67-0.93), specificity of 0.99 (95% CI 0.98-1.00), and kappa 0.80 (95% CI 0.70-0.90). The modified algorithm of pyrexia or elevated C-reactive protein and chest signs with infiltrates or leukocytosis had sensitivity of 0.94 (95% CI 0.87-0.97), specificity of 0.96 (95% CI 0.94-0.97), and kappa of 0.88 (95% CI 0.84-0.93) against adjudicated stroke-associated pneumonia. CONCLUSIONS: An algorithm consisting of pyrexia or C-reactive protein ≥30 mg/l, positive chest signs, leukocytosis, and/or chest infiltrates has high accuracy and can be used to standardize stroke-associated pneumonia diagnosis in clinical or research settings. TRIAL REGISTRATION: http://www.isrctn.com/ISRCTN37118456.