Guo et al. Respiratory Research (2019) 20:22 https://doi.org/10.1186/s12931-019-0991-4 RESEARCH Open Access Scored minor criteria for severe community-acquired pneumonia predicted better Qi Guo1,2*† , Wei-dong Song1†, Hai-yan Li3†, Yi-ping Zhou2, Ming Li2, Xiao-ke Chen2, Hui Liu2, Hong-lin Peng2, Hai-qiong Yu2, Xia Chen2, Nian Liu2, Zhong-dong Lü1, Li-hua Liang4, Qing-zhou Zhao4 and Mei Jiang5 Abstract Background: Infectious Disease Society of America/American Thoracic Society (IDSA/ATS) minor criteria for severe community-acquired pneumonia (CAP) are of unequal weight in predicting mortality, but the major problem associated with IDSA/ATS minor criteria might be a lack of consideration of weight in prediction in clinical practice. Would awarding different points to the presences of the minor criteria improve the accuracy of the scoring system? It is warranted to explore this intriguing hypothesis. Methods: A total of 1230 CAP patients were recruited to a retrospective cohort study. This was tested against a prospective two-center cohort of 1749 adults with CAP. 2 points were assigned for the presence of PaO2/FiO2 ≤ 250 mmHg, confusion, or uremia on admission and 1 point for each of the others. Results: The mortality rates, and sequential organ failure assessment (SOFA) and pneumonia severity index (PSI) scores increased significantly with the numbers of IDSA/ATS minor criteria present and minor criteria scores. The correlations of the minor criteria scores with the mortality rates were higher than those of the numbers of IDSA/ATS minor criteria present. As were the correlations of the minor criteria scores with SOFA and PSI scores, compared with the numbers of IDSA/ATS minor criteria present. The pattern of sensitivity, specificity, positive predictive value, and Youden’sindexof scored minor criteria of ≥2 scores or the presence of 2 or more IDSA/ATS minor criteria for prediction of mortality was the best in the retrospective cohort, and the former was better than the latter. The validation cohort confirmed a similar pattern. The area under the receiver operating characteristic curve of scored minor criteria was higher than that of IDSA/ATS minor criteria in the retrospective cohort, implying higher accuracy of scored version for predicting mortality. The validation cohort confirmed a similar paradigm. Conclusions: Scored minor criteria orchestrated improvements in predicting mortality and severity in patients with CAP, and scored minor criteria of ≥2 scores or the presence of 2 or more IDSA/ATS minor criteria might be more valuable cut-off value for severe CAP, which might have implications for more accurate clinical triage decisions. Keywords: Community-acquired pneumonia, Minor criteria, Score, Mortality, Severity * Correspondence: [email protected] †Qi Guo, Wei-dong Song and Hai-yan Li contributed equally to this work. 1Department of Respiratory Medicine, Shenzhen Hospital, Peking University, Lianhua road No. 1120, Shenzhen 518036, Guangdong, China 2Department of Respiratory Medicine, The Eighth Affiliated Hospital (Shenzhen Futian), Sun Yat-sen University, Shenzhen 518033, Guangdong, China Full list of author information is available at the end of the article © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Guo et al. Respiratory Research (2019) 20:22 Page 2 of 10 Background chest discomfort or dyspnoea [8]. Patients who were Community-acquired pneumonia (CAP) is the most younger than 18 years, who had been hospitalized during common cause of mortality from infectious diseases and the 28 days preceding the study, who had severe im- a big burden to finite hospital and intensive care unit munosuppression, active tuberculosis, or end-stage dis- (ICU) resources [1]. Significant improvements in treat- eases, who had a written “do not resuscitate” order, or ment of CAP have been emerging, but mortality remains whose baseline consciousness was unclear, which was unacceptably high [2, 3]. In 2007, the Infectious Disease not derived from pneumonia, were excluded. Society of America and the American Thoracic Society (IDSA/ATS) designed minor criteria with the aim to Clinical management guide ICU admission, not to predict mortality [2]. We Patients with CAP were admitted and attended by re- [4] and Sibila et al. [5] have reported that some of these spiratory physicians based on the ATS guidelines [2, 12] criteria might be predictors of mortality, while others and the Surviving Sepsis Campaign guidelines [13, 14]. not. The minor criteria are of unequal weight in predict- The initial antibiotic regimens were consistent with the ing mortality and some of these criteria could be guidelines on the management of CAP, in addition to removed to orchestrate a simplified version [4, 6–10]. subsequently cultured pathogens. Therefore, all patients Therefore, the major problem associated with IDSA/ were regarded as receiving adequate antibiotics and were ATS minor criteria might be a lack of consideration of discharged home when they reached clinical stability weight in prediction in clinical practice. and became afebrile. We found that mortality among patients with severe CAP depended on combinations of IDSA/ATS minor Score assigned for each of IDSA/ATS minor criteria criteria and the combination of arterial oxygen pressure/ On the basis of the weight of IDSA/ATS minor criteria fraction inspired oxygen (PaO2/FiO2) ≤ 250 mmHg, con- for severe CAP in predicting mortality, two points were fusion and uremia predicted higher mortality [11]. PaO2/ assigned for the presence of PaO2/FiO2 ≤ 250 mmHg, FiO2 ≤ 250 mmHg, confusion and uremia had the stron- confusion, or uremia on admission to the hospitals and gest association with mortality based on what we [4, 11], one point for each of the others in scored minor criteria Brown et al., [6] Liapikou et al., [7] and Phua et al. [8] scoring system (Table 1). reported. Consequently, would awarding 2 points to the presence of PaO2/FiO2 ≤ 250 mmHg, confusion or Outcome uremia improve the accuracy of the scoring system? The The main outcome measure was 28-day mortality. Sec- more accurate the scoring system, the higher the patient ondary outcomes incorporated sequential organ failure survival. Hence, it is worthwhile to explore this intri- assessment (SOFA) and pneumonia severity index (PSI) guing hypothesis. scores at 72 h after commencing therapy. Two cohort studies were conducted to derive and validate a scored minor criteria . Data collection A total of 1245 patients were enrolled consecutively and Materials and methods 15 cases were excluded from the retrospective cohort Design and setting due to exclusion criteria (2 patients younger than 18 A retrospective cohort study of 1245 adult patients with CAP was conducted at the Department of Respiratory Table 1 The minor criteria scoring systems Medicine in a Chinese affiliated tertiary hospital of a Weight Variable IDSA/ATS Scored medical university from 2005 to 2009. We performed a minor criteria minor criteria ≥ prospective two-centre cohort study of 1779 consecutive Respiratory rate 30 breaths/min 1 1 ≤ adult patients with CAP between 2010 and 2014 at the PaO2/FiO2 250 mmHg 1 2 Departments of Respiratory Medicine in two Chinese af- Multilobar infiltrates 1 1 filiated tertiary hospitals of two medical universities, one Confusion 1 2 of which was the same hospital in the retrospective co- Uremia 1 2 hort study. Leukopenia 1 1 Criteria for enrollment Thrombocytopenia 1 1 CAP was defined as an acute infection of the pulmonary Hypothermia 1 1 parenchyma associated with an acute infiltrate on the Hypotension 1 1 chest radiograph with two or more symptoms including Total 9 variables 12 scores fever (> 38 °C), hypothermia (< 36 °C), rigors, sweats, NOTE: IDSA/ATS: The Infectious Disease Society of America and the American new cough or change in color of respiratory secretions, Thoracic Society. PaO2/FiO2: Arterial oxygen pressure/fraction inspired oxygen Guo et al. Respiratory Research (2019) 20:22 Page 3 of 10 years, 1 patient hospitalized during the 28 days preced- mean ± standard deviation (SD), respectively. Chi-Square ing the study, 6 patients with severe immunosuppres- test, one-way ANOVA, and Spearman rank correlation sion, 2 patients with active tuberculosis, 2 patients with were employed. The receiver operating characteristic end-stage diseases, 1 patient with a written “do not re- (ROC) curves were created and the areas under the curves suscitate” order, and 1 patient with unclear baseline con- (AUCs) were calculated to illustrate and compare the ac- sciousness). 30 cases were excluded from 1779 curacy of the indices. The sensitivities, specificities, posi- consecutive patients in the validation cohort (3 patients tive predictive values (PPVs), negative predictive values younger than 18 years, 4 patients hospitalized during the (NPVs), and Youden’s indices were also calculated. A p 28 days preceding the study, 9 patients with severe im- value of < 0.05 was considered statistically significant. munosuppression, 2 patients with active tuberculosis, 5 patients with end-stage diseases, 4 patients with a writ- Results ten “do not resuscitate” order, and 3 patients with un- Baseline characteristics of study cohorts clear baseline consciousness) (Fig. 1). All the patients The baseline characteristics of the patients were summa- had chest radiographys and computer tomography (CT) rized in Table 2. The IDSA/ATS minor criteria present scans. The frontal and lateral chest radiographic findings in the prospective cohort were observed more fre- and CT scan images were classified independently by quently than those in the retrospective cohort and two senior radiologists (LH Liang and QZ Zhao).