1.File TM, Jr., Marrie TJ. Burden of community-acquired pneumonia in North American adults. Postgraduate medicine.2010;122:130–41.
2.Fine MJ, Smith MA, Carson CA, Mutha SS, Sankey SS, Weissfeld LA, Kapoor WN. Prognosis and outcomes of patients with community-acquired pneumonia. Ameta-analysis. JAMA. 1996;275:134–41.
3.Morimoto K, Suzuki M, Ishifuji T, Yaegashi M, Asoh N, Hamashige N, Abe M,Aoshima M, Ariyoshi K; Adult Pneumonia Study Group-Japan (APSG-J). The burden andetiology of community-onset pneumonia in the aging Japanese population: amulticenter prospective study. PLoS One. 2015;10:e0122247.
4.Yurkovich M, Avina-Zubieta JA, Thomas J, Gorenchtein M, Lacaille D. A systematic review identifies valid comorbidity indices derived from administrative health data. Journal of clinical epidemiology.2015;68:3–14.
5.Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. Journal of chronic diseases.1987;40:373–83.
6.Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index for use with ICD–9-CM administrative databases. Journal of clinical epidemiology. 1992;45:613–19.
7.Romano PS, Roos LL, Jollis JG. Adapting a clinical comorbidity index for use with ICD–9-CM administrative data: differing perspectives. Journal of clinical epidemiology.1993;46:1075–1079; discussion 1081–90.
8.D’Hoore W, Bouckaert A, Tilquin C. Practical considerations on the use of the Charlson comorbidity index with administrative data bases. Journal of clinical epidemiology. 1996;49:1429–33.
9.Quan H, Sundararajan V, Halfon P, Fong A, Burnand B, Luthi JC, Saunders LD,Beck CA, Feasby TE, Ghali WA. Coding algorithms for defining comorbidities in ICD–9-CM and ICD–10 administrative data. Med Care. 2005;43:1130–9.
10.Quan H, Li B, Couris CM, Fushimi K, Graham P, Hider P, Januel JM, SundararajanV. Updating and validating the Charlson comorbidity index and score for riskadjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol. 2011;173:676–82.
11.Health and Global Policy Institute. Payment System. Japan Health Policy NOW 2016; http://japanhpn.org/en/finan2/. Accessed September 10, 2019.
12.World Health Organization. ICD–10 Version: 2016. 2016; http://apps.who.int/classifications/icd10/browse/2016/en#/I48. Accessed September 10, 2019.
13.Miyashita N, Matsushima T, Oka M, Japanese Respiratory S. The JRS guidelines for the management of community-acquired pneumonia in adults: an update and new recommendations. Internal medicine (Tokyo, Japan). 2006;45:419–28.
14. Neill AM, Martin IR, Weir R, Anderson R, Chereshsky A, Epton MJ, Jackson R,Schousboe M, Frampton C, Hutton S, Chambers ST, Town GI. Community acquiredpneumonia: aetiology and usefulness of severity criteria on admission. Thorax.1996;51:1010–6.
15.Franzen D, Lim M, Bratton DJ, Kuster SP, Kohler M. The Roles of the Charlson Comorbidity Index and Time to First Antibiotic Dose as Predictors of Outcome in Pneumococcal Community-Acquired Pneumonia. Lung. 2016;194:769–75.
16.Torres OH, Muñoz J, Ruiz D, Ris J, Gich I, Coma E, Gurguí M, Vázquez G.Outcome predictors of pneumonia in elderly patients: importance of functionalassessment. J Am Geriatr Soc. 2004;52:1603–9.
17.Matsunuma R, Asai N, Ohkuni Y, Nakashima K, Iwasaki T, Misawa M, Norihiro K.I-ROAD could be efficient in predicting severity of community-acquired pneumonia or healthcare-associated pneumonia. Singapore Med J. 2014;55:318–24.
18.Tashiro M, Fushimi K, Takazono T, Kurihara S, Miyazaki T, Tsukamoto M,Yanagihara K, Mukae H, Tashiro T, Kohno S, Izumikawa K. A mortality predictionrule for non-elderly patients with community-acquired pneumonia. BMC Pulm Med. 2016;16:39.
19.Ogasawara T, Umezawa H, Naito Y, Takeuchi T, Kato S, Yano T, Kasamatsu N,Hashizume I. Procalcitonin-guided antibiotic therapy in aspiration pneumonia and an assessment of the continuation of oral intake. Respir Investig. 2014;52:107–13.