For patients admitted to hospital, mortality rate ranges from 5% to 15%, but increases to 20% to 50% in patients requiring admission to the intensive care unit (ICU).[6]Torres A, Peetermans WE, Viegi G, et al. Risk factors for community-acquired pneumonia in adults in Europe: a literature review. Thorax. 2013 Nov;68(11):1057-65.
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[118]Luna HI, Pankey G. The utility of blood culture in patients with community-acquired pneumonia. Ochsner J. 2001 Apr;3(2):85-93.
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Patients treated in the community generally have a good prognosis.[1]Lim WS, Baudouin SV, George RC, et al; Pneumonia Guidelines Committee of the BTS Standards of Care Committee. British Thoracic Society guidelines for the management of community acquired pneumonia in adults: update 2009. Thorax. 2009 Oct;64(suppl 3):iii1-55.
https://thorax.bmj.com/content/64/Suppl_3/iii1.long
http://www.ncbi.nlm.nih.gov/pubmed/19783532?tool=bestpractice.com
Risk factors associated with increased 30-day mortality include bacteraemia, admission to the ICU, comorbidities (especially neurological disease), and infection with a potentially multidrug-resistant pathogen (e.g., Staphylococcus aureus, Pseudomonas aeruginosa, Enterobacteriaceae).[34]Cillóniz C, Polverino E, Ewig S, et al. Impact of age and comorbidity on cause and outcome in community-acquired pneumonia. Chest. 2013 Sep;144(3):999-1007.
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[143]Torres A, Cillóniz C, Ferrer M, et al. Bacteraemia and antibiotic-resistant pathogens in community acquired pneumonia: risk and prognosis. Eur Respir J. 2015 May;45(5):1353-63.
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[144]Sligl WI, Marrie TJ. Severe community-acquired pneumonia. Crit Care Clin. 2013 Jul;29(3):563-601.
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[145]Melzer M, Welch C. 30-day mortality in UK patients with bacteraemic community-acquired pneumonia. Infection. 2013 Oct;41(5):1005-11.
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Readmission rates in patients with CAP range from 7% to 12%.[160]Jasti H, Mortensen EM, Obrosky DS, et al. Causes and risk factors for rehospitalization of patients hospitalized with community-acquired pneumonia. Clin Infect Dis. 2008 Feb 15;46(4):550-6.
http://cid.oxfordjournals.org/content/46/4/550.full
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[161]Capelastegui A, España Yandiola PP, Quintana JM, et al. Predictors of short-term rehospitalization following discharge of patients hospitalized with community-acquired pneumonia. Chest. 2009 Oct;136(4):1079-85.
http://www.ncbi.nlm.nih.gov/pubmed/19395580?tool=bestpractice.com
In most cases, exacerbation of comorbidities (mainly cardiovascular, pulmonary, or neurological disease) is responsible for readmission.
Prognostic biomarkers such as pro-adrenomedullin, prohormone forms of atrial natriuretic peptide, cortisol, procalcitonin, and C-reactive protein are being studied as predictors of mortality; however, further studies are required before these biomarkers are used for this function in clinical practice.[162]Viasus D, Del Rio-Pertuz G, Simonetti AF, et al. Biomarkers for predicting short-term mortality in community-acquired pneumonia: a systematic review and meta-analysis. J Infect. 2016 Mar;72(3):273-82.
http://www.ncbi.nlm.nih.gov/pubmed/26777314?tool=bestpractice.com