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Defining severe community-acquired pneumonia: a significant barrier to improving patient outcomes


Severe community-acquired pneumonia (sCAP) is an exaggerated inflammatory and coagulation response to infection. sCAP has high rates of mortality and necessitates modified treatment to that for mild/moderate community-acquired pneumonia (CAP). Despite the grave nature of this condition it is poorly characterised. A systematic review was performed to gauge current data and identify unmet needs associated with sCAP.


MEDLINE was searched for English-language papers concerning sCAP published after 1998.


There are a number of published indices for diagnosing sCAP but these are difficult to use in the clinical setting. In the literature, sCAP is defined as CAP requiring admittance to an ICU or as CAP that results in death. Current International Statistical Classification of Disease and diagnosis-related group codes do not specify whether pneumonia is community acquired or hospital acquired or indicate the severity of the infection. Estimates of the prevalence of sCAP in patients with CAP range from 6.6 to 16.0% [1, 2]. Mortality rates for patients with sCAP range from 10 to 55% [3, 4]. The discrepancy in these rates emphasises the variation in hospital practices due to the lack of an objective definition of sCAP. The absence of a clear definition for sCAP could result in inappropriate treatment of this life-threatening condition, increasing mortality rates. There are scant data concerning the costs of treating sCAP; increased expenditure for patients with sCAP versus those with CAP results from ICU treatment, increased length of hospital stay, mechanical ventilation, vasopressor use and rehabilitation costs. It is expected that the clinical and cost benefits of new therapies will be more easily recognised if sCAP is consistently defined. Defining sCAP appropriately requires a focused international initiative and collaboration between clinicians and payers.


There is a major unmet need for a meaningful definition of sCAP. Poor characterisation of sCAP has resulted in variable reports of its prevalence and may result in inappropriate treatment leading to increased mortality in this patient population. The results of this systematic review form the basis for developing a new treatment pathway to improve outcomes for patients with sCAP.


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Balp, M., Naujoks, C. Defining severe community-acquired pneumonia: a significant barrier to improving patient outcomes. Crit Care 13 (Suppl 1), P348 (2009).

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  • Inappropriate Treatment
  • Group Code
  • Hospital Practice
  • International Initiative
  • International Statistical Classification