Importance of severity of illness assessment in management of lower respiratory infections

Defining severe pneumonia

Pneumonia is an important clinical and public health problem. Identification and prediction of severe pneumonia are significant concerns. Attempts to define severe pneumonia should recognize that different purposes are served by different definitions; no single definition meets all needs. At present, several prediction models have been proposed or validated. Biomarkers are not yet ready for routine use. The authors recommend careful consideration of the implications of any given definition of pneumonia severity. Outcome studies are needed to integrate human and health care system factors with the application of pneumonia severity definitions.

Severity of illness scoring systems in patients with bacteraemic pneumococcal pneumonia: implications for the intensive care unit care

Severity of illness scoring systems are useful for decisions on the management of patients with community-acquired pneumonia (CAP), including assessing the need for intensified therapy and monitoring, or for intensive care unit (ICU) admission. We compared the accuracy of the Pneumonia Severity Index (PSI), the CURB-65 and CRB-65 score, the modified-American Thoracic Society score (ATS), the IDSA/ATS guidelines and the Pitt Bacteraemia score (PBS) in evaluating severity of illness in 766 patients with bacteraemic pneumococcal pneumonia. We evaluated the sensitivity and specificity, the positive predictive value (PPV) and the negative predictive value (NPV) and the accuracy of the classification in predicting 14-day mortality. The PSI and the IDSA/ATS guidelines were the most sensitive whereas the PBS and modified-ATS scoring systems were the most specific in predicting mortality. The NPV was comparable for all four scoring systems (all above 90%), but the PPV was highest for PBS (54.2%) and lowest for PSI (23.2%). The predictive accuracy and discriminating power as measured by the receiver-operating characteristic (ROC) curve was highest for the PBS. Both the modified-ATS and the PBS scoring systems identified those patients who might benefit most from intensified care and monitoring. The PBS and modified-ATS proved superior to the IDSA/ATS guidelines, CURB-65 and CRB-65 with respect to their specificity and PPV. The low PPV of the PSI rendered it not usable as a parameter for decision-making in severely-ill patients with pneumococcal bacteraemia.

Severity scores for community-acquired pneumonia

An assessment of the severity of illness of a patient is one of the most important components of their early management. It guides decisions regarding the most appropriate site of care and the selection of empiric antibiotic therapy. In recent years, prediction tools, known as severity scores, have been promoted to assist early assessments of the severity of illness for patients with community-acquired pneumonia. Several different severity scores now exist and these have been modified over time. Each tool has particular strengths and weaknesses. This article reviews the evolution of severity scores for patients with community-acquired pneumonia and compares their performance in different patient cohorts for different outcomes of interest, as described in the published literature to date. It also discusses how these tools could be evaluated more comprehensively so that their place in patient management can be better appreciated.

Community-acquired pneumonia: doctors do not follow national guidelines

OBJECTIVES

Appropriate assessment of community-acquired pneumonia (CAP) allows accurate severity scoring and hence optimal management, leading to reduced morbidity and mortality. British Thoracic Society (BTS) guidelines provide an appropriate score. Adherence to BTS guidelines was assessed in our medical assessment unit (MAU) in 2001/2 and again in 2005/6, 3 years after introducing an educational programme.

METHODS

A retrospective case-note study, comparing diagnosis, documentation of severity, management and outcome of CAP during admission to MAU during 3 months of each winter in 2001/2 and 2005/6.

RESULTS

In 2001/2, 65/165 patients were wrongly coded as CAP and 100 were included in the study. In 2005/6 43/130 were excluded and 87 enrolled. In 2005/6, 87% did not receive a severity score, a significant increase from 48% in 2001/2 (p<0.0001). Parenteral antibiotics were given to 79% of patients in 2001/2 and 77% in 2005/6, and third generation cephalosporins were given to 63% in 2001/2 and 54% in 2005/6 (p = NS). In 2001, 15 different antibiotic regimens were prescribed, increasing to 19 in 2005/6.

CONCLUSIONS

Coding remains poor. Adherence to CAP management guidelines was poor and has significantly worsened. Educational programmes, alone, do not improve adherence. Restriction of antibiotic prescribing should be considered.

Prognostic scoring systems: which one is best?

PURPOSE OF REVIEW

In the initial evaluation of patients with community-acquired pneumonia, a number of important assessments are made, including that of the severity of the illness. This assessment will determine the appropriate site of care, diagnostic work-up, and choice of empiric antibiotics. A number of severity assessment tools have been developed and some of the recent findings are reviewed.

RECENT FINDINGS

A number of studies of the efficacy of the individual scoring systems, as well as comparator studies, have been undertaken. A significant number of patients with community-acquired pneumonia in Pneumonia Severity Index classes I and II are admitted to hospital and several of these patients suffer complications. Clinical and social factors other than those contained in the scoring systems need to be taken into consideration when deciding about hospitalization of patients with community-acquired pneumonia. A number of studies of the efficacy of the various scoring systems in predicting 'severe pneumonia' have been undertaken, as well as studies of their accuracy in the sub-set of patients with pneumococcal infections and in the elderly.

SUMMARY

The various scoring systems have reasonable sensitivity and specificity and their own strengths and weaknesses, but should always be used in association with good clinical judgment.

A prospective comparison of severity scores for identifying patients with severe community acquired pneumonia: reconsidering what is meant by severe pneumonia

BACKGROUND

Several severity scores have been proposed to predict patient outcome and to guide initial management of patients with community acquired pneumonia (CAP). Most have been derived as predictors of mortality. A study was undertaken to compare the predictive value of these tools using different clinically meaningful outcomes as constructs for "severe pneumonia".

METHODS

A prospective cohort study was performed of all patients presenting to the emergency department with an admission diagnosis of CAP from March 2003 to March 2004. Clinical and laboratory features at presentation were used to calculate severity scores using the pneumonia severity index (PSI), the revised American Thoracic Society score (rATS), and the British Thoracic Society (BTS) severity scores CURB, modified BTS severity score, and CURB-65. The sensitivity, specificity, positive and negative predictive values were compared for four different outcomes (death, need for ICU admission, and combined outcomes of death and/or need for ventilatory or inotropic support).

RESULTS

392 patients were included in the analysis; 37 (9.4%) died and 26 (6.6%) required ventilatory and/or inotropic support. The modified BTS severity score performed best for all four outcomes. The PSI (classes IV+V) and CURB had a very similar performance as predictive tools for each outcome. The rATS identified the need for ICU admission well but not mortality. The CURB-65 score predicted mortality well but performed less well when requirement for ICU was included in the outcome of interest. When the combined outcome was evaluated (excluding patients aged >90 years and those from nursing homes), the best predictors were the modified BTS severity score (sensitivity 94.3%) and the PSI and CURB score (sensitivity 83.3% for both).

CONCLUSIONS

Different severity scores have different strengths and weaknesses as prediction tools. Validation should be done in the most relevant clinical setting, using more appropriate constructs of "severe pneumonia" to ensure that these potentially useful tools truly deliver what clinicians expect of them.

Predicted effects on antibiotic use following the introduction of British or North American guidelines for community-acquired pneumonia in The Netherlands

This study evaluated the possible changes in antibiotic use that might follow the implementation of British or North American guidelines for the treatment of community-acquired pneumonia (CAP) in The Netherlands. Patients admitted for mild, moderate and severe CAP were evaluated prospectively. Volume of antibiotic use, based upon guidelines of the British Thoracic Society (BTS), the Infectious Diseases Society of America (IDSA) or the American Thoracic Society (ATS), was estimated and compared to current practice. For 248 patients, current antibiotic use was 3087 defined daily doses. Antibiotic use would increase by 38% if based on ATS guidelines, by 23% if based on IDSA guidelines, and by 21% if based on BTS guidelines. The most significant increase in antibiotic use would occur for cases of moderate CAP, with incremental antibiotic costs of 1 750 000-3 500 000 Euros in The Netherlands.

Severe community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia remains a prevalent and potentially life-threatening infection. In general, the disease is considered severe when inpatient care including ICU admission is required, and this often suggests a poorer prognosis. Severe community-acquired pneumonia continues to be an important subject of research from different perspectives, including assessment of illness severity, etiology, diagnostic tests, and treatment options. The aim of this descriptive review is to comment on the results of the relevant original articles in this area published since April 1, 2003.

RECENT FINDINGS

The main themes in the literature covered by the review include the time course of serum concentrations of different markers of the inflammatory response, validation of severity scores to optimize hospital and ICU admission, outcome improvement (duration of therapy and optimal dosing, time to antibiotic administration, adequate initial treatment, and the impact of positive microbiological diagnosis on management and prognosis), and the efficacy of new antimicrobials.

SUMMARY

The usefulness of inflammatory markers to assess the outcome of the disease is unclear. Data on severity scores are conclusive and different validated and simple predictive rules are available for the classification of patients into risk classes. Therapeutic strategies that have been investigated confirm the impact of adequate empiric antibiotic treatment on clinical outcome and the equivalence between short and long courses in the duration of therapy. A definitive beneficial effect of early administration of antimicrobials or the knowledge of the etiology of pneumonia on the clinical course of the disease has not been demonstrated.