Investigation of the ability of the Pneumonia Severity Index to accurately predict clinically relevant outcomes: a European study

Progression of the Radiologic Severity Index is associated with increased mortality and healthcare resource utilisation in acute leukaemia patients with pneumonia

Background

Pneumonia is a major cause of mortality and morbidity, but the development of new antimicrobials is lacking. Radiological assessment of pneumonia severity may serve as an effective intermediate endpoint to reduce barriers to successful completion of antimicrobial trials. We sought to determine whether the Radiologic Severity Index (RSI) correlated with mortality and healthcare resource utilisation in patients with acute leukaemia undergoing induction chemotherapy.

Methods

We measured RSI (range 0–72) on all chest radiographs performed within 33 days of induction chemotherapy in 165 haematological malignancy patients with pneumonia. Peak RSI was defined as the highest RSI score within 33 days of induction. We used extended Cox proportional hazards models to measure the association of time-varying RSI with all-cause mortality within the first 33 days after induction chemotherapy, and logistic regression or generalised models to measure the association of RSI with total daily cost and healthcare resource utilisation.

Results

After adjustment for clinical variables, each one-point increase in RSI was associated with a 7% increase in all-cause 33-day mortality (HR 1.07, 95% CI 1.05 to 1.09, p<0.0001). Peak RSI values of 37.5 or higher were associated with 86% higher daily direct costs (p<0.0001), more days in intensive care unit (9.9 vs 4.8 days, p=0.001) and higher odds for mechanical ventilation (OR 12.1, p<0.0001).

Conclusions

Greater radiological severity as measured by RSI was associated with increased mortality and morbidity in acute leukaemia patients with pneumonia. RSI is a promising intermediate marker of pneumonia severity and is well suited for use in antimicrobial trials.

The Cost-Effectiveness of Corticosteroids for the Treatment of Community-Acquired Pneumonia

BACKGROUND

The use of corticosteroids as adjunct treatment for community-acquired pneumonia (CAP) is associated with potential clinical benefits. The aim of this study was to evaluate the cost-effectiveness of this approach.

METHODS

We constructed a decision-analytic model comparing the use of corticosteroids + antibiotics with that of placebo + antibiotics for the treatment of CAP. Cost-effectiveness was determined by calculating deaths averted and incremental cost-effectiveness ratios. Uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds.

RESULTS

In the base-case analysis, corticosteroids + antibiotics resulted in savings of $142,795 per death averted. In the probabilistic analysis, at a willingness to pay of $50,000, corticosteroids + antibiotics had a 86.4% chance of being cost-effective compared with placebo + antibiotics. In cost-effectiveness acceptability curves, the corticosteroids + antibiotics strategy was cost-effective in 87.6% to 94.3% of simulations compared with the placebo + antibiotics strategy for a willingness to pay ranging from $0 to $50,000. In patients with severe CAP (Pneumonia Severity Index classes IV/V) the corticosteroids + antibiotics strategy resulted in savings of $70,587 and had a 82.6% chance of being cost-effective compared with the placebo + antibiotics strategy.

CONCLUSIONS

The use of corticosteroids + antibiotics is a cost-effective strategy and results in considerable health care cost-savings, especially among patients with severe CAP (Pneumonia Severity Index classes IV/V).

Prognostic value of severity indicators of nursing-home-acquired pneumonia versus community-acquired pneumonia in elderly patients

BACKGROUND

The credibility of prognostic indicators in nursing-home-acquired pneumonia (NHAP) is not clear. We previously reported a simple prognostic indicator in community-acquired pneumonia (CAP): blood urea nitrogen to serum albumin (B/A) ratio. This retrospective study investigated the prognostic value of severity indicators in NHAP versus CAP in elderly patients.

METHODS

Patients aged ≥65 years and hospitalized because of NHAP or CAP within the previous 3 years were enrolled. Demographics, coexisting illnesses, laboratory and microbiological findings, and severity scores (confusion, urea, respiratory rate, blood pressure, and age ≥65 [CURB-65] scale; age, dehydration, respiratory failure, orientation disturbance, and pressure [A-DROP] scale; and pneumonia severity index [PSI]) were retrieved from medical records. The primary outcome was mortality within 28 days of admission.

RESULTS

In total, 138 NHAP and 307 CAP patients were enrolled. Mortality was higher in NHAP (18.1%) than in CAP (4.6%) (P<0.001). Patients with NHAP were older and had lower functional status and a higher rate of do-not-resuscitate orders, heart failure, and cerebrovascular diseases. The NHAP patients more frequently had typical bacterial pathogens. Using the receiver-operating characteristics curve for predicting mortality, the area under the curve in NHAP was 0.70 for the A-DROP scale, 0.69 for the CURB-65 scale, 0.67 for the PSI class, and 0.65 for the B/A ratio. The area under the curve in CAP was 0.73 for the A-DROP scale, 0.76 for the CURB-65 scale, 0.81 for the PSI class, and 0.83 for the B/A ratio.

CONCLUSION

Patient mortality was greater in NHAP than in CAP. Patient characteristics, coexisting illnesses, and detected pathogens differed greatly between NHAP and CAP. The existing severity indicators had less prognostic value for NHAP than for CAP.

Reduction of pediatric emergency hospital admissions by a change in pediatric emergency department policy

Background:

Reduction in admissions is an important aim of emergency department working policy to overcome the problems of a shortage of inpatient beds, rising costs and exhausted resources. A new policy was instituted in the pediatric emergency department (PED) of a hospital in Kuwait with the following components: (1) assigning senior doctor staff (2) implementation of new disease management guidelines; and (3) maximizing the use of the pediatric emergency department observation unit.

Objective:

to evaluate the effect of change in our policy on the admission rate.

Materials and Methods:

The effects of this policy on reduction of admission rates for total pediatric admissions and for some selected common pediatric conditions were prospectively studied over a period of 3 years from institution of the policy and compared with the 3-year period before the policy was instituted.

Results:

There was a significant reduction in admission rates after institution of the new policy. The proportion of hospital admissions to PED observation unit cases was significantly reduced as a whole from 64.9% ± 5.1% to 33.2 ± 0.6% and also for the common pediatric problems studied.

Conclusion:

A multidisciplinary pediatric emergency department policy, using as much available evidence as possible, was successful in significantly reducing pediatric hospital admissions.

Proadrenomedullin improves Risk of Early Admission to ICU score for predicting early severe community-acquired pneumonia

BACKGROUND

Whether proadrenomedullin (ProADM) improves the performance of the Risk of Early Admission to ICU (REA-ICU) score in predicting early, severe community-acquired pneumonia (ESCAP) has not been demonstrated.

METHODS

Secondary analysis was completed of the original data from 877 consecutive patients with community-acquired pneumonia (CAP) enrolled in the Procalcitonin-Guided Antibiotic Therapy and Hospitalization in Patients With Lower Respiratory Tract Infections (ProHOSP) study, a multicenter trial in EDs of six tertiary-care hospitals in Switzerland. ESCAP was defined by either the requirement for mechanical ventilation or vasopressive drugs or occurrence of death within 3 days of ED presentation.

RESULTS

Eighty patients (9.1%) developed ESCAP (47 required mechanical ventilation, 19 vasopressive drugs, and 16 died) within 3 days of ED presentation. They had a higher median ProADM value (2.18 nmol/L vs 1.15 nmol/L, P < .001). Combining ProADM testing with the REA-ICU score improved the area under the curve (0.81) compared with either parameter (ProADM [0.73] or REA-ICU score [0.76], P < .001) and resulted in a net reclassification improvement of 0.20 (P < .001). A ProADM value ≥ 1.8 nmol/L or assignment to REA-ICU risk classes III-IV predicted ESCAP with a sensitivity of 76.3% and a negative predictive value of 96.7%. Excluding 21 patients with major criteria of severe CAP on presentation showed similar results.

CONCLUSION

These study findings demonstrate that the addition of ProADM to the REA-ICU score improves the classification of a substantial proportion of patients in the ED at intermediate or high risk for ESCAP, which may translate into better triage decisions.

Prediction of severe community-acquired pneumonia: a systematic review and meta-analysis

Introduction

Severity assessment and site-of-care decisions for patients with community-acquired pneumonia (CAP) are pivotal for patients' safety and adequate allocation of resources. Late admission to the intensive care unit (ICU) has been associated with increased mortality in CAP. We aimed to review and meta-analyze systematically the performance of clinical prediction rules to identify CAP patients requiring ICU admission or intensive treatment.

Methods

We systematically searched Medline, Embase, and the Cochrane Controlled Trials registry for clinical trials evaluating the performance of prognostic rules to predict the need for ICU admission, intensive treatment, or the occurrence of early mortality in patients with CAP.

Results

Sufficient data were available to perform a meta-analysis on eight scores: PSI, CURB-65, CRB-65, CURB, ATS 2001, ATS/IDSA 2007, SCAP score, and SMART-COP. The estimated AUC of PSI and CURB-65 scores to predict ICU admission was 0.69. Among scores proposed for prediction of ICU admission, ATS-2001 and ATS/IDSA 2007 scores had better operative characteristics, with a sensitivity of 70% (CI, 61 to 77) and 84% (48 to 97) and a specificity of 90% (CI, 82 to 95) and 78% (46 to 93), but their clinical utility is limited by the use of major criteria.

ATS/IDSA 2007 minor criteria have good specificity (91% CI, 84 to 95) and moderate sensitivity (57% CI, 46 to 68). SMART-COP and SCAP score have good sensitivity (79% CI, 69 to 97, and 94% CI, 88 to 97) and moderate specificity (64% CI, 30 to 66, and 46% CI, 27 to 66). Major differences in populations, prognostic factor measurement, and outcome definition limit comparison. Our analysis also highlights a high degree of heterogeneity among the studies.

Conclusions

New severity scores for predicting the need for ICU or intensive treatment in patients with CAP, such as ATS/IDSA 2007 minor criteria, SCAP score, and SMART-COP, have better discriminative performances compared with PSI and CURB-65. High negative predictive value is the most consistent finding among the different prediction rules. These rules should be considered an aid to clinical judgment to guide ICU admission in CAP patients.

Outcomes of early, late, and no admission to the intensive care unit for patients hospitalized with community-acquired pneumonia

OBJECTIVES

The objective was to compare outcomes associated with early, late, and no admission to the intensive care unit (ICU) for patients hospitalized with community-acquired pneumonia (CAP).

METHODS

This was a post hoc analysis of the original data from the Emergency Department Community-Acquired Pneumonia (EDCAP) and Pneumocom-1 prospective multicenter cohort studies of adult patients hospitalized with CAP. Propensity score-adjusted analysis was used to compare 28-day mortality and hospital length of stay (LOS) for 199, 144, and 2,215 patients with early (i.e., ICU admission on the day of emergency department [ED] presentation), late, and no ICU admission.

RESULTS

Unadjusted 28-day mortality rates were 13.1, 19.4, and 5.7% for early, late, and no ICU admissions, respectively (p < 0.001). After adjusting for quintile of propensity score, the odds of 28-day mortality were higher for late ICU admissions relative to early ICU admissions (odds ratio [OR] = 2.63; 95% confidence interval [CI] = 1.42 to 4.90), and no ICU admissions (OR = 3.40; 95% CI = 2.11 to 5.48), but did not differ between early and no ICU admissions (OR = 1.29; 95% CI = 0.79 to 2.09). The median hospital LOS was 10 days for early (interquartile range [IQR] = 7 to 18), 15 days for late (IQR 9 to 23), and 6 days (IQR 4 to 9) for no ICU admissions (p < 0.001).

CONCLUSIONS

This study suggests that late but not early admission to the ICU is associated with higher 28-day mortality for patients hospitalized with CAP. Patients admitted to the ICU have longer hospital LOS in comparison to those managed on the wards, particularly if they are admitted late to the ICU.

Validation of the Infectious Diseases Society of America/American Thoratic Society minor criteria for intensive care unit admission in community-acquired pneumonia patients without major criteria or contraindications to intensive care unit care

BACKGROUND

The 2007 Infectious Disease Society of America/American Thoracic Society (IDSA/ATS) guidelines for community-acquired pneumonia (CAP) recommended new criteria to guide admission to the intensive care unit (ICU) for patients with this condition. Although the major criteria (requirement for mechanical ventilation or septic shock requiring vasopressor support) are well established, the value of the minor criteria alone have not been fully validated.

METHODS

We performed a prospective observational study of consecutive adult patients with CAP admitted to NHS Lothian (Scotland, United Kingdom). Patients meeting the IDSA/ATS major criteria on admission were excluded, along with patients not suitable for ICU care owing to advanced directives or major comorbid illnesses. Performance characteristics for the IDSA/ATS minor criteria were calculated and compared with those for alternative scoring systems identified in the literature. Two definitions of severe CAP were used as primary end points: ICU admission, and subsequent requirement for mechanical ventilation or vasopressor support (MV/VS); 30-day mortality was a secondary outcome.

RESULTS

The study included 1062 patients with CAP potentially eligible for ICU admission. Each of the 9 minor criteria was associated with increased risk of MV/VS and 30-day mortality in univariate analysis. Two hundred seven patients had ≥ 3 minor criteria (19.5%). The IDSA/ATS 2007 criteria had an area under the receiver operating characteristic curve of 0.85 (0.82-0.88) for prediction of MV/VS, 0.85 (0.82-0.88) for prediction of ICU admission, and 0.78 (0.74-0.82) for prediction of 30-day mortality. The IDSA/ATS 2007 criteria were at least equivalent to more established scoring systems for prediction of MV/VS and ICU admission and equivalent to alternative scoring systems for predicting 30-day mortality in this patient population.

CONCLUSIONS

In a population of patients with CAP without contraindications to ICU care, the IDSA/ATS minor criteria predict subsequent requirement for MV/VS, ICU admission, and 30-day mortality.

Predicting mortality with severity assessment tools in out-patients with community-acquired pneumonia

INTRODUCTION

In community-acquired pneumonia, severity assessment tools, such as CRB65, CURB65 and Pneumonia Severity Index (PSI), have been promoted to increase the proportion of patients treated in the community. The prognostic accuracy of these scores is established in hospitalized patients, but less is known about their use in out-patients. We aimed to study the accuracy of these severity tools to predict mortality in patients managed as out-patients.

METHODS

We performed a systematic review and meta-analysis according to MOOSE guidelines. From 1980 to 2010, we identified 13 studies reporting prognostic information for the CRB65, CURB65 and PSI severity scores in out-patients (either exclusively managed in the community or discharged from an emergency department <24 h after admission). Two reviewers independently collected data and assessed study quality. Performance characteristics across the studies were pooled using a random-effects model. Relationships between sensitivity and specificity were plotted using summary receiver operator characteristic curves (sROC).

RESULTS

Out-patient mortality ranged from 0% to 3.5%. Four studies were identified for CRB65, 2 for CURB65 and 10 for PSI. Mortality was low for out-patients in the low-risk CRB65 classes [CRB65 0 or 1: mortality occurred in 3 of 1494 patients (0.2%)] but higher in CRB65 Groups 2-4 [mortality 13 of 154 patients (8.4%)]. Similarly, mortality was low in PSI Classes I-III [mortality 8 of 3655 patients (0.2%)] managed as out-patients but higher in Classes IV and V [mortality 32 of 317 patients (10.1%)]. CRB65 showed pooled sensitivity of 81% (54-96%), pooled specificity of 91% (90-93%) and the area under the sROC was 0.91 [standard error (SE) 0.05]. For PSI, pooled sensitivity was 92% (64-100%), pooled specificity was 90% (89-91%) and area under the sROC was 0.92 (SE 0.03). There were insufficient studies to analyse CURB65.

CONCLUSION

The limited data available suggest that CRB65 and PSI can identify groups of patients at low risk of mortality that can be safely managed in the community.

Severity assessment tools to guide ICU admission in community-acquired pneumonia: systematic review and meta-analysis

BACKGROUND

The aim of this meta-analysis was to determine if severity assessment tools can be used to guide decisions regarding intensive care unit (ICU) admission of patients with community-acquired pneumonia.

METHODS

A search of PUBMED and EMBASE (1980-2009) was conducted to identify studies reporting pneumonia severity scores and prediction of ICU admission. Two reviewers independently collected data and assessed study quality. Performance characteristics were pooled using a random-effects model.

RESULTS

Sufficient data were collected to perform a meta-analysis on five current scoring systems: the Pneumonia Severity Index (PSI), the CURB65 score, the CRB65 score, the American Thoracic Society (ATS) 2001 criteria and the Infectious Disease Society of America/ATS (IDSA/ATS) 2007 criteria. The analysis was limited due to large variations in the ICU admission criteria, ICU admission rates and patient characteristics between different studies and different healthcare systems. In the pooled analysis, PSI, CURB65 and CRB65 performed similarly in terms of sensitivity and specificity across a range of cut-offs. Patients in CURB65 group 0 were at lowest risk of ICU admission (negative likelihood ratio 0.14; 95% confidence interval 0.06-0.34) while the ATS 2001 criteria had the highest positive likelihood ratio (7.05; 95% confidence interval 4.39-11.3).

CONCLUSION

Large variations exist in the use of ICU resources between different studies and different healthcare systems. Scoring systems designed to predict 30-day mortality perform less well when ICU admission is taken into account. Further studies of dedicated ICU admission scores are required.

Validation and comparison of SCAP as a predictive score for identifying low-risk patients in community-acquired pneumonia

PURPOSES

(1) To validate the Severe Community Acquired Pneumonia (SCAP) score in predicting 30-day mortality. (2) To validate its ability to identifying patients at low risk of death. (3) To compare it against the Pneumonia Severity Index (PSI), and the British Thoracic Society's CURB-65 rules.

METHODS

The SCAP score was validated to predict 30-day mortality in an internal validation cohort of consecutive adult patients seen in one hospital. Consecutive inpatients from other three hospitals were used to externally validate the score and compare the SCAP with the PSI and CURB-65. The discriminatory power of these rules to predict 30-day mortality was tested by the Area under Curve (AUC), and their predictive accuracy with the sensitivity, specificity and predictive values.

RESULTS

The 30-day mortality rate increased directly with increasing SCAP score (class 0: 0.5%, to class 4: 66.5% risk) in the internal validation cohort, and from 1.3% to 29.2% in external cohort (P<0.001) with an AUC of 0.83 and 0.75, respectively (P=0.024). The SCAP score identified 62.4% (95% IC 58.8-66.0) low-risk patients, 52.5% (95% IC 48.8-56.2) the PSI and 46.2% (95% CI 42.5-49.9) the CURB-65 in the external cohort. Patients classified as low risk by the three rules had similar 30-day mortality (SCAP: 2.5%, PSI: 1.6% and CURB-65: 2.7%).

CONCLUSION

The SCAP is valid to predict 30-day mortality among low-risk patients and identifies a larger proportion of patients as low-risk than the other studied rules.

Association between timing of intensive care unit admission and outcomes for emergency department patients with community-acquired pneumonia

OBJECTIVE

To compare the 28-day mortality and hospital length of stay of patients with community-acquired pneumonia who were transferred to an intensive care unit on the same day of emergency department presentation (direct-transfer patients) with those subsequently transferred within 3 days of presentation (delayed-transfer patients).

DESIGN

Secondary analysis of the original data from two North American and two European prospective, multicenter, cohort studies of adult patients with community-acquired pneumonia.

PATIENTS

In all, 453 non-institutionalized patients transferred within 3 days of emergency department presentation to an intensive care unit were included in the analysis. Supplementary analysis was restricted to patients without an obvious indication for immediate transfer to an intensive care unit.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The sample consisted of 138 delayed-transfer and 315 direct-transfer patients, among whom 150 (33.1%) were considered to have an obvious indication for immediate intensive care unit admission. After adjusting for the quintile of propensity score, delayed intensive care unit transfer was associated with an increased odds ratio for 28-day mortality (2.07; 95% confidence interval, 1.12-3.85) and a decreased odds ratio for discharge from hospital for survivors (0.53; 95% confidence interval, 0.39-0.71). In a propensity-matched analysis, delayed-transfer patients had a higher 28-day mortality rate (23.4% vs. 11.7%; p = 0.02) and a longer median hospital length of stay (13 days vs. 7 days; p < .001) than direct-transfer patients. Similar results were found after excluding the 150 patients with an obvious indication for immediate intensive care unit admission.

CONCLUSIONS

Our findings suggest that some patients without major criteria for severe community-acquired pneumonia, according to the recent Infectious Diseases Society of America/American Thoracic Society consensus guideline, may benefit from direct transfer to the intensive care unit. Further studies are needed to prospectively identify patients who may benefit from direct intensive care unit admission despite a lack of major severity criteria for community-acquired pneumonia based on the current guidelines.

Risk stratification of early admission to the intensive care unit of patients with no major criteria of severe community-acquired pneumonia: development of an international prediction rule

Introduction

To identify risk factors for early (< three days) intensive care unit (ICU) admission of patients hospitalised with community-acquired pneumonia (CAP) and not requiring immediate ICU admission, and to stratify the risk of ICU admission on days 1 to 3.

Methods

Using the original data from four North American and European prospective multicentre cohort studies of patients with CAP, we derived and validated a prediction rule for ICU admission on days 1 to 3 of emergency department (ED) presentation, for patients presenting with no obvious reason for immediate ICU admission (not requiring immediate respiratory or circulatory support).

Results

A total of 6560 patients were included (4593 and 1967 in the derivation and validation cohort, respectively), 303 (4.6%) of whom were admitted to an ICU on days 1 to 3. The Risk of Early Admission to ICU index (REA-ICU index) comprised 11 criteria independently associated with ICU admission: male gender, age younger than 80 years, comorbid conditions, respiratory rate of 30 breaths/minute or higher, heart rate of 125 beats/minute or higher, multilobar infiltrate or pleural effusion, white blood cell count less than 3 or 20 G/L or above, hypoxaemia (oxygen saturation < 90% or arterial partial pressure of oxygen (PaO₂) < 60 mmHg), blood urea nitrogen of 11 mmol/L or higher, pH less than 7.35 and sodium less than 130 mEq/L. The REA-ICU index stratified patients into four risk classes with a risk of ICU admission on days 1 to 3 ranging from 0.7 to 31%. The area under the curve was 0.81 (95% confidence interval (CI) = 0.78 to 0.83) in the overall population.

Conclusions

The REA-ICU index accurately stratifies the risk of ICU admission on days 1 to 3 for patients presenting to the ED with CAP and no obvious indication for immediate ICU admission and therefore may assist orientation decisions.