Utility of quick sepsis-related organ failure assessment (qSOFA) to predict outcome in patients with pneumonia

Background

Pneumonia, an acute infection of the pulmonary parenchyma, is a disease that commonly presents to US Emergency Departments, with an incidence as high as 9.7 per 1000 persons in developed countries.  Studies have found that community acquired pneumonia alone has a hospitalization rate of 46.5% and 30-day mortality of 12.9%, with a case fatality rate of over 50% in patients with pneumonia-related sepsis/septic shock (Kolditz 2016, Woodhead 2006).  Thus, the early identification of pneumonia-related sepsis is critical for the emergency physician. 

Over the years, multiple definitions of sepsis have been published, with sepsis now defined as a dysregulated host response to an external pathogen (Singer 2016).  Multiple diagnostic criteria have been utilized to identify sepsis, including the classic SIRS criteria and more recently the sequential organ failure (SOFA) score.  Given that these scoring systems require laboratory work-up, the international census committee most recently proposed the quick sequential organ failure score (qSOFA), which allows the clinician to rapidly assess parameters (respiratory rate, mental status, systolic blood pressure) at the bedside to identify critically ill patients.

Primary Results

• 612 patients with diagnosis of pneumonia
  • 527 patients included
  • 466 patients were hospitalized
• Overall in-hospital mortality: 13.3% (n=80)
• Admitted to the ICU: 22.0% (n=116)
• Median LOS: 7 days

Critical Findings

• qSOFA positive (>1) sensitivity
  • Prediction of in-hospital mortality: 26.6% 
  • Prediction of ICU admission: 48.4%
• qSOFA positive (>1) specificity
  • Prediction of in-hospital mortality: 88.3%
  • Prediction of ICU admission: 77.7%
• Area under the curve (AUC) for in-hospital mortality was 0.58, for ICU admission 0.66

Subgroup Analysis

• 346 patients included
• qSOFA and CURB-65 positive patients had increased in-hospital mortality with qSOFA having a higher AUC for ICU admission but not in-hospital mortality
• Clinical judgment and positive SIRS criteria: not associated with in-hospital mortality
• No significant differences between AUC for in-hospital mortality or ICU admissions for qSOFA vs. SIRS or qSOFA vs. clinically suspected sepsis.

Strengths

• The study intervention was simple and straightforward
• The studied topic is highly relevant to our clinical practice
• The scoring system (qSOFA) has previously validated in predicting outcomes in critically ill ED patients

Limitations

• The study was conducted in a single 40,000-bed hospital in Switzerland, limiting generalizability
• There was no discussion of the methods of chart review, absence of clinical data in the charts or inter-rater reliability in chart extraction
• The study was limited by utilizing prior medical records, which may have excluded information like risk factors and associated symptoms for each patient
• 77 patients were excluded for not having a documented respiratory rate.
• The study did not define the hospital’s admission criteria for ICU admission, a possible source of selection bias.
• Pneumonia diagnosis was confirmed only by documentation in medical records. This is a possible source of diagnosis bias
• The study population overall had high rates of hospital admission, in-hospital mortality and ICU admission for pneumonia, suggesting a sicker population relative to other populations we see in clinical practice.
• AUC information was not provided for CURB-65 or SIRS, making it difficult to compare

Author's Conclusions

“The qSOFA score is associated with in-hospital mortality, ICU admission and length of hospitalisation in ED patients with pneumonia. Subgroup analysis revealed that qSOFA is superior to CURB-65 in respect to prognostication of ICU admission.”

Our Conclusions

In this single-center retrospective study, qSOFA positive scores in patients with pneumonia-related sepsis were associated with higher in-hospital mortality and ICU admission rates, and may have a higher association with ICU admission when compared to CURB-65 scores.

Potential Impact To Current Practice

qSOFA allows for rapid assessment of patients with pneumonia-related sepsis, with higher scores having an association with in-hospital mortality and ICU admission in this study’s population. Thus, it may help guide clinicians early on in identifying patients with suspected infections that are at greater risk for poor outcomes. However, clinicians should not rely solely on these criteria when determining which patients may require a higher level of care, especially given the qSOFA’s low sensitivity.

Bottom Line

While a positive qSOFA score was associated with higher rates of in-hospital mortality and ICU admission in patients with pneumonia-related sepsis, we must take into consideration that at baseline, this study’s population may be sicker than those we see in our clinical practice. Further multi-center data may be useful to improve generalizability of these results.

Read More

References

Kolditz M et al. Burden and risk factors of ambulatory or hospitalized CAP: A population based cohort study. Respir Med. 2016; 121:32–8. PMID: 27888989

Woodhead M et al. Community-acquired pneumonia on the intensive care unit: secondary analysis of 17,869 cases in the ICNARC Case Mix Programme Database. Crit Care. 2006; 10 Suppl 2:S1. PMID: 16934135

Singer M et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016; 315(8):801–10. PMID: 26903338