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Contrasting qSOFA and SIRS Criteria for Early Sepsis Identification in a Veteran Population

The quick Sequential Organ Failure Assessment lacks sensitivity to be an effective replacement for the Systemic Inflammatory Response Syndrome criteria for sepsis screening.
Federal Practitioner. 2019 March;36(2)s:S21-S24
March 1, 2020|Federal Practitioner
Lisa A. Dykes, PharmD, BCPS, BCACP, MHA;Shannon J. Heintz, PharmD, BCPS;Brett H. Heintz, PharmD, BCPS AQ-ID, AAHIVE;Daniel J. Livorsi, MD, MS;Jason A. Egge, PharmD, BCPS, MS;Brian C. Lund, PharmD, MS
Author and Disclosure Information

Lisa Dykes is a Clinical Pharmacy Specialist at the ColumbiaVA Health Care System in South Carolina. Shannon Heintz and Brett Heintz are Clinical Pharmacy Specialists; Jason Egge and Brian Lund are Clinical Pharmacists; and Daniel Livorsi is an Infectious Diseases Physician; all at the Iowa City Veterans Affairs Health Care System in Iowa. Shannon Heintz is an Adjunct Associate Professor; Brett Heintz and Jason Egge are Adjunct Associate Professors; all at the University of Iowa College of Pharmacy in Iowa City. Daniel Livorsi is an assistant professor at the Division of Infectious Diseases, University of Iowa College of Medicine in Iowa City. Brian Lund is an adjunct assistant professor at the University of Iowa College of Public Health in Iowa City.
Correspondence: Lisa A Dykes (lisa.dykes2@va.gov)

Author disclosures
The authors report no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies.

Sepsis and Septic Shock Assessment Tools

As outlined in the Sepsis-3 guidelines, sepsis was defined as suspected or confirmed infection with an acute change in the SOFA score of ≥ 2 points, which is assumed to be 0 in those not known to have preexisting dysfunction.1 The SOFA score includes variables from the respiratory, coagulation, hepatic, cardiovascular, renal, and central nervous systems.1 Septic shock was defined as vasopressor administration and a serum lactic acid level > 2 mmol/L occurring up to 24 hours apart and within 3 days of the first antibiotic dose administered.

The SIRS assessment includes 4 clinical variables (temperature, heart rate, respiratory rate, and white blood cell count) while qSOFA is comprised of 3 variables (respiratory rate, systolic blood pressure, and altered mental status).1 With both assessments, a score ≥ 2 is considered positive, which indicates increased risk for sepsis in patients with suspected infection.1 In keeping with existing studies, qSOFA and SIRS assessments were scored using maximum values found within 48 hours before and 24 hours after the first administered antibiotic dose.3

Outcomes

The primary outcome variable was the presence of sepsis in adults with evidence of infection within 48 hours of admission. Secondary outcome measures included 30-day mortality and septic shock.

Performance between the SIRS and qSOFA assessments was contrasted using sensitivity, specificity, and positive and negative predictive value measurements. Associations of qSOFA and SIRS with septic shock and 30-day mortality were evaluated using a 2-tailed Fisher’s exact test with a threshold of α = 0.05 to determine statistical significance.

Results

The study sample of 481 veterans had a mean age of 67.4 years, 94% were male, and 91.1% were white (Table 1). 

When predicting risk for sepsis, the qSOFA demonstrated lower sensitivity than SIRS (44.7% vs 80.0%) but higher specificity (83.6% vs 25.7%) and higher positive predictive value (75.5% vs 54.8%) than did SIRS (Table 2). Specificity and positive predictive value results indicated a good probability that veterans with positive qSOFA assessments actually had sepsis.

Scores for qSOFA, but not SIRS, were significantly associated with septic shock (Fisher’s exact test; qSOFA: P = .009; SIRS: P = .58) (Table 3). 

Both assessments were significantly associated with increased risk for 30-day mortality (Fisher’s exact test; qSOFA: P < .001; SIRS: P = .025). In an additional analysis, scores for SOFA were not significantly associated with septic shock (Fisher’s exact test, P = .13) but were significantly associated with an increased risk for 30-day mortality (Fisher’s exact test, P = .016) (Table 4).

Discussion

High sensitivity is critical for a sepsis screening tool. To be clinically useful, it has been suggested that biomarkers predicting poor outcomes for sepsis should have a sensitivity of > 80%.4 Although qSOFA demonstrated greater specificity than SIRS in our study (83.6% vs 25.7%), qSOFA showed lower sensitivity (44.7% vs 80.0%), which resulted in a greater potential for false negatives; 55.3% of those with sepsis would go undetected. Therefore, our study does not support qSOFA as a better screening assessment than SIRS for sepsis in the veteran population.

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