SYNOPSIS: This prospective cohort study finds that high serum calcitonin levels upon admission are associated with elevated risk of invasive respiratory or vasopressor support (IRVS) within three days. Such findings allowed more accurate disease severity scores and improved the process for identifying high risk patients.
SOURCE: Self WH, Grijalva CG, Williams DJ, et al. Procalcitonin as an early marker of the need for invasive respiratory or vasopressor support in adults with community-acquired pneumonia. Chest 2016 Apr 20 [Epub ahead of print].
Recently there have been significant resources invested in the determination of whether procalcitonin (PCT) can serve as a reliable biomarker for critically ill sepsis patients. A few of the studies investigating PCT have emphasized its potential as a diagnostic indicator, a prognostic marker in sepsis, and a guideline for antibiotic treatment decisions in sepsis. Self et al, then, have added to the growing wealth of knowledge about this particular biomarker with their findings gleaned from examining whether PCT is helpful to ICUs in assessing disease severity and stratifying patients suffering from community-acquired pneumonia (CAP) by risk.
This study comprised 1,770 adults with serum PCT measurements taken who were hospitalized for CAP at five healthcare centers in Chicago and Nashville between 2010 and 2012. The primary measured outcome was the need for IRVS, classified as either vasopressor administration for septic shock or intubation following respiratory failure. Of the 1,770 adults included, 115 required IRVS. Thirty-one required vasopressors only, 37 required respiratory support only, and 47 required both.
At the conclusion of the study PCT level was significantly associated with IRVS risk. At undetectably low levels of PCT, the risk of IRVS was 4.0%. As PCT levels increased from 0.05 ng/mL to 10 ng/mL, there was a linear risk increase in IRVS risk. At the PCT levels of 5 ng/mL and 10 ng/mL, the risks for IRVS were 14.2% and 22.4%, respectively. IRVS risk rates plateaued, however, as PCT levels exceeded 10 ng/mL.
The authors conclude by affirming that including PCT levels along with current CAT severity scoring systems like the ATS Minor Criteria, Pneumonia Severity Index, and SMART-COP scores seriously improve risk stratification ability in predicting the need for IVRS at each severity score.