Procalcitonin alone cannot diagnose pneumonia
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Procalcitonin can help predict which patients with community-acquired pneumonia may require intubation for respiratory failure during a hospital admission.

Compared to those with undetectable levels, patients with a procalcitonin of 5 ng/mL were three times more likely to require invasive respiratory support, and those with a 10 ng/mL level were five times more likely, reported Wesley Self, MD, and his colleagues (Chest. 2016;150[4]:819-28. doi: 10.1016/j.chest.2016.04.010).

While predictive accuracy isn’t good enough to merit use of procalcitonin as a stand-alone test, adding it to existing clinical management tools “is likely to improve identification of patients needing intensive care,” wrote Dr. Self of Vanderbilt University, Nashville, and his colleagues. “An elevated procalcitonin level may help identify these patients without overt clinical signs of impending respiratory failure or shock but who would benefit from early [intensive care unit] admission.”

The team examined serum procalcitonin as a biomarker in a subgroup of patients included in the Etiology of Pneumonia in the Community (EPIC) study of adults hospitalized with community-acquire pneumonia. The primary outcome was the need for invasive respiratory and/or vasopressor support (IRVS) within 72 hours.

Secondarily, they looked at whether adding procalcitonin boosted the performance of accepted pneumonia risk scores, including the American Thoracic Society minor criteria (ATS).

The cohort comprised 1,770 patients with a median age of 57 years. Of these, 115 (6.5%) needed IRVS within 72 hours of admission. Almost 16% were admitted directly into an intensive care unit; almost 7% experienced a delayed transfer from a medical unit into an ICU. The in-hospital mortality was about 2%.

Most (1,642) had an ATS score of less than 3; among these, about 5% needed IRVS. The remainder had a score of 3 or higher; about 30% required IRVS. All had procalcitonin levels pulled at admission. The levels were significantly higher among patients who required IRVS than those who didn’t (1.43 ng/mL vs. 0.14 ng/mL).

A multivariate analysis found that procalcitonin was strongly associated with the risk of IRVS. In patients with undetectable levels, the risk was 4%. At 5-10 ng/mL, the overall risk of IRVS was about 14%. Every 1-ng/mL increase in this range boosted the risk of IRVS by 1%-2%.

Adding the measurement of procalcitonin to traditional pneumonia severity risk scores significantly improved the patients’ performance. When stratified by ATS minor criteria, the risk of IRVS was 4.7% among low-risk patients. That decreased to 2.4% with the addition of undetectable procalcitonin, and increased to 12% with the addition of a 10 ng/mL level.

Conversely, without considering procalcitonin, ATS high-risk patients had almost a 30% risk of IRVS. Among these high-risk patients, IRVS risk dropped to 13% with undetectable procalcitonin and increased to 36% with high procalcitonin.

Adding the biomarker level to the ATS system improved its ability to correctly classify patients, the team said. “Using at least 3 ATS minor criteria alone to indicate high risk, 77 (4.4%) of the 1,770 total patients were misclassified as low-risk and experienced IRVS. Including procalcitonin of at least 0.83 ng/ml in addition … as a high-risk indicator reduced the number of patients with IRVS misclassified as low risk to 44 (2.5%). Adding procalcitonin of at least 0.83 ng/mL as a high-risk indicator resulted in 370 additional patients being classified as high risk, with 33 correctly classified as having IRVS.”

Dr. Self reported financial relationships with multiple pharmaceutical companies.

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While measuring procalcitonin adds valuable information to pneumonia risk stratification schemes, this process lacks the accuracy needed to enable the diagnosis of pneumonia as a stand-alone test, Daiana Stolz, MD, MPH, FCCP, wrote in an editorial.

“This study further supports the notion that procalcitonin has a limited prognostic accuracy as a stand-alone test. It also does not seem to outperform the risk estimation of a combination of clinical and laboratorial parameters. However, it also emphasizes its potential to capture nuances elusive to the clinical assessment, which do not seem to be consistently reflected even in elaborated severity scores recommended for clinical routine use,” she said (Chest. 2016;150[4]:769-71. doi: 10.1016/j.chest.2016.07.017).

[Procalcitonin] values vary according to the pneumonia severity and this association is stronger than the one between disease severity and other clinical and laboratory variables,” she said.

Risk scores like the ATS system can be weak, “in particular with regard to positive predictive values,” Dr. Stolz wrote. And this is an important issue. “It is clear that patients fulfilling major criteria (endotracheal intubation and mechanical ventilation; shock-requiring vasopressors) should be considered for ICU admission; however, there is still controversy about the value of the minor criteria. ICU care is costly and a limited resource worldwide.”

She called for “a randomized study evaluating the outcome and cost-effectiveness of a procalcitonin-refined clinical score in severe [community acquired pneumonia].”

Dr. Stolz is a pulmonologist at the University Hospital Basel, Switzerland. She reported financial relationships with several pharmaceutical companies.

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While measuring procalcitonin adds valuable information to pneumonia risk stratification schemes, this process lacks the accuracy needed to enable the diagnosis of pneumonia as a stand-alone test, Daiana Stolz, MD, MPH, FCCP, wrote in an editorial.

“This study further supports the notion that procalcitonin has a limited prognostic accuracy as a stand-alone test. It also does not seem to outperform the risk estimation of a combination of clinical and laboratorial parameters. However, it also emphasizes its potential to capture nuances elusive to the clinical assessment, which do not seem to be consistently reflected even in elaborated severity scores recommended for clinical routine use,” she said (Chest. 2016;150[4]:769-71. doi: 10.1016/j.chest.2016.07.017).

[Procalcitonin] values vary according to the pneumonia severity and this association is stronger than the one between disease severity and other clinical and laboratory variables,” she said.

Risk scores like the ATS system can be weak, “in particular with regard to positive predictive values,” Dr. Stolz wrote. And this is an important issue. “It is clear that patients fulfilling major criteria (endotracheal intubation and mechanical ventilation; shock-requiring vasopressors) should be considered for ICU admission; however, there is still controversy about the value of the minor criteria. ICU care is costly and a limited resource worldwide.”

She called for “a randomized study evaluating the outcome and cost-effectiveness of a procalcitonin-refined clinical score in severe [community acquired pneumonia].”

Dr. Stolz is a pulmonologist at the University Hospital Basel, Switzerland. She reported financial relationships with several pharmaceutical companies.

Body

 

While measuring procalcitonin adds valuable information to pneumonia risk stratification schemes, this process lacks the accuracy needed to enable the diagnosis of pneumonia as a stand-alone test, Daiana Stolz, MD, MPH, FCCP, wrote in an editorial.

“This study further supports the notion that procalcitonin has a limited prognostic accuracy as a stand-alone test. It also does not seem to outperform the risk estimation of a combination of clinical and laboratorial parameters. However, it also emphasizes its potential to capture nuances elusive to the clinical assessment, which do not seem to be consistently reflected even in elaborated severity scores recommended for clinical routine use,” she said (Chest. 2016;150[4]:769-71. doi: 10.1016/j.chest.2016.07.017).

[Procalcitonin] values vary according to the pneumonia severity and this association is stronger than the one between disease severity and other clinical and laboratory variables,” she said.

Risk scores like the ATS system can be weak, “in particular with regard to positive predictive values,” Dr. Stolz wrote. And this is an important issue. “It is clear that patients fulfilling major criteria (endotracheal intubation and mechanical ventilation; shock-requiring vasopressors) should be considered for ICU admission; however, there is still controversy about the value of the minor criteria. ICU care is costly and a limited resource worldwide.”

She called for “a randomized study evaluating the outcome and cost-effectiveness of a procalcitonin-refined clinical score in severe [community acquired pneumonia].”

Dr. Stolz is a pulmonologist at the University Hospital Basel, Switzerland. She reported financial relationships with several pharmaceutical companies.

Title
Procalcitonin alone cannot diagnose pneumonia
Procalcitonin alone cannot diagnose pneumonia

 

Procalcitonin can help predict which patients with community-acquired pneumonia may require intubation for respiratory failure during a hospital admission.

Compared to those with undetectable levels, patients with a procalcitonin of 5 ng/mL were three times more likely to require invasive respiratory support, and those with a 10 ng/mL level were five times more likely, reported Wesley Self, MD, and his colleagues (Chest. 2016;150[4]:819-28. doi: 10.1016/j.chest.2016.04.010).

While predictive accuracy isn’t good enough to merit use of procalcitonin as a stand-alone test, adding it to existing clinical management tools “is likely to improve identification of patients needing intensive care,” wrote Dr. Self of Vanderbilt University, Nashville, and his colleagues. “An elevated procalcitonin level may help identify these patients without overt clinical signs of impending respiratory failure or shock but who would benefit from early [intensive care unit] admission.”

The team examined serum procalcitonin as a biomarker in a subgroup of patients included in the Etiology of Pneumonia in the Community (EPIC) study of adults hospitalized with community-acquire pneumonia. The primary outcome was the need for invasive respiratory and/or vasopressor support (IRVS) within 72 hours.

Secondarily, they looked at whether adding procalcitonin boosted the performance of accepted pneumonia risk scores, including the American Thoracic Society minor criteria (ATS).

The cohort comprised 1,770 patients with a median age of 57 years. Of these, 115 (6.5%) needed IRVS within 72 hours of admission. Almost 16% were admitted directly into an intensive care unit; almost 7% experienced a delayed transfer from a medical unit into an ICU. The in-hospital mortality was about 2%.

Most (1,642) had an ATS score of less than 3; among these, about 5% needed IRVS. The remainder had a score of 3 or higher; about 30% required IRVS. All had procalcitonin levels pulled at admission. The levels were significantly higher among patients who required IRVS than those who didn’t (1.43 ng/mL vs. 0.14 ng/mL).

A multivariate analysis found that procalcitonin was strongly associated with the risk of IRVS. In patients with undetectable levels, the risk was 4%. At 5-10 ng/mL, the overall risk of IRVS was about 14%. Every 1-ng/mL increase in this range boosted the risk of IRVS by 1%-2%.

Adding the measurement of procalcitonin to traditional pneumonia severity risk scores significantly improved the patients’ performance. When stratified by ATS minor criteria, the risk of IRVS was 4.7% among low-risk patients. That decreased to 2.4% with the addition of undetectable procalcitonin, and increased to 12% with the addition of a 10 ng/mL level.

Conversely, without considering procalcitonin, ATS high-risk patients had almost a 30% risk of IRVS. Among these high-risk patients, IRVS risk dropped to 13% with undetectable procalcitonin and increased to 36% with high procalcitonin.

Adding the biomarker level to the ATS system improved its ability to correctly classify patients, the team said. “Using at least 3 ATS minor criteria alone to indicate high risk, 77 (4.4%) of the 1,770 total patients were misclassified as low-risk and experienced IRVS. Including procalcitonin of at least 0.83 ng/ml in addition … as a high-risk indicator reduced the number of patients with IRVS misclassified as low risk to 44 (2.5%). Adding procalcitonin of at least 0.83 ng/mL as a high-risk indicator resulted in 370 additional patients being classified as high risk, with 33 correctly classified as having IRVS.”

Dr. Self reported financial relationships with multiple pharmaceutical companies.

 

Procalcitonin can help predict which patients with community-acquired pneumonia may require intubation for respiratory failure during a hospital admission.

Compared to those with undetectable levels, patients with a procalcitonin of 5 ng/mL were three times more likely to require invasive respiratory support, and those with a 10 ng/mL level were five times more likely, reported Wesley Self, MD, and his colleagues (Chest. 2016;150[4]:819-28. doi: 10.1016/j.chest.2016.04.010).

While predictive accuracy isn’t good enough to merit use of procalcitonin as a stand-alone test, adding it to existing clinical management tools “is likely to improve identification of patients needing intensive care,” wrote Dr. Self of Vanderbilt University, Nashville, and his colleagues. “An elevated procalcitonin level may help identify these patients without overt clinical signs of impending respiratory failure or shock but who would benefit from early [intensive care unit] admission.”

The team examined serum procalcitonin as a biomarker in a subgroup of patients included in the Etiology of Pneumonia in the Community (EPIC) study of adults hospitalized with community-acquire pneumonia. The primary outcome was the need for invasive respiratory and/or vasopressor support (IRVS) within 72 hours.

Secondarily, they looked at whether adding procalcitonin boosted the performance of accepted pneumonia risk scores, including the American Thoracic Society minor criteria (ATS).

The cohort comprised 1,770 patients with a median age of 57 years. Of these, 115 (6.5%) needed IRVS within 72 hours of admission. Almost 16% were admitted directly into an intensive care unit; almost 7% experienced a delayed transfer from a medical unit into an ICU. The in-hospital mortality was about 2%.

Most (1,642) had an ATS score of less than 3; among these, about 5% needed IRVS. The remainder had a score of 3 or higher; about 30% required IRVS. All had procalcitonin levels pulled at admission. The levels were significantly higher among patients who required IRVS than those who didn’t (1.43 ng/mL vs. 0.14 ng/mL).

A multivariate analysis found that procalcitonin was strongly associated with the risk of IRVS. In patients with undetectable levels, the risk was 4%. At 5-10 ng/mL, the overall risk of IRVS was about 14%. Every 1-ng/mL increase in this range boosted the risk of IRVS by 1%-2%.

Adding the measurement of procalcitonin to traditional pneumonia severity risk scores significantly improved the patients’ performance. When stratified by ATS minor criteria, the risk of IRVS was 4.7% among low-risk patients. That decreased to 2.4% with the addition of undetectable procalcitonin, and increased to 12% with the addition of a 10 ng/mL level.

Conversely, without considering procalcitonin, ATS high-risk patients had almost a 30% risk of IRVS. Among these high-risk patients, IRVS risk dropped to 13% with undetectable procalcitonin and increased to 36% with high procalcitonin.

Adding the biomarker level to the ATS system improved its ability to correctly classify patients, the team said. “Using at least 3 ATS minor criteria alone to indicate high risk, 77 (4.4%) of the 1,770 total patients were misclassified as low-risk and experienced IRVS. Including procalcitonin of at least 0.83 ng/ml in addition … as a high-risk indicator reduced the number of patients with IRVS misclassified as low risk to 44 (2.5%). Adding procalcitonin of at least 0.83 ng/mL as a high-risk indicator resulted in 370 additional patients being classified as high risk, with 33 correctly classified as having IRVS.”

Dr. Self reported financial relationships with multiple pharmaceutical companies.

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Key clinical point: Procalcitonin can help predict which patients with community-acquired pneumonia require invasive respiratory support during a hospital admission.

Major finding: At a procalcitonin level of 5-10 ng/mL, the overall risk of invasive respiratory and/or vasopressor support was about 14%.

Data source: The analysis comprised 1,770 patients.

Disclosures: Dr. Self reported financial relationships with several pharmaceutical companies.