Is It Pneumonia, Heart Failure, or Both? Biomarkers Can Help Diagnose Dyspnea

Acutely ill patients tend to have similar complaints. One of the most common is dyspnea, or shortness of breath (SOB). But therein lies the rub: There are a variety of etiologies for SOB arising from disparate organ systems. Two of the most important of these are pneumonia or heart failure, or sometimes both pathologies at once. In fact, rates of in-hospital mortality and 60- to 90-day mortality for heart failure are 8% and 13%, respectively; if heart failure and pneumonia are both present, the mortality rate jumps to 20%.¹

A recent Top Paper¹ looks at what the measurement of serum procalcitonin (PCT) levels add to diagnostic certainty, specifically in regard to pneumonia (in subjects with heart failure also evaluated with amino-terminal pro-B type natriuretic peptide testing) in patients presenting to an emergency department with SOB. These patients also were rigorously studied with typical diagnostic modalities such as history and physical, chest radiography, and other laboratory studies.

The cohort comprised 2 separate but complementary populations: enrollees in the ProBNP Investigation of Dyspnea in the Emergency Department (PRIDE) study,² and enrollees in the Biomonitoring and Cardiorenal Syndrome in Heart Failure (BIONICS-HF) study.³

The total number of patients from the 2 populations was 453. Pneumonia alone (that is, without heart failure) was diagnosed in 30 patients. Heart failure alone was diagnosed in another 212 patients. Finally, both heart failure and pneumonia were present in 30 patients. The design suggested that the information obtained from PCT levels was “tight” in that the area under receiving operating characteristic curve was 0.84 (95% confidence interval [CI], 0.77-0.91; P < .001). In addition, an elevated PCT level was a predictor of 1-year mortality (hazard ratio 1.8; 95% CI, 1.4-2.3; P < .001).¹

Pneumonia and heart failure contribute $4.3 billion in annual hospital costs!¹ Physicians and other health care professionals work in a health system in which the history, the physical, imaging studies, and echocardiography assist in diagnosis. Now, biomarkers such as natriuretic peptides add to diagnostic certainty without adding invasive approaches. This Top Paper suggests that measurement of serum PCT levels has a place in the biomarker evaluation of pneumonia in a specific clinical context (that is, comorbid heart failure).

If one were to criticize this study, the size of the patient cohort was not large, and the number of pneumonia diagnoses was low compared with the number of heart failure diagnoses. That said, the study is helpful in a select group of patients who have a higher mortality and who incur a great expense to the health care system. Heart failure and pneumonia patients are a sicker population, and when both illnesses are present simultaneously, these individuals are need of early, directed care.

Gregory W. Rutecki, MD, is a physician at the National Consult Service at the Cleveland Clinic. He is also a member of the editorial board of Consultant. Dr Rutecki reports that he has no relevant financial relationships to disclose.

References:

1. Alba GA, Truong QA, Gaggin HK, et al; Global Research on Acute Conditions Team (GREAT) Network. Diagnostic and prognostic utility of procalcitonin in patients presenting to the emergency department with dyspnea. Am J Med. 2016;129(1):96-104.e7.
2. Januzzi JL Jr, Camargo CA, Anwaruddin S, et al. The N-Terminal Pro-BNP Investigation of Dyspnea in the Emergency Department (PRIDE) study. Am J Cardiol. 2005;95(8):948-954.
3. De Berardinis B, Gaggin HK, Magrini L, et al; Global Research on Acute Conditions Team (GREAT). Comparison between admission natriuretic peptides, NGAL and sST2 testing for the prediction of worsening renal function in patients with acutely decompensated heart failure. Clin Chem Lab Med. 2015;53(4):613-621.