B Type Natriuretic Peptide as a Prognostic Marker in Acute Exacerbation of Chronic Obstructive Pulmonary Disease, Asthma and Pneumonia

Acute exacerbation of chronic obstructive pulmonary disease (COPD)/asthma and pneumonia are the major reason for the hospitalization and emergency room visit in the US. In 2011, chronic lower respiratory diseases and pneumonia were among top ten causes of mortality in 2011. Hospitalization and emergency room visit due to these morbidities account for high health care cost. B type natriuretic peptide level (BNP) of more than 400 is a prognostic and diagnostic marker for congestive heart failure (CHF). However, BNP can be raised in other conditions and significance of it is unknown.
Aims: To identify role of BNP in prognosticating asthma/copd exacerbation and pneumonia.
Study Design: Retrospective study.
Place and Duration of Study: Emergency room and Hospital at Interfaith Medical Center between January 2008 to July 2012.
Methodology: We retrospectively reviewed the charts of the patients admitted to our hospital with diagnosis of asthma, pneumonia and COPD in whom CHF had been ruled out. We collected data about BNP, length of stay, mortality and other demographic data.
Results: 461 patients met inclusion criteria - 28% had asthma, 31% had COPD exacerbation and 41% had pneumonia. 21% patients had BNP > 100 pg/ml. Patient with BNP > 100 pg/ml had higher mortality as compared to patients with BNP < 100 pg/ml- 19% and 2% respectively (P value .0001). Mean length of stay for BNP > 100 group and BNP < 100 groups were 8.7 and 5.56 days. (P value .0001). These differences were seen across the subgroups of asthma, COPD and Pneumonia. Patients with BNP > 100 pg/ml were more likely to required ICU care as compared to patients with BNP < 100 pg/ml – 30% vs 9% (P value .0001).
Conclusion: Our study suggests that BNP can be used as prognostic marker for mortality and severity of the disease in Asthma, COPD and Pneumonia. Higher BNP levels can also predict the prolong length of stay in the hospital.