Proadrenomedullin biomarker improves risk stratification and site of care decision in pneumonia patients

Initial severity assessment of emergency department patients with lower respiratory tract infections (LRTI) remains a clinical challenge. IHE spoke to Dr Philipp Schuetz, associate professor of internal medicine of the Medical University Clinic in Aarau, Switzerland, about his experience with ProADM, a new biomarker that has great potential to improve the current triage practice and thus site of care decisions.

Q. Is the risk assessment of patients who suffer from lower respiratory tract infection (LRTI) still a clinical need in hospitals?

Yes, LRTI is a serious condition associated with a significant rate of morbidity and long-term mortality. Additionally, LRTI has a major impact on the use of resources and healthcare expenditure. Although most patients are treated on an outpatient basis, the costs for hospitalized pneumonia patients can be 25 times higher [1]. Therefore, whether or not to hospitalize a patient is clinically of outmost importance and a very costly decision. Severity scores such as Pneumonia Severity Index (PSI) and/or the CURB65 were developed to aid the site of care decision and safely assess the risk of pneumonia patients. However, these scores have significant shortcomings which limit their applicability in routine care. First of all, they focus on mortality only, rather than on other complications, Secondly, they are static and do not include changes of the condition over time. Finally, they perform sub-optimally which should be improved to be able to make safe decisions for individual patients. Thus, there is still room to improve the current risk assessment tools and blood biomarkers like Proadrenomedullin (ProADM) which seems to show great potential in filling this gap [2-5].

Q. What is ProADM? How does it improve risk assessment in LRTI patients?

ProADM (mid-regional proAdrenomedullin) is a stable surrogate marker for Adrenomedullin (ADM). ADM belongs to the family of Calcitonin related peptides, similar to Procalcitonin (PCT). ADM is the most potent vasodilator and is activated in different stages of severe illness, such as sepsis and systemic infections. Unlike PCT, ADM is not specific to infections, but increases in different conditions that correlate with severity and adverse outcome across different medical diseases. Therefore, ProADM is not a diagnostic marker for sepsis, but has prognostic abilities. Importantly, proADM is also dynamic over time and the levels decrease when a patient improves; it also correlates with the risk of adverse events.

In several studies, ProADM showed a high correlation with the severity of LRTI; it was better than other commonly used parameters (WBC, PCT and CRP) and as powerful as PSI and CURB-65. Interestingly, when ProADM was used in addition to clinical risk scores, the accuracy of PSI and CURB-65 for risk prediction was improved for both short-term and long-term mortality.

Q. What is the benefit of adding ProADM to clinical risk assessment?

ProADM allows physicians to objectively estimate a patient