Various techniques have been developed to assess the severity of community-acquired pneumonia (CAP), to help with early diagnosis and treatment decisions, and to select the most appropriate environment for each patient. Severity scores, most notably the Pneumonia Severity Index and CURB65, were widely used and had demonstrated clinical utility in identifying patients with a low risk of 30-day mortality and who can be safely treated as outpatients, thereby improving treatment site selection and accelerating discharges. The ATS/IDSA score’s nine minor criteria outperformed the Pneumonia Severity Index and the CURB65 in identifying patients who required intensive care unit (ICU) admission. However, numerous important prognostic factors linked with CAP morbidity and mortality, such as clinical worsening, aggravation of underlying comorbidities, cardiovascular events, treatment failure, and sequelae, were not adequately predicted by these severity scores. A number of biomarkers had been evaluated for their capacity to detect severe CAP and choose the optimum treatment site. Inflammatory biomarkers, especially C-reactive protein (CRP) and procalcitonin (PCT), were used to assess the inflammatory response, which was linked to CAP mortality and severity. They’ve been shown to be useful in supplementing clinical severity scores and in tracking therapeutic response, complications, treatment failure, mortality, and the overall outcome of CAP. 

Both indicators employed in isolation in clinical practice, however, have significant limitations, particularly in terms of discriminating high-risk patients. Because sepsis and cardiovascular events played such a large role in CAP outcomes, various cardiovascular indicators had been investigated. Proadrenomedullin (proADM) proved to be a stronger predictor of short- and long-term mortality, severity, and comorbidities than inflammatory biomarkers. ProADM showed a good capacity to detect low-risk individuals, and adding it to clinical risk assessments boosts their predictive value dramatically. These relationships had the potential to help patients with CAP make better site-of-care decisions and release them sooner and safely. ProADM’s capacity to detect patients at risk of worsening was less well understood, thus, interventional investigations were required to evaluate its true clinical utility.