Abstract
Postoperative complications are a leading cause of morbidity and mortality among elderly patients, largely due to age-related physiological decline, increased comorbidities, and heightened susceptibility to infection. Procalcitonin (PCT), a peptide biomarker associated with systemic bacterial infection, has gained recognition for its diagnostic relevance in critical care and infectious disease settings. While PCT has shown promise in identifying sepsis and guiding antimicrobial therapy, its utility in surgical contexts, especially within geriatric populations, remains incompletely defined. This review aims to evaluate the predictive capacity of perioperative PCT measurements in estimating 30-day mortality and infection-related outcomes in elderly surgical patients, offering insight into its potential role in perioperative risk stratification and management. A systematic review was conducted using 11 studies involving patients aged 65 years and older who underwent cardiac, orthopaedic, thoracic, abdominal, or general surgery. Eligible studies were selected based on their evaluation of serum PCT levels measured perioperatively and the documented association with either 30-day postoperative mortality or infectious complications. Key parameters, such as study design, patient demographics, timing of PCT measurement, biomarker thresholds, and outcome definitions, were extracted. A narrative synthesis was performed, supplemented by pooled analysis of PCT kinetic trends to identify consistent patterns across clinical scenarios. Serial PCT measurements were consistently elevated in patients who developed postoperative infections, with values ranging from 0.69 to 1.16 ng/mL between days 3 and 8 post-surgery, compared to 0.03 to 0.18 ng/mL in non-infected controls (p < 0.001). Most infected patients showed peak levels within 48-72 hours postoperatively, while non-infected individuals exhibited transient elevations that resolved within the same period. Although four studies demonstrated significant associations between elevated PCT and early mortality, particularly when levels exceeded 0.8 ng/mL, the predictive value was inconsistent across other datasets. Mortality prediction improved when PCT was interpreted alongside clinical scoring systems such as multiple organ dysfunction syndrome (MODS) or systemic inflammatory response syndrome (SIRS), highlighting the benefit of multimodal assessment. PCT is a valuable biomarker for identifying postoperative infections in elderly surgical patients, particularly when measured in serial intervals and contextualised with clinical parameters. Its dynamic profile allows for early identification of infectious complications and supports timely intervention strategies. However, PCT's role in mortality prediction is less consistent when used in isolation, showing improved reliability when integrated with systemic assessment tools. Standardised protocols and large-scale multicenter studies are needed to validate its prognostic application and optimise perioperative surveillance in high-risk geriatric cohorts.