Procalcitonin as a Biomarker and Risk Stratification Tool in COVID-19 Patients

Background: COVID-19 is a systemic disease with a highly variable clinical course, ranging from being asymptomatic to manifestations like bilateral interstitial pneumonia, and multi-organ failure.

Aims & Objectives: To evaluate whether Procalcitonin can act as a biomarker for risk stratification and identify patients at risk for clinical deterioration-critical disease.

Study Design: This was a prospective cohort study.

Place and Duration of Study: Medical High Care & Intensive Care Unit at University Hospital Ayr, UK between January 2021, and March 2021.

Methodology: The patients were classified into two groups, Low Procalcitonin (PCT) group (<0.5 μg/L) and High Procalcitonin (PCT) group (>0.5 μg/L) at 48 hr. of admission to the unit. Primary outcomes compared were requirement of invasive ventilation, multi-organ failure, antibiotic consumption, and mortality. Continuous variables were analyzed using two-sample unpaired t test while categorical variables were compared using Fisher’s exact test. A p-value of <0.05 was considered statistically significant.

Results: A total of 40 COVID-19 patients were included in the study, with 23 patients in the low PCT group and 17 patients were included in the high PCT group. The mean PCT at 48 hrs in the low PCT group was 0.327±0.098 μg/L, whereas in the high PCT group, it was 2.862±1.409 μg/L, the differences being statistically significant (p<0.0001). 56.52% patients(n=13) had multi-organ failure & mortality remained 26.09% in the Low PCT group whereas 94.12% of the patients (n=16) developed multi-organ failure & the mortality was 70.59% in the high PCT group, differences being statistically significant. Also, significant differences were noted in the usage of antibiotics between the two groups.

Conclusion: We concluded that Procalcitonin levels could be used reliably for risk stratification and raised PCT values would help identify a subgroup of COVID-19 patients with increased likelihood of critical disease and poor outcome.