Avaliação diagnóstica e prognóstica dos níveis plasmáticos de procalcitonina, proteína c reativa e copeptina na infecção bacteriana secundária em pacientes com Covid-19 internados em unidade de terapia intensiva

Abstract

Introduction: Secondary bacterial infection is the main cause of death in patients with severe COVID-19 admitted to the intensive care unit (ICU), especially in those undergoing invasive mechanical ventilation. Identifying these infections is challenging, as clinical, laboratory, and imaging manifestations can overlap with those caused by SARS-CoV-2. The usefulness of biomarkers such as C-reactive protein (CRP), procalcitonin (PCT) and copeptin for identifying bacterial infection in patients with severe COVID-19 is not well established. Objective: To evaluate the role of circulating levels of PCT, CRP and copeptin in identifying secondary bacterial infection in patients with COVID-19 admitted to the ICU, as well as the association of these molecules with the prognosis of these individuals. Methods: Observational, prospective study conducted in the ICU of a university hospital in Belo Horizonte, MG, from April/2020 to May/2021. Adult patients (≥ 18 years old) with a confirmed diagnosis of COVID 19 were included. Serum CRP, PCT and copeptin were measured on admission (D1), on the third (D3) and seventh (D7) days of ICU stay. Patients were divided into two groups: with and without healthcare-associated infection (HAI) by bacteria, whose occurrence was defined by the assistant team. Results: We included 86 patients, with a median age of 62 years (45 - 71). Forty-six patients (54%) had HAI (median 7 days after inclusion), of which 71,7% were confirmed by microbiological culture. Ninety percent of patients had comorbidities, with emphasis on systemic arterial hypertension (64%), diabetes mellitus (41.9%) and obesity (24.4%). Most used invasive mechanical ventilation (70.9%), vasopressors (69.8%) and underwent hemodialysis (85.9%). The HAI subgroup had a significantly higher SOFA score (Sequential Organ Failure Assessment) than the group without HAI in the three evaluation periods D1 6 (4 – 9) vs 4 (2 – 8), p=0.007; D3 7 (4 – 9) vs 4 (3 – 7), p<0.003; and D7 7 (5 – 10) vs 4 (3 – 7), p=0.005. Even though significantly higher serum levels of CRP (D7), PCT (D7) and copeptin (D3 and D7) were observed in the subgroup with HAI in the bivariate analysis, these differences did not remain in the analysis adjusted for the severity and presence of comorbidities. Only the SOFA score was independently associated with the occurrence of HAI, on D3 = OR, 1,197; 95% CI (1.033 - 1.387), p= 0.017; and at D7= OR, 1.261; 95% CI (1.034 - 1.536), p=0.022). Patients with HAI had longer ICU stays (17 [10-29] vs 7.5 [3-10] days, p <0.001) and hospital stays (25 [12-43] vs 13 [7 - 20] days, p=0.001), as well as higher hospital mortality (73.9% vs 32.5%, p<0.001). Serum copeptin levels were significantly higher among patients who died during hospitalization, with moderate accuracy (68.5%) for this outcome, considering the cutoff point of 22.0 pmol/L. Conclusion: PCT, CRP and copeptin dosages, although higher in the group of patients with COVID-19 who developed HAI, failed to distinguish patients with and without this complication, apparently being more associated with clinical severity and mortality.