Prognostic value of amino terminal pro-b-type natriuretic peptide in septic patients

Background

Amino terminal pro-B-type natriuretic peptide (NT proBNP) has been demonstrated high in septic patients. Our objective was to analyze the behavior of this biomarker and its prognostic value in a cohort of septic patients admitted to the ICU.

Methods

A prospective cohort study was carried out in septic patients admitted to the ICU. The analyzed variables were demographic characteristics, severity scales, empiric antibiotic treatment, determination of NT proBNP and mortality. A univariate analysis and a multivariate logistic regression on mortality using SPSS 12.0 were conducted.

Results

We included 98 patients, 37% female, age 64 years (standard deviation, 16). The median Acute Physiology and Chronic Health Evaluation II score was 18 (standard deviation, 7) and the median Sepsis-related Organ Failure Assessment score was 7 (standard deviation, 5). Occurrence of medical sepsis was 55%. The most common focus was abdominal (40%), followed by pneumonia (32%) and urine (16%). The ICU mortality was 22.7% and the hospital mortality was 30%. The values of NT proPNB were higher in patients with septic shock (P = 0.001) and with acute kidney failure (creatinine >2 mg/l) (P < 0.001). There was a linear correlation between the values of NT proPNB and creatinine (r² = 0.33, P < 0.001). The values of NT proPNB at admission were significantly higher in patients who died in the ICU (P = 0.027). In the multivariate analysis, the variables significantly associated with mortality were Acute Physiology and Chronic Health Evaluation II score, the female sex, inadequate empiric antibiotic treatment, fungal infection or Gram-positive infection and the presence of mechanical ventilation. In the analysis of those 66 cases with NT proPNB values seriated, the variables independently associated with mortality in the ICU were inadequate empirical antimicrobial treatment, Sepsis-related Organ Failure Assessment score at 24 hours, acute kidney failure and deterioration in the values of NT proPNB.

Conclusion

The admission values for NT proPNB of septic patients in the ICU do not add significant information for prognosis, but are indicators of cardiovascular and renal dysfunction. The worsening of these values during admission appears to be associated with increased mortality in the ICU.