Predicting a fatal outcome in patients with pneumonia caused by carbapenem-resistant Klebsiella pneumoniae by hematological indices

Aim. To determine the most significant indicators for predicting a fatal outcome in patients with pneumonia caused by carbapenem-resistant K. pneumoniae.

Materials and мethods. A total of 114 cases of pneumonia caused by K. pneumoniae, including those associated with COVID-19, were retrospectively analyzed. Depending on the outcome of the disease, two groups were formed: group 1 included 54 patients discharged from the hospital upon completion of treatment; group 2 encompassed 60 patients with an unfavorable (fatal) outcome. Patients who did not have a concomitant COVID-19 infection were analyzed separately. The profile of concomitant diseases, hemogram parameters, C-reactive protein (CRP) level, and hematological indices (neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR)) were studied, and the risk of death according to the CURB-65 score was assessed.

Results. Patients with an unfavorable outcome were characterized by higher leukocyte and neutrophil counts, higher NLR, MLR, PLR, and CRP levels, higher risk according to the CURB-65 score, and lower lymphocyte and platelet concentrations. According to the results of the ROC analysis, the most significant prognostic indicators of an unfavorable outcome were lymphocytes, neutrophils, NLR, CURB-65, CRP, and TLR. The diagnostic value of the CURB-65 score (3–5 points) in predicting the risk of an unfavorable outcome was the following: test sensitive ity was 47.5%, specificity was 98.2%, positive predictive value was 96.6%, negative predictive value was 63.1%, accuracy was 71.7%. For NLR (at a threshold value > 6), sensitivity was 85.0%, specificity was 87.0%, positive predictive value was 87.9%, negative predictive value was 83.9%, accuracy was 86.0%. For MLR, the diagnostic accuracy was 79.0%, and for PLR – 73.7%.

Conclusion. The parameter of choice that can be used at the early stage to predict the fatal outcome of pneumonia caused by carbapenem-resistant K. pneumoniae should be NLR (> 6) due to its high sensitivity (85%) and specificity (87%) and ease of use. In addition, the CURB-65 score can be used at NLR > 3. 

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