Mortality Rate in Critically Ill Patients Diagnosed with Sepsis: Can Blood Culture Results Predict Mortality?

Abstract

Background: Sepsis remains a major cause of mortality among critically ill patients, and the prognostic value of microbiological culture results in sepsis outcomes remains controversial. Objectives: This study aimed to evaluate differences in mortality between patients with culture-negative and culture-positive sepsis admitted to the intensive care unit (ICU) at Imam Reza Hospital, Tabriz, Iran, and to emphasize the importance of accurate diagnosis and management in hospitalized patients. Methods: This cross-sectional study included 150 patients with sepsis admitted to the general ICUs at Imam Reza Hospital, Tabriz, Iran, over a 6-month period. Demographic characteristics, clinical variables, laboratory parameters, severity scores, culture results, and patient outcomes were collected using a structured checklist. Patients were categorized into culture-positive and culture-negative groups. Univariate and multivariable logistic regression analyses were conducted to identify independent predictors of in-hospital mortality. Results: Of the 150 patients, 86 (57.3%) had positive culture results. Patients with culture-positive sepsis had significantly longer ICU and hospital stays and higher crude hospital mortality than those with culture-negative sepsis (41% vs. 9.7%, P < 0.001). In the univariate analysis, culture-positive sepsis was strongly associated with increased hospital mortality (OR = 7.72; 95% CI, 2.81 - 21.19). However, after adjustment for age, sex, APACHE II score, C-reactive protein level, and diastolic blood pressure, culture positivity was no longer an independent predictor of mortality (adjusted OR = 3.30; 95% CI, 0.93 - 11.69). Increasing age remained independently associated with hospital mortality. Conclusions: Although culture-positive sepsis was associated with worse clinical outcomes and higher unadjusted mortality, it was not an independent predictor of hospital mortality after adjustment for key clinical and severity-related factors. These findings underscore that patient characteristics and illness severity are more important than culture status alone in predicting mortality among critically ill patients with sepsis.