الفهرس 
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Abstract
Sepsis continues to have a high rate of morbidity and death, according to recent research conducted globally. According to these studies, more than 30 million individuals worldwide suffer from sepsis each year. Sepsis affects 1%-2% of hospital inpatients each year. Roughly 15% of these patients will develop septic shock, which happens in 10% of ICU admissions with a death rate of 50%. A retrospective study that included 419 sepsis patients revealed that the mortality rate for patients in the ICU of their teaching hospital was as high as 43.9%. According to an epidemiological survey conducted in China, patients with sepsis had a mortality rate of 48.7% (Kabra et al., 2023).
The word “sepsis” is derived from the ancient Greek word for rotten flesh and putrefaction. Since then, a wide variety of definitions have been applied to sepsis, including sepsis syndrome, severe sepsis, bacteremia, septicemia, and septic shock. In 1991, the American College of Chest Physicians (ACCP) and the Society of Critical Care Medicine (SCCM) developed a new set of terms and definitions to define sepsis in a more “precise manner” (Skrupky et al., 2011).
Lactic acid is conventionally known as the substance generated in skeletal muscles after rigorous exercise, producing a state of muscular cramps and fatigue. As our understanding of the physiologic processes in our body has advanced, it is being realized that lactic acid plays a much more integral role in the maintenance of homeostasis, as well as in the pathogenesis of some common but deadly conditions such as carcinomas. In the human body, lactic acid or lactate, is derived from skeletal muscle (25%), skin (25%), brain (25%), red blood cells (20%), and intestine (10%) (Sun et al., 2017).
Lactic acid as a prognostic marker for septic patients serves suitably well. In patients who have not yet progressed to shock, lactate levels of more than 4 mmol/L are 96% specific in predicting mortality (Jaiswal et al., 2022). It also has the advantage of foreshadowing hyoperfusion, when clinical signs such as a fall in blood pressure have not appeared. As the levels of lactate increase, a proportional increase in mortality is also noted, as seen in the study by Shapiro et al. Levels of ≥ 4 mmol/L had a mortality of 28.4%, (Khater et al., 2016).
In adult humans, albumin is the most abundant plasma protein with a concentration ranging from 35 to 50 g/L. Albumin represents 50% of the total protein content of plasma, with globulins making up most of the rest. It is a single peptide chain of 585 amino acids in a globular structure.
Associations of serum albumin levels with development and severity of infectious diseases may be sufficiently explained by the effects of systemic inflammation on albumin kinetics making low serum albumin levels a surrogate marker. If low serum albumin levels can be shown to directly affect innate immunity and antimicrobial defense, associations with infectious diseases might also lead to the identification of low albumin mass as culprit, causally contributing to both acquisition and development of complications of infections (Aranda-Michel et al., 2019).
In sepsis, acute and chronic states of low serum albumin are independently associated with increased risk of mortality. Sepsis is a common cause of mortality in ICUs, and low serum albumin levels in the acute phase are associated with increased risks of severity and death in patients who develop severe sepsis and organ failure (Permpikul et al., 2021).
Our study aimed to evaluate the prognostic value of the L/A ratio compared to lactate level for predicting sepsis-related 28 days mortality in patients admitted to ICU.
The results of our study have shown that the L/A ratio has better prognostic performance for predicting in-hospital mortality in septic patients. When looking at only the septic shock population, the L/A ratio also outperformed lactate alone (AUC 0.645 vs 0.617). Improved prognostic accuracy was consistent across subgroups of lactate levels (lactate <2 mmol/L and lactate ≥2 mmol/L), hypoalbuminemia (albumin <3 g/dL) and renal dysfunction. Additionally, the L/A ratio was an independent predictor of mortality (OR 2.53, p < 0.001). Our study supports existing literature on the use of the L/A ratio as a prognostic marker in patients with sepsis with fair discriminative value. Although lactate is a well-studied prognostic biomarker, its interpretation is complex due to the pathophysiology that can lead to serum lactate elevations. Moreover, normal lactate levels may be falsely misinterpreted as a good prognosis in high-risk patients. As such, the incorporation of albumin as a reflection of nutritional status in the L/A ratio increases its use in prognostication of sepsis patients (Bou Chebl et al., 2020).
In our study The specificity of L/A ratio in predicting death is 56.3, whereas the specificity of lactate alone in predicting death is 68.8 and the specificity of albumin alone in predicting death is 37.5. Also, the sensitivity of L/A ratio, lactate, and albumin in predicting the outcome is 76.5, 52.9, and 70.6, respectively.
We found that albumin <2.3 g/dL, lactate ≥2 mmol/L, and L/A ratio predict mortality. The diagnostic accuracy of the L/A ratio was excellent in predicting mortality among sepsis subjects as compared to lactate and albumin alone. A cutoff of L/A ratio 0.89 has a sensitivity of 76.5and a specificity of 56.3% in predicting death. Calculating the L/A ratio in sepsis patients on admission can help in aggressive management and prevent mortality and morbidity. Easy availability and early results of the L/A ratio can help in assessing and predicting the outcome.