Comparison of renal function tests of intensive care unit patients using polymyxin or colistin

Infectious diseases are an important cause of mortality and morbidity in patients hospitalized in Intensive Care Units (ICU). Bacterial resistance to antibiotics also contributes to this condition. Polymyxin B and colistin are old antibiotics with a lipopeptide structure, the use of which has been reduced due to their nephrotoxic and neurotoxic side effects, but has found a new place in the clinic due to their effectiveness against MDR microorganisms. The drug with comparable therapeutic efficacy and lower nephrotoxic potential between polymyxin B and colistin would be preferred over the other. There is currently no clinical trial with sufficient statistical power specifically designed to compare the potential for developing AKI during treatment in ICU patients with various comorbidities. In our study, patients who were hospitalized in the Internal Medicine Intensive Care Unit and Anesthesiology and Reanimation Intensive Care Unit at Tekirdağ Namık Kemal University Research Hospital between January 1, 2017 and November 1, 2022 were included. We aimed to compare renal function tests and AKI development rates by retrospectively evaluating patients between the ages of 18-80 who were administered colistin or polymyxin B. A total of 158 ICU patients who received antibiotic therapy for at least 7 days were included in our study. Kidney function tests of these patients during the treatment, AKI development rates according to the KDIGO AKI guideline, AKI stages if developed, duration of AKI formation, and mortality status were examined. As a result, in our study, it was observed that the development of AKI in patients administered colistin was statistically significantly more frequent than in patients administered polymyxin B (p=0.008). By examining on which days AKI developed in patients who developed AKI; they are divided into 3 classes: those that develop in the 24th hour, those that develop in the 48th hour, and those that develop in the first 7 days. While there was no statistically significant difference between the patients treated with colistin and polymyxin B in terms of the development of AKI at the 24th hour and in the first 7 days, a statistically significant difference was detected between the patients treated with colistin and polymyxin B in terms of the development of AKI at the 48th hour (p=0.041). It was observed that patients who developed AKI had a significantly higher mortality than patients who did not develop AKI (p=0.034). No statistically significant difference was detected between the mortality rates in patients who were administered polymyxin B or colistin and developed AKI (p=0.930).