Optimal dosing interval of intravenous Colistin monotherapy versus combination therapy: A systematic review and meta-analysis

We aimed to maximize the clinical response and effectiveness of colistin antibiotics in patients with multi-drug (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria, there is an increasing interest in colistin combination therapy with other antibiotics and extended interval dosing regimens. This systematic review and meta-analysis aim is to evaluate if the combination therapy is superior to monotherapy with colistin regarding increased survival and also which dose interval is the most effective to utilize. English language, peer-reviewed journal publications from the first date available to 25 January 2022 were identified by searching the PubMed and Web of Science databases. Forest plots for overall and subgroups and funnel plots were graphed. 42 studies were included in the study. Among them, 38 studies were on combination therapy, and four on dose interval. The overall pooled odds ratio is 0.77 (CI: 0.62; 0.95) (p value < 0.017). The I^2 value was 43% (p value < 0.01). The Begg correlation test of funnel plot asymmetry showed no significant publication bias (0.064). The overall pooled odds ratio for Carbapenem is 0.74 (CI: 0.48; 1.13). A prospective randomized controlled trials (RCT) on 40 adults intensive care unit (ICU) patients with ventilator-associated pneumonia (VAP), comparing the mortality and ICU length of stay of 8- or 24- hour intervals regimens, showed that the ICU length of stay and ICU mortality were; 31.31, 35.3 days, and 32.06, 22.2% in groups 24-h interval and 8- hour interval (p value: 0.39, 0.87), respectively. It seems that combination therapy is associated with drug synergism and increased survival. The extended interval colistin administration may result in higher peak concentration and bacterial eradication. In both cases, we face a dearth of literature.