Abstract:

AIM: To compare the clinical efficacy of ceftazidime-avibactam (CZA) monotherapy versus combination therapy in critically ill patients with carbapenem-resistant organism (CRO) infections and to identify risk factors affecting prognosis. METHODS: A total of 96 patients with CRO infections who were hospitalized at Zhongda Hospital Southeast University from 1 September 2019 to 31 December 2023 were enrolled. Based on the treatment regimens, patients were divided into monotherapy group (n=59) and combination therapy group (n=37). Propensity score matching (PSM) was applied to balance baseline characteristics between the two groups. The primary outcomes included 30-day all-cause mortality and 30-day clinical cure rate. Secondary outcomes included 14-day all-cause mortality, microbiological clearance rate, total hospital length of stay (LOS), intensive care unit (ICU) LOS, and duration of mechanical ventilation. RESULTS: After PSM, a total of 74 patients were included, with 37 cases in each group. Before PSM, the 30-day all-cause mortality was 35.6% in the monotherapy group and 21.6% in the combination therapy group; after PSM, the rates were 40.5% and 21.6%, respectively. The differences were not statistically significant before and after matching (P=0.147, P=0.079). The 30-day clinical cure rate was 62.7% in the monotherapy group and 73.0% in the combination therapy group before PSM, 56.8% and 73.0% respectively after PSM, with no statistically significant differences before and after matching (P=0.299, P=0.144). However, the microbiological clearance rate was significantly higher in the combination therapy group compared to the monotherapy group (70.3% vs. 49.2%, P=0.042), and the result remained stable after PSM (P=0.010). There were no significant differences in 14-day all-cause mortality, total hospital LOS, ICU LOS, or duration of mechanical ventilation between the two groups (P>0.05). Multivariate logistic regression analysis showed that the use of vasopressors and advanced age were independent risk factors for increased 30-day all-cause mortality. Advanced age, longer time from the positive culture to antibiotic administration, and diabetes were independent risk factors for reduced microbiological clearance, while combination therapy was a significant favorable factor in improving microbiological clearance (P<0.05). CONCLUSION: Although the combination therapy regimen did not show a significant advantage in reducing 30-day all-cause mortality or improving 30-day clinical cure rate in patients with CRO infections, it was associated with a higher microbiological clearance rate. The findings of this study provide new clinical evidence for the application of CZA in the management of CRO infections.

Key words: ceftazidime-avibactam, carbapenem-resistant gram-negative organism, critically ill patients