Real-World Effectiveness of Ceftazidime-Avibactam for Multidrug-Resistant Gram-Negative Pneumonia, Time-Stratified Risk Factors for Short- and Long-Term Mortality, and Inpatient Costs: A Multicenter Retrospective Cohort Study.

introductionMultidrug-resistant (MDR) Gram-negative pneumonia is associated with high mortality and substantial healthcare resource utilization. Ceftazidime-avibactam (CAZ-AVI) is an important option, yet real-world experience in Chinese pneumonia cohorts is limited and the associated inpatient costs are seldom reported. This study aimed to describe the clinical response to CAZ-AVI in routine practice, to identify the factors associated with 14-day and with 30-day all-cause mortality separately so as to examine how they differ over time, and to characterize inpatient costs.

methodsWe retrospectively studied 693 adults with MDR pneumonia who received at least 3 days of CAZ-AVI at eight hospitals in Hubei, China, between August 2022 and August 2025. Factors associated with 14-day and 30-day all-cause mortality were examined by univariable and multivariable logistic regression, with LASSO-penalized regression and cross-validation as a sensitivity analysis. Acute kidney injury (AKI) was recorded as a safety observation, and pneumonia-related inpatient costs were summarized descriptively. The study is reported in line with Strengthening the Reporting of Observational Studies in Epidemiology (STROBE).

resultsOverall, 480 patients (69.3%) had a favorable response (cure, 356 [51.4%]; improvement, 124 [17.9%]). A higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score was independently associated with mortality at both 14 days (adjusted OR 1.20; 95% CI 1.14-1.26) and 30 days (1.27; 1.18-1.37). At 14 days, death was further associated with bacteremia (4.76; 2.39-9.66), carbapenem-resistant organisms (CRO; 5.93; 2.60-13.60), and septic shock (3.30; 1.32-8.39). At 30 days, the associated factors were Klebsiella pneumoniae (15.19; 3.25-78.94; the wide confidence interval warrants caution) and septic shock (5.74; 1.34-24.97), while a later rise in serum albumin accompanied lower mortality (0.89; 0.82-0.95). AKI occurred in 15 of 693 patients (2.2%). The median total inpatient cost was USD 14,982 (IQR 8462-25,136), of which CAZ-AVI accounted for a median of USD 3901 (IQR 2069-6159).

conclusionIn routine practice, CAZ-AVI for MDR pneumonia was associated with a favorable response, and the factors linked to early death differed from those linked to later death. These associations are hypothesis-generating; together with the cost description, they may help inform time-stratified management and the controlled studies needed to confirm these findings.