Comparing ceftazidime/avibactam and polymyxin B for treating carbapenem-resistant organisms infections: A propensity score-matched retrospective cohort study.

BACKGROUND AND AIM: There are limited comparative studies of ceftazidime/avibactam (CAZ/AVI) vs. polymyxin B (PMB) for carbapenem-resistant organisms (CRO) infections. The aim of this study was to compare the efficacy and safety of CAZ/AVI and PMB in treating CRO infections.

METHODS

This single-centre, retrospective cohort study with propensity score-matching (PSM) involved adult patients with CRO infections. Patients who received the CAZ/AVI-based regimen were included in the cohort group; those prescribed with the PMB-based regimen were included in the control group. The primary outcome was 28-day all-cause mortality.

RESULTS

Among 298 eligible patients, 96 patients in each group were included in the PSM cohort. The CAZ/AVI group showed no improvement in 28-day or 14-day all-cause mortality, nor in 14-day clinical response, compared to the PMB group. However, the CAZ/AVI-based regimen was associated with higher 14-day clinical response rates than the PMB-based regimen in subgroups with carbapenem-resistant Pseudomonas aeruginosa (CRPA) infections and monotherapy. The CAZ/AVI group achieved greater CRO eradication than the PMB group (crude odds ratio [OR], 1.658; 95% confidence interval [CI], 1.108-2.480; P = 0.014; adjusted OR, 1.718; 95% CI, 1.055-2.798; P = 0.030). This advantage in CRO eradication with CAZ/AVI was consistent in most subgroups, including septic shock, bloodstream infection and lower respiratory tract infection. The CAZ/AVI and PMB groups had comparable nephrotoxicity (crude OR, 0.577; 95% CI, 0.306-1.089; P = 0.090; adjusted OR, 0.741; 95% CI, 0.361-1.521; P = 0.414).

CONCLUSION

CAZ/AVI-based and PMB-based regimens demonstrated similar clinical efficacy and nephrotoxicity in treating CRO infections. However, CAZ/AVI was superior to PMB in CRO eradication and treating CRPA infections. CAZ/AVI monotherapy was more effective than PMB monotherapy for CRO infections.

TRIAL REGISTRATION: ChiCTR2300078790 prospectively registered on 19 Dec 2023 (https://www.chictr.org.cn).