Abstract
Aim
To compare outcomes and incidence of adverse events (AE) of colistin versus tigecycline for treatment of patients with carbapenem-resistant Acinetobacter baumannii (CRAB) osteomyelitis.
Method
Retrospective study. Records of 111 patients with microbiologically confirmed CRAB osteomyelitis were analyzed. Colistin (34 cases) and tigecycline (31 cases) were the main drugs used for treatment of extremely-drug resistant (XDR) isolates. Patients who received these two antimicrobials were compared according to baseline features (sex, age, length of hospital stay, Charlson index, presence of comorbidities or immunosuppression, previous renal disease, smoking, alcoholism or use of illicit drugs, previous orthopedic surgery on affected limb, topography of infection, classification of osteomyelitis, ASA score, infection related to pressure ulcer or neuropathic foot, presence of implant, need for soft tissue repair or negative pressure therapy and previous antimicrobial use), clinical outcome after 12 months of treatment (remission of infection was considered the favorable outcome; recurrence of infection, amputation and death were considered unfavorable outcomes; loss of follow-up was analyzed separately) and AE during treatment (impaired renal function; liver abnormalities; nausea; skin rash; neurological abnormalities and other events in general). Quantitative variables were described using summary measures and compared using Student's t or Mann-Whitney tests. Qualitative characteristics were described with absolute and relative frequencies and compared using chi-square or exact tests (Fisher's exact or likelihood ratio test).
Results
Regarding baseline characteristics, proportion of male patients was higher in the group treated with colistin (p = 0.028). In the group treated with tigecycline, there was a significant predominance of smokers (p = 0.021) and patients with chronic osteomyelitis (p = 0.036). Regarding clinical outcomes after 12 months of treatment, there was no difference between groups. Overall incidence of AE was significantly higher among patients treated with colistin (p=0,047), as well as renal impairment (p = 0.003). Incidence of nausea was higher in patients treated with tigecycline (p = 0.046), but there was no difference between groups in relation to altered liver enzymes and other events.
Conclusions
In this retrospective analysis, there was no significant difference between clinical outcomes of patients with CRAB osteomyelitis treated with colistin compared to tigecycline. Although the occurrence of nausea was greater in the group receiving tigecycline, this antimicrobial appeared to have a better safety profile for treatment of osteomyelitis related to XDR A. baumannii.
