Risk factors of colistin safety according to administration routes: Intravenous and aerosolized colistin.

BACKGROUND: Nephrotoxicity of intravenous (IV) colistin has impeded its clinical use; aerosolized (AS) colistin may be an alternative, but safety data are lacking. Therefore, this study aimed to evaluate the incidence of acute kidney injury (AKI) and risk factors associated with IV and AS colistin administration.

METHODS: A retrospective study was performed in a tertiary referral hospital. Data were collected before and after colistin administration between October 2012 and April 2016. Exclusion criteria were as follows: age less than 18 years, previous colistin administration, concurrent use of IV and AS colistin, dialysis before colistin use, and colistin use for less than 3 days. We compared AKI incidence following administration of IV versus AS colistin and analyzed risk factors for colistin-associated nephrotoxicity.

RESULTS: A total of 464 patients were enrolled (n = 311, IV group; n = 153, AS group). Incidence of AKI was significantly higher in the IV group (IV vs AS, 20.26% vs 7.84%, p-value < 0.001). Duration of colistin use (OR 1.033, 95% CI 1.009-1.058, p-value 0.008) and presence of chronic kidney disease (OR 2.710, 95% CI 1.348-5.448, p-value 0.005) were associated with nephrotoxicity. There were no significant risk factors associated with AS colistin.

CONCLUSIONS: Although AS colistin was not associated with any significant risk factors for nephrotoxicity, duration of colistin use and baseline kidney function may affect AS colistin-associated nephrotoxicity.