Low serum albumin and the increased risk of amikacin nephrotoxicity

The purpose of the present study was to know the incidence and risk factors associated with amikacin nephrotoxicity in a cohort of patients form a general medial center.

Prospective follow-up of a cohort of 104 patients treated with intravenous amikacin for at least 36 hours. We assessed serum creatinine every other day and amikacin plasma levels at 48 and 96 hours after treatment was begun. Patients with other risk factors to develop acute renal failure were excluded. The study was conducted at the Hospital de Especialidades, Centro Médico de Occidente, Instituto Mexicano del Seguro Social.

Ten patients developed nephrotoxicity (9.6%). According to the logistic regression model, the most powerful predictor of high nephrotoxicity probability was the serum albumin concentration. The lower the serum albumin concentration, the higher the risk of toxicity. The mean serum albumin in the group of patients with nephrotoxicity was 2.6 +/- 0.55 g/dL, while in the group of patients without toxicity it was 3.5 +/- 0.55 g/dL. No differences were observed in the age, sex, diagnosis, renal function and amikacin doses between both groups. Furthermore, low serum albumin concentration was also associated with amikacin accumulation in plasma. The group of patients with hypoalbuminemia (< or = 3.0 g/dL) had a significantly higher trough amikacin plasma level (assessed at 48 and 96 hours of the initiation of treatment) than those with normal serum albumin, with no differences among the age, sex, baseline renal function and received amikacin doses.

We conclude that serum albumin concentration is the most powerful predictor of amikacin nephrotoxicity. The risk factors observed in the present study are similar to those previously observed by us at the Instituto Nacional de la Nutrición Salvador Zubirán.