What is the Best Predictor for Vancomycin Nephrotoxicity?
Methods: This is a retrospective, observational cohort study of adult patients who received vancomycin for ≥ 72 hours at the University of Kansas Medical Center between 9/7/2011 and 2/7/2012. The study included both inpatient and outpatient data. NT was defined as: ≥ 50% or ≥ 0.5 mg/dl increase in serum creatinine from baseline on 2 consecutive measurements. Data collected included 3 main predictors: average VT, first VT, VT preceding acute renal failure (VTPARF) and other possible risk factors for NT. We divided the patients into 4 groups (1 to 4): [VT < 10 µg/ml, 10 µg/ml ≤ VT < 15 µg/ml (reference group), 15 µg/ml ≤ VT ≤ 20 µg/ml and VT > 20 µg/ml]. We analyzed the data using average VT and first VT. We also compared the VTPARF to the average VT in patients with no ARF.
Results: The study included 474 patients, 63/474 developed ARF (13.29%). The incidence of ARF in groups (1-4) was: 2/114 (1.75%), 9/180 (5%), 31/122 (25.4%) and 21/49 (42.85%) using the average VT. It was: 17/194 (8.76%), 22/155 (14.19%), 10/66 (15.15%) and 14/42 (33.33%) using the first VT. Compared to reference group (2), ARF incidence was significantly higher in group 3 (p-value = 0.0001), group 4 (p-value = 0.001) by average VT and only in group 4 (p-value = 0.014) by first VT. Among patients with ARF 30/62 (48.39%) had VTPARF ≥ 15 µg/ml versus 119/411 (28.95%) of patients with no acute renal failure using the average VT (p-value = 0.004). ARF incidence was associated with baseline Cr ≥ 1.5 mg/dl (p-value = 0.03). There was a tendency toward increased nephrotoxicity in patients with morbid obesity (p-value = 0.056). There was no observed association with other possible risk factors for NT.
Conclusion: Average VT ≥ 15 µg/ml and first VT > 20 µg/ml are associated with increased NT. Patients with acute renal failure had significantly more VTPARF ≥ 15 µg/ml compared to patients with no ARF (average VT). This study suggests that VT ≥ 15 µg/ml is likely more nephrotoxic than lower levels. The only concomitant risk factor that was associated with NT was baseline Cr ≥ 1.5 mg/dl.
W. Haidar, None
M. Brimacombe, None
W. El Atrouni, None