Effect of post-nephrectomy acute kidney injury on renal outcome: a retrospective long-term study

The effects on renal prognosis of acute kidney injury after elective unilateral nephrectomy are ill-defined. We evaluated as whether post-operative acute kidney injury modifies renal outcome over the long term. This is a retrospective study examining all consecutive adult patients referred to three Nephrology Units and that had previously undergone elective unilateral nephrectomy. We evaluated the association of post-nephrectomy acute kidney injury with the combined renal outcome of chronic dialysis requirement, 40% decline in glomerular filtration rate or new-onset severe proteinuria (> 500 mg/24 h). Clinical correlates of acute kidney injury and renal outcome were also examined. 106 patients were enrolled. 52 patients had post-operative acute kidney injury with a median increment of serum creatinine of 0.67 [0.48-0.86] mg/dl; in these patients, serum creatinine and urea increased from the first day post-nephrectomy while contraction of urinary output was found in 7 patients. Older age [OR: 1.72; 95% CI 1.05-2.82; P = 0.030] associated with post-operative acute kidney injury. Over a median follow-up of 8.9 [95% CI 3.1-24.2] years, the combined renal outcome occurred, respectively, in 28 (53.8%) and 14 (25.9%) patients with and without acute kidney injury (P = 0.003). Logistic regression analysis showed that acute kidney injury (OR: 3.22; 95% CI 1.35-7.66; P = 0.008) and male gender (OR: 2.72; 95% CI 1.08-6.85; P = 0.034) were associated with poor renal outcome after adjustment for main comorbidities. In our population of referred patients, acute kidney injury after unilateral nephrectomy was common and associated with progressive chronic kidney disease, especially in older males.