The Urine Albumin-to-Creatinine Ratio and Kidney Function after Nephrectomy

Abstract

Purpose: Patients with kidney cancer are at risk for chronic kidney disease after radical and partial nephrectomy. We determined if the urine albumin-to-creatinine ratio is independently associated with progressive chronic kidney disease after nephrectomy.

Materials and methods: We performed a cohort study based within a large, integrated health care system. We identified patients who underwent radical or partial nephrectomy from 2004 to 2014 with urine albumin-to-creatinine ratio measured in the 12 months before surgery. We fit multivariable models to determine if the urine albumin-to-creatinine ratio was associated with the time to chronic kidney disease progression (defined as reaching stage 4 or 5 chronic kidney disease, estimated glomerular filtration rate less than 30 ml/minute/1.73 m²). We performed a parallel analysis measuring the time to stage 3b, 4 or 5 chronic kidney disease (estimated glomerular filtration rate less than 45 ml/minute/1.73 m²) among patients with normal or near normal preoperative kidney function (estimated glomerular filtration rate 60 ml/minute/1.73 m² or greater). We also examined the association between urine albumin-to-creatinine ratio and survival.

Results: A total of 1,930 patients underwent radical or partial nephrectomy and had preoperative urine albumin-to-creatinine ratio and preoperative and postoperative estimated glomerular filtration rate. Of these patients 658 (34%) and 157 (8%) had moderate (urine albumin-to-creatinine ratio 30 to 300 mg/gm) or severe albuminuria (urine albumin-to-creatinine ratio greater than 300 mg/gm), respectively. Albuminuria severity was independently associated with progressive chronic kidney disease after radical (moderate albuminuria HR 1.7, 95% CI 1.4-2.2; severe albuminuria HR 2.3, 95% CI 1.7-3.1) and partial nephrectomy (moderate albuminuria HR 1.8, 95% CI 1.2-2.7; severe albuminuria HR 4.3, 95% CI 2.7-7.0). Albuminuria was also associated with survival following radical and partial nephrectomy.

Conclusions: In patients undergoing radical or partial nephrectomy the severity of albuminuria can stratify risk of progressive chronic kidney disease.

Keywords: carcinoma; kidney neoplasms; proteinuria; renal cell.