[Assessment of long-term renal function after nephrectomy. Study of 53 patients]

Patients with unilateral nephrectomy maintain the remaining kidney function over time, as it has been described in healthy kidney donors.

We performed a cross-sectional study of 53 patients who were followed 5 or more years after nephrectomy. Serum creatinine, BUN, Glomerular Filtration Rate (GFR) (24 hours urine collection and Cockcroft formula), microalbuminuria, proteinuria, Body Mass Index and the annual loss rate of renal function were measured or calculated over the follow-up period. We retrospectively considered the presence of risk factors like diabetes, hypertension, microalbuminuria, dyslipemia, smoking habit, obesity and ACE inhibitors or angiotensin-receptor antagonists treatment. We divided our patients into two groups: group I (normal or mild renal failure: GFR > 50 cc/min and or serum creatinine < 1.4 mg/dL) and group II (moderate or severe renal failure).

The main cause of nephrectomy was renal tuberculosis, followed by lithiasis and pyonephrosis. In addition, 7.5% of patients were kidney donors. At the time of study, 22.7% had diabetes, 60.4% hypertension and 39.6% were obese. The mean age was 60 years (37 years at the moment of nephrectomy). The GFR final mean was 53.6 cc/min (58.8 cc/min by Cockcroft formula). The mean renal function loss rate was 1 cc/min/year. 35% of the patients had moderate or severe kidney failure and were included in group II; 32% had proteinuria and 56.6% had abnormal microalbuminuria. The univariate risk factors analysis for the development of renal failure showed inter-group statistical significative differences in current age, nephrectomy age, microalbuminuria, proteinuria, and hypertension prevalence (p = 0.008). With regard to the progression rate, we found a significant correlation with final microalbuminuria (r = 0.358, p = 0.03). Current age and final proteinuria were found to be significant risk factors in the multivariate analysis.

A high prevalence of renal insufficiency was found among patients with unilateral nephrectomy, which is mainly related to age and proteinuria. The renal function loss rate is slow and is influenced by microalbuminuria.