Praga M, Hernández E, Herrero J C, Morales E, Revilla Y, Díaz-González R, Rodicio J L
Department of Nephrology, Hospital Universitario 12 de Octubre, Madrid, Spain.
Kidney Int. 2000 Nov;58(5):2111-8. doi: 10.1111/j.1523-1755.2000.00384.x.
Some patients develop proteinuria and progressive renal failure after unilateral nephrectomy, although the majority of patients maintain normal renal function. Reasons to explain this different evolution are not known.
A cross-sectional study was performed in 73 patients who had undergone unilateral nephrectomy 13.6 +/- 8.6 years before. Patients with morphologic abnormalities in the remaining kidney, systemic disorders, or abnormal renal function at the time of nephrectomy were excluded. All of the 73 included patients showed normal renal function and negative proteinuria at nephrectomy. The patient's medical records were reviewed, and clinical and analytical data throughout follow-up were obtained.
Fifty-three out of the 73 patients (group I) showed a normal renal function and negative proteinuria at the cross-sectional study. The remaining 20 patients (group II) showed proteinuria (3.4 +/- 3.1 g/day). The time elapsed between nephrectomy and proteinuria appearance was 10.1 +/- 6.1 years. Thirteen patients of group II had developed renal insufficiency (serum creatinine at the cross-sectional study of 3.9 + 3.2 mg/dL) in addition to proteinuria. The time elapsed between proteinuria appearance and the onset of renal insufficiency was 4.1 +/- 4.3 years. Renal insufficiency showed a slowly progressive course in most of these patients. There were no significant differences between group I and group II patients in age, gender, renal function, or blood pressure at the time of nephrectomy. In contrast, group II patients showed a body mass index (BMI) that was significantly higher than group I at nephrectomy (31.6 +/- 5.6 vs. 24.3 +/- 3.7 kg/m(2), P < 0.001), at cross-sectional study (33.3 +/- 6.6 vs. 25.1 +/- 3.5 kg/m(2), P < 0.001), and throughout follow-up. Among the 14 obese (BMI > 30 kg/m(2)) patients at the time of nephrectomy, 13 (92%) developed proteinuria/renal insufficiency. In contrast, among the 59 patients with BMI < 30 kg/m(2), only 7 (12%) developed these complications (P < 0.001). Kaplan-Meier estimated probability of negative proteinuria and normal renal function 10 years after nephrectomy was 40 and 70%, respectively, in obese patients at nephrectomy. At 20 years after nephrectomy, these percentages were 8 and 35%, respectively. In contrast, in nonobese patients, the probability of negative proteinuria and normal renal function was 93 and 98%, respectively, at 10 years (P < 0.001) and 77 and 91%, respectively, at 20 years (P < 0.001). Multiple logistic regression analysis showed that the risk of developing renal disease was only statistically correlated with BMI at the time of unilateral nephrectomy (odds ratio 1.34, 1.03 to 1.76 CI).
Obese patients are at risk for developing proteinuria and chronic renal failure after unilateral nephrectomy. Regular and long-term follow-up are recommended in these patients.
一些患者在单侧肾切除术后出现蛋白尿和进行性肾衰竭，尽管大多数患者肾功能保持正常。目前尚不清楚导致这种不同转归的原因。
对73例在13.6±8.6年前接受单侧肾切除术的患者进行了一项横断面研究。排除了剩余肾脏存在形态学异常、全身性疾病或肾切除时肾功能异常的患者。纳入研究的73例患者在肾切除时均表现为肾功能正常且蛋白尿阴性。查阅了患者的病历，并获取了整个随访过程中的临床和分析数据。
在横断面研究中，73例患者中的53例（第一组）肾功能正常且蛋白尿阴性。其余20例患者（第二组）出现蛋白尿（3.4±3.1g/天）。肾切除至出现蛋白尿的时间为10.1±6.1年。第二组中有13例患者除蛋白尿外还出现了肾功能不全（横断面研究时血清肌酐为3.9+3.2mg/dL）。出现蛋白尿至肾功能不全发生的时间为4.1±4.3年。大多数这些患者的肾功能不全呈缓慢进展过程。第一组和第二组患者在肾切除时的年龄、性别、肾功能或血压方面无显著差异。相比之下，第二组患者在肾切除时（31.6±5.6 vs. 24.3±3.7kg/m²，P<0.001）、横断面研究时（33.3±6.6 vs. 25.1±3.5kg/m²，P<0.001）以及整个随访过程中的体重指数（BMI）均显著高于第一组。在肾切除时14例肥胖（BMI>30kg/m²）患者中，13例（92%）出现了蛋白尿/肾功能不全。相比之下，在59例BMI<30kg/m²的患者中，只有7例（12%）出现了这些并发症（P<0.001）。Kaplan-Meier估计肾切除时肥胖患者术后10年蛋白尿阴性和肾功能正常的概率分别为40%和70%。肾切除术后20年，这些百分比分别为8%和35%。相比之下，在非肥胖患者中，术后10年蛋白尿阴性和肾功能正常的概率分别为93%和98%（P<0.001），术后20年分别为77%和91%（P<0.001）。多因素逻辑回归分析显示，发生肾脏疾病的风险仅与单侧肾切除时的BMI存在统计学相关性（比值比1.34，95%置信区间1.03至1.76）。
肥胖患者在单侧肾切除术后有发生蛋白尿和慢性肾衰竭的风险。建议对这些患者进行定期和长期随访。
