Impacto das alterações ponderais na filtração glomerular e proteinúria em doadores renais

Abstract

Introduction: Nephrectomy (Nx) for living kidney donation has been supported by studies that report few long-term clinical implications for donors. But the parameters used for donor evaluation are the same as those used for the general population. Hence, it is necessary to review the adequacy of those values and assess obese donors, since the incidence of obesity is increasing worldwide. Objective: To evaluate the impact of the ponderal changes and the values used as references for normal renal function of kidney donors. Methods: The study is a series of cases, with 48 living kidney donors who underwent uninefrectomy, between 1983 and 2006. Anthropometric data, systemic arterial pressure, glomerular filtration rate estimated (eGFR) by creatinine clearance and 24h proteinuria were assessed. Results: 52.08% of the sample showed eGFR between 60 and 89 ml/min and only 4.2% presented eGFR ≥ 120ml/min. It can be inferred that 77.1% were subject to hyperfiltration, if we consider as the normal value for a single kidney 50% of 120 ml/min, used for the population with two kidneys. Proteinuria was observed in 22.9% of the sample and, using the same reasoning as above and taking as reference 75mg/24h, 64.6% showed high levels of proteinuria. At the time of Nx, 10.4% of the sample was obese and has evolved with the increase of the obesity rate to 31.3%. The group also showed an increase in mean BMI. Obese patients had higher values of eGFR and systolic arterial pressure. Individuals with higher levels of proteinuria also showed higher ponderal values. Conclusion: Using the values of eGFR and proteinuria for the single kidney, hyperfiltration and proteinuria were, respectively, 18.3 and 2.8 times higher when compared to rates obtained by using the parameters applied for the general population. After donation, it was found an increase of body mass index (BMI) and obesity in the sample. Therefore, obesity appears to be associated with higher hyperfiltration, systolic arterial hypertension and subsequent proteinuria. Those findings justify a strict ponderal control for that population in order to avoid an overlapping of factors leading to renal injury.