Reduced kidney size in adult offspring of Balkan endemic nephropathy patients and controls: a prospective study

Abstract

Introduction: Reduced kidney size has been proposed as a criterion for clinical diagnosis of Balkan endemic nephropathy (BEN). Some studies suggest that smaller kidneys are found in advanced stages of BEN, whereas others reported them in earlier stages. To investigate the clinical course of kidney sizes in the offspring of BEN and non-BEN parents, we followed up a cohort of adult offspring over 5 years. We hypothesized that parental history affects kidney dimensions.

Methods: Four repeated ultrasound measurements of kidney length and cortex width were conducted in 121 offspring of BEN and 98 offspring of non-BEN parents. Repeated measurements were analyzed using mixed models adjusting for gender and time-dependent information on other kidney diseases, diabetes, age, height and year of follow-up.

Results: A reduction of kidney length was associated with maternal BEN (-4 mm, P = 0.001). We detected a parallel decline in kidney length in the various offspring groups. However, kidney cortex width was significantly smaller when both parents or the mother had BEN and offspring age > or =60 years (-1.88 mm, P = 0.0003; -1.03 mm, P = 0.05). In the 5th year of follow-up, 37 participants developed BEN (14 confirmed, 23 suspected). Kidney cortex width at baseline was smaller in offspring who developed BEN (P = 0.0001).

Conclusions: The development of kidney dimensions depends on the parental BEN status and offspring age. In BEN offspring, ultrasound measurements of the kidney cortex width seem to have a prognostic value.