The kidney in acromegaly: renal structure and function in patients with acromegaly during active disease and 1 year after disease remission.

ABSTRACT

BACKGROUND: The GH/insulin-like growth factor 1 axis is physiologically involved in the regulation of electrolytes and water homeostasis by kidneys, and influences glomerular filtration and tubular re-absorption processes. The aim of the study was to investigate renal structure and function in acromegalic patients during active disease and disease remission. PATIENTS Thirty acromegalic patients (15 males and 15 females), aged 32-70 years, were enrolled for the study. Ten de novo patients had active disease, whereas 20 patients showed disease remission 1 year after medical treatment with somatostatin analogs (SA) (ten patients) or surgery (ten patients). Thirty healthy subjects matched for age, gender, and body surface area were enrolled as controls. RESULTS: In both active (A) and controlled (C) patients, creatinine clearance (P<0.001) and citrate (P<0.05) and oxalate levels (P<0.001) were higher, whereas filtered Na (P<0.001) and K (P<0.001) fractional excretions were lower than those in the controls. Urinary Ca (P<0.001) and Ph (P<0.05) levels were significantly increased compared with the controls, and in patients with disease control, urinary Ca (P<0.001) levels were significantly reduced compared with active patients. Microalbuminuria was significantly increased in active patients (P<0.05) compared with controlled patients and healthy control subjects. The longitudinal (P<0.05) and transverse (P<0.05) diameters of kidneys were significantly higher than those in the controls. In all patients, the prevalence of micronephrolithiasis was higher than that in the controls (P<0.001), and was significantly correlated to disease duration (r=0.871, P<0.001) and hydroxyproline values (r=0.639, P<0.001). CONCLUSIONS: The results of the current study demonstrated that acromegaly affects both renal structure and function. The observed changes are not completely reversible after disease remission.