[Study of sexual function in male hemodialysis patients--analysis of the cause of erectile dysfunction]

Erectile dysfunction is a well documented complication among male hemodialysis patients. The cause has been reported to be related to multiple factors, including neurological, endocrinological and vasculogenic elements. The purpose of this study was to identify the factors which most greatly determine erectile dysfunction in hemodialysis patients. Male hemodialysis patients without diabetes mellitus and severe anemia (Hb value < 8.0 g/dl) were entered into the study. We measured nocturnal penile tumescence (NPT) values in these patients and carried out neurological studies (measurement of the penile dorsal nerve conduction velocity and the bulbocavernosus reflex (BCR) latency). a vasculogenic study (measurement of the penile blood pressure index (PBPI) and endocrinological studies (measurement of serum free testosterone levels and serum prolactin levels before hemodialysis). NPT values (maximum penile circumference changes) in hemodialysis patients decreased compared with those in healthy males. In both hemodialysis patients and healthy males, NPT values decreased with age. NPT values in hemodialysis patients were significantly lower than those in healthy males in the fifties and sixties. 32.2% of hemodialysis patients had severe penile neurological disorder. 55.6% of them showed abnormal NPT. PBPI was low in only 10.0% of hemodialysis patients. However, there was a significant correlation between PBPI and the NPT value (r = 0.387). Serum free testosterone levels in hemodialysis patients were significantly lower than those in healthy males. There was a significant correlation between the serum free testosterone level and the NPT value (r = 0.328). However, there was no correlation between the serum prolactin level and the NPT value. To identify the factors which most greatly determine erectile dysfunction in hemodialysis patients, we carried out multivariate analysis. The criterion variables in this analysis were NPT values. The coefficient of determination was highest for a neurological disorder (30.7%), followed by an endocrinological disorder (a reduction in the serum free testosterone level) (11.6%) and a vasculogenic disorder (a reduction in PBPI) (4.2%).