Neuropathy is a major contributing factor to diabetic erectile dysfunction

Erectile dysfunction (ED) in diabetes is multifactorial. So far, the impact of neuropathy has not been well determined. This study was performed to as sess the frequency of abnormal neurophysiological tests in patients with ED due to diabetes compared to patients with ED due to nondiabetic neuropathi es, in order to estimate the contribution of neuropathy in diabetic ED. For ty-nine men with ED were studied. We classified ED as 'diabetic', 'neuropat hic' or 'ED of other origin'. 26.6% of the men fulfilled the criteria of di abetic ED, 42.9% had neuropathic ED. In every patient history taking, a que stionnaire focusing on autonomic symptoms other than ED, clinical examinati on, nerve conduction studies (NCS), sphincter ani electromyography (EMC), h eart rate variability testing HRV) and quantitative sensory testing (QST) w as performed. Vascular function was assessed by the intracavernosal prostag landin E1 (PGE1) injection test. The frequency of abnormal results in diabe tic and neuropathic patients was compared. Vascular function was abnormal i n only one patient with diabetic ED and three patients with neuropathic ED. Both groups had similar frequencies of autonomic symptoms other than ED (6 4% in diabetic vs. 64% in neuropathic patients), abnormal EMG (33% vs. 40%) and abnormal QST (vibratory perception 83% vs. 84%, cold perception 9% vs. 19%, warm perception 42% vs. 43%). Abnormal clinical findings (50% vs. 33% ), NCS (75% vs. 50%) and HRV (39% vs. 25%) were slightly, but not significa ntly more frequent in men with diabetic ED than neuropathic ED. The tests i ndicating neuropathy showed abnormalities in men with diabetic ED as freque ntly as in men with neuropathic ED. Some tests even suggested neuropathy mo re often in diabetic than in neuropathic ED. The findings support the hypot hesis that neuropathy contributes significantly to the pathophysiology of E D in diabetes mellitus.