Previously unrecognized diabetes mellitus in sexually impotent men.

Three-hour oral glucose tolerance tests (GTTs) were performed for 58 men with secondary impotence (SI), 63 with normal sexual function (NL), and 69 with premature ejaculation (PRE). All were apparently nondiabetic. Diagnoses of diabetes and impaired glucose tolerance were based on serum glucose levels during GTT as recently defined by the National Diabetes Data Group. Covariance analysis corrected for weight and age differences. Mean glucose levels in patients with SI were significantly higher at one and two hours after glucose ingestion than in the other groups. Seven patients with SI (12.1%) were found to have diabetes. The three groups did not differ notably in frequency of impaired glucose tolerance. Inorganic serum phosphate levels were lower for the SI group. The high frequency of diabetes in subjects with SI who have no diabetic symptoms (12.1%) suggests that localized neuropathy or penile ischemia may produce impotence in otherwise asymptomatic patients.