ED secondary to diabetes mellitus
ED is a common problem afflicting over a third of all men with diabetes mellitus type 2, and diabetes is independently responsible for a 3- to 4-fold increase in the risk of ED according to a survey of 1460 diabetic men. ED is strongly related to the severity of diabetes, with a higher incidence in patients with a long history of diabetes, patients using insulin, and patients with microvascular complications of diabetes. Diabetic men with ED also have significantly worse disease-specific health-related quality of life.
In the largest original, prospective trial of tadalafil (Cialis) in diabetic men, Sáenz de Tejada and co-workers reported that tadalafil significantly improves ED and is well tolerated in this population. A total of 216 men with type 1 or type 2 diabetes mellitus were randomized to placebo, tadalafil 10 mg, or tadalafil 20 mg to be taken on-demand up to once daily for 12 weeks. The IIEF-EF, the SEP, and a GAQ were used to evaluate efficacy. The average age was 56, and the duration of diabetes was 12 years on average. Ninety-one percent of men had type 2 diabetes while 9% had type 1 diabetes, 22% had microvascular complications, and over 81% of men had poorly controlled diabetes with a hemoglobin A1c of greater than 7.0%. The baseline IIEF-EF was 12, corresponding to moderate severity ED.
In diabetic men taking tadalafil 10 mg or 20 mg, the IIEF-EF was improved by 6.4 and 7.3, respectively, compared with 0.1 with placebo (p < 0.001). Successful intercourse was improved by 28% and 29% in the two tadalafil groups versus only 1.9% in the placebo group (p < 0.001). The GAQ revealed that only 25% of men in the placebo group felt they had improved erections, compared with 56% and 64% of men in the tadalafil 10 mg and tadalafil 20 mg groups, respectively (p < 0.001).
Results from a large, retrospective analysis of 12 randomized controlled trials of tadalafil including over 600 diabetic men parallels the data reported by Sáenz de Tejada. The trials included in this retrospective analysis were many of the same trials analyzed in other integrated analyses reported here in this review. The average age was 57, and diabetic men had more severe ED than patients without diabetes at baseline with a mean IIEF-EF of 12.6 compared to 15 in patients without diabetes (p < 0.001). Comorbid conditions more common in the patients with diabetes included hypertension, hyperlipidemia, and coronary artery disease.
Diabetic men in the tadalafil 10 mg and tadalafil 20 mg groups had improvements of 6.2 and 7.4 in their IIEF-EF, respectively, versus 0.9 for placebo (p < 0.001). Successful intercourse was improved by 30% and 37% in the tadalafil 10 mg and 20 mg groups, respectively, compared with 4% in the placebo group (p < 0.001). Overall, erections were reported as improved in 75% for the 20 mg group, 61% for the 10 mg group, and 30% for the placebo group. According to these studies, ED secondary to diabetes is certainly amenable to treatment with tadalafil.