Predictors of Dual Phosphodiesterase Type 5 Inhibitor Therapy in Persons With Erectile Dysfunction and Diabetes

Background While on-demand phosphodiesterase type 5 inhibitors (PDE5i) remain standard therapy for erectile dysfunction (ED), data are lacking for non-responders, particularly those with diabetes, who require dual phosphodiesterase type 5 inhibitor therapy (DPT), i.e, daily low-dose tadalafil and on-demand PDE5i. This represents one of the first studies addressing this critical gap in evidence. Aim To identify the predictors of requirement for dual PDE5i therapy in persons with type 2 diabetes and ED. Methods A retrospective study conducted at a diabetes center in Lucknow, India (November 2020-October 2022), involving a total of 5,243 visits by persons with type 2 diabetes, of which 517 were ED-related visits (n=276). After exclusions, 196 on-demand PDE5i users were included, and 72 non-responders received DPT. Predictors were assessed via multivariate logistic regression. Obesity was defined as body mass index (BMI) ≥25 kg/m² (as per Indian guidelines). Outcomes The primary outcome was the need for DPT, defined by on-demand failure. Results Individuals requiring DPT were older (53 vs. 49 years, p=0.012), had higher creatinine (0.94 vs. 0.9 mg/dL, p=0.033), and had longer diabetes duration (11 vs. 8 years, p=0.005). A significantly higher proportion of individuals with elevated hemoglobin A1c (HbA1c) (p=0.016), increased creatinine levels (p=0.007), and the presence of obesity (p=0.0047) required substantial DPT. Optimal cutoffs were age ≥50, HbA1c ≥8.1%, and creatinine ≥0.82 mg/dL. Conclusion Markers such as age, diabetes duration, HbA1c, obesity, creatinine (ADHOC) predict the need for DPT in type 2 diabetes, enabling personalized ED management. Early recognition of these predictors can help clinicians identify persons likely to require DPT, thus avoiding delays in effective treatment. These findings, though requiring validation in larger and more diverse cohorts, provide an important step toward precision medicine in diabetic men with ED.