Erectile Dysfunction in Diabetes Mellitus: A Comprehensive Narrative Review of Pathophysiology, Genetic Association Studies and Therapeutic Approaches

Introduction

Erectile dysfunction (ED) is a highly prevalent complication of diabetes mellitus (DM), significantly impairing quality of life and psychosocial well-being. The prevalence of ED is estimated to be over 3.5 times higher in men with diabetes mellitus compared to those without. The aetiology of diabetic ED is multifactorial, stemming from complex diabetes mellitus-related systemic changes. The pathophysiology of diabetic ED involves interacting pathways, including endothelial dysfunction, accelerated atherosclerosis, autonomic and peripheral neuropathy, structural penile changes, hormonal imbalances, and psychological factors.

Methods

A review of the literature was conducted to examine the pathophysiological mechanisms, genetic associations, and treatment modalities related to diabetic ED. Particular attention was given to studies exploring pharmacogenetics and emerging therapeutic interventions.

Results

Management is multimodal, including lifestyle changes, counselling, and pharmacological agents (primarily phosphodiesterase type 5 inhibitors (PDE5Is)), but treatment response varies. Genetic studies have identified associations between ED risk/severity and polymorphisms in several candidate genes, including NOS3 (G894T, T786C, VNTR), ARG1/ARG2 (influencing nitric oxide substrate availability), ACE (I/D polymorphism), AR (CAG repeat length affecting androgen sensitivity), and VEGF (promoter polymorphisms). Pharmacogenetic studies suggest that polymorphisms in NOS3, AR, and VEGF may predict response to PDE5Is or testosterone therapy, while ARG1/ARG2 variations might guide future arginase-targeted therapies. Emerging treatments like low-intensity shockwave therapy, platelet-rich plasma, gene therapy, and stem cell therapy show promise but require more robust evidence.

Conclusions

Diabetic ED is a complex condition driven by multiple pathophysiological mechanisms often influenced by an underlying genetic predisposition. Understanding the interplay between pathophysiology and genetics is crucial for developing personalised treatment strategies. While current therapies offer benefits, variability in response highlights the need for tailored approaches. Further research, especially large-scale pharmacogenetic studies and randomised controlled trials for emerging therapies, is essential to identify reliable biomarkers, optimise treatment selection, and improve outcomes for men with diabetic ED.