What is the best biological parameter to predict erectile dysfunction in men aged >55 years with type 2 diabetes?

To date, there is no evidence regarding the best biological marker to predict erectile dysfunction (ED) in men aged >55 years with type 2 diabetes. This prospective study included data from men aged >55 years with type 2 diabetes. ED was assessed by the International Index of Erectile Function 15‐item survey. Total testosterone (TT) levels and bioavailable testosterone were measured; the free testosterone index was calculated. Data from 155 men (aged 64 ± 7 years) were explored. The prevalence of ED and testosterone deficiency was 78.7% and 34.8%, respectively. After univariate analysis, TT and bioavailable testosterone were associated with ED (P = 0.01). After multivariate analysis, and adjustment for age, body mass index, tobacco, alcohol, duration of diabetes, TT, bioavailable testosterone, vitamin D and high‐sensitivity C‐reactive protein, we found that only high‐sensitivity C‐reactive protein was significantly predictive of ED. TT could predict ED, but it lacks specificity. We found a potential role of high‐sensitivity C‐reactive protein as a predictive marker of ED in this targeted population.