Investigation of the Effect of the Atherogenic Index on the Therapeutic Response to Tadalafil in Patients With Vascular Erectile Dysfunction

The atherogenic index of plasma (AIP) is a laboratory-based marker of atherogenic dyslipidemia and subclinical atherosclerosis. AIP was calculated as log10(triglycerides/high-density lipoprotein cholesterol) after conversion of both lipid values to mmol/L. Because vascular and metabolic abnormalities contribute to erectile dysfunction and may influence response to phosphodiesterase type 5 inhibitors, baseline AIP may be associated with treatment outcomes during tadalafil therapy.

This was a prospective, single-center observational cohort study of men aged 40 years or older with predominantly vasculogenic erectile dysfunction based on clinical assessment and predefined eligibility criteria. Participants were consecutively enrolled from an outpatient urology clinic. Baseline demographic, clinical, and laboratory data were recorded. Tadalafil 5 mg once daily was prescribed as part of routine clinical care, independently of study participation, and enrolled participants were prospectively followed for 12 weeks.

Erectile function was assessed using the six-item International Index of Erectile Function-Erectile Function domain (IIEF-EF) at baseline and Week 12. The primary objective was to evaluate the association between baseline AIP and tadalafil treatment response. Treatment response was defined as an increase of at least 4 points in the IIEF-EF score from baseline to Week 12; an increase of less than 4 points was classified as nonresponse.

Because all participants received tadalafil and the study did not include an untreated or placebo comparator, the association between AIP and outcome was interpreted as prognostic during tadalafil treatment rather than as evidence of causality or differential treatment benefit.