This retrospective single-center case-control study evaluates whether the Modified EASIX score (LDH × CRP / Platelets), calculated from routine blood tests, predicts severity of erectile dysfunction (ED) as measured by the IIEF-5 questionnaire. Medical records from January 1, 2024 to September 30, 2025 will be reviewed. Patients will be classified by IIEF-5 (≤21 = ED; ≥22 = no ED) and Modified EASIX distributions and predictive performance (ROC/AUC) will be compared between groups. No additional interventions will be performed.

This retrospective observational study will include adult male patients aged 18-65 attending the urology outpatient clinic. Demographic data, comorbidities, IIEF-5 scores and routine laboratory results (LDH, CRP, platelet count and other routine biochemistry/hematology) obtained during routine follow-up will be extracted from medical records covering January 2024-September 2025. The Modified EASIX score will be computed as: LDH × CRP / Platelets. Patients will be grouped according to IIEF-5: ED group (IIEF-5 ≤21) and non-ED group (IIEF-5 ≥22). Primary analyses include group comparisons of Modified EASIX, correlation analyses with IIEF-5, logistic regression for association and ROC analysis to evaluate discriminatory performance and optimal cut-offs. Analyses will use IBM SPSS 27 and GraphPad Prism 9. No changes to patient management were made for study purposes; no additional sampling or interventions were performed.

Inclusion Criteria:

Male patients aged 18-65. Followed at the urology outpatient clinic with a documented IIEF-5 questionnaire.

Available routine laboratory data including LDH, CRP and platelet count within the study period (Jan 1, 2024 - Sep 30, 2025).

Exclusion Criteria:

Use of penile prosthesis. Patients without an organic ED diagnosis when relevant (per protocol: "Patients without an organic ED diagnosis will be excluded from the study").

Missing essential data for Modified EASIX calculation or IIEF-5.

Only self-identified male participants aged 18-65 are eligible, as the study focuses on erectile dysfunction, a condition specific to individuals with male genital anatomy.

Adult male patients aged 18-65 who attended the urology outpatient clinic and had documented IIEF-5 scores and routine laboratory results (LDH, CRP, platelet count) between January 2024 and September 2025. The study includes both patients with erectile dysfunction (IIEF-5 ≤ 21) and those without erectile dysfunction (IIEF-5 ≥ 22), using retrospectively collected medical records from a single center (Defne State Hospital).

Individual participant data (IPD) will not be publicly shared because the study is based on retrospective medical records containing sensitive personal health information. Due to privacy concerns and institutional data-protection regulations, de-identified datasets cannot be released outside the research team.