Association Between Triglyceride-Glucose Index and AVSS-RigiScan Test Parameters in Men With Erectile Dysfunction

Higher TyG index — a proxy for insulin resistance — correlated weakly with lower penile rigidity on objective testing (r = −0.22 at best)

Journal: The Aging Male | Published: 2026-02-11 | Type: Retrospective cohort | PMID: 41671684 Authors: Qian Xin et al. — all from the Department of Urology, Suining Central Hospital, China Funding/COI: Not listed for either

Summary

The triglyceride-glucose (TyG) index — calculated from fasting triglycerides and fasting glucose, used as a surrogate marker for insulin resistance — was negatively correlated with several objective penile rigidity measurements in men with ED. The correlations are statistically significant but weak. The study adds objective penile testing data to a literature that has mostly relied on questionnaire-based ED diagnosis.

Claims

• TyG index negatively correlated with average event rigidity at the penile tip (r = −0.220, p = 0.0001)
• TyG index negatively correlated with average event rigidity at the penile base (r = −0.143, p = 0.013)
• TyG index negatively correlated with average maximum rigidity at the tip (r = −0.165, p = 0.004)
• TyG index negatively correlated with Δ tumescence at the tip (r = −0.124, p = 0.031)
• All four associations are in the same direction: higher metabolic burden, lower rigidity

Study Quality

This is a single-center retrospective study from one hospital in China. The 276 ED patients were evaluated using AVSS-RigiScan — audio-visual sexual stimulation combined with a device that continuously measures tumescence and rigidity at the penile tip and base, which is a more objective outcome than questionnaire scores like the IIEF. That methodological choice is the study's main selling point.

The control group, however, is 28 men drawn from health checkups and premarital exams — a wildly different clinical context than the ED cohort and far too small for meaningful comparison. The abstract does not report whether confounders (age, BMI, diabetes status, hypertension, smoking) were adjusted for in the correlation analysis, which is a significant omission given that TyG index is tightly linked to all of those variables.

Red Flags

• Tiny, non-comparable control group (28 men from premarital exams vs. 276 clinical ED patients)
• All four r-values fall between −0.12 and −0.22 — statistically significant given n = 276, but explaining at most ~5% of variance
• No funding or conflict-of-interest disclosure
• Single center; all authors from the same department
• Abstract does not describe multivariate adjustment for age, BMI, diabetes, or hypertension — all major ED confounders that also correlate with TyG index
• Retrospective design cannot establish causation
• No description of how ED diagnosis was made or patient selection criteria

Strengths

• Uses objective penile rigidity measurement (RigiScan) rather than questionnaire alone
• Distinguishes tip vs. base rigidity, which can indicate whether vascular dysfunction is proximal or distal
• Reasonably sized case cohort (n = 276)
• Reports exact correlation coefficients and p-values rather than hand-waving

Verdict

The use of AVSS-RigiScan distinguishes this from the many ED-metabolic marker papers that rely solely on self-report. But the correlations are weak, the control group is too small and poorly matched to be meaningful, and the absence of any multivariate model makes it impossible to know whether TyG index is doing independent work or just proxying for age and BMI. This is a preliminary signal paper — useful as a reference for effect sizes if someone designs a properly controlled study, not useful on its own.