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Updated: Jul 8, 2026

Treatment Model for Young Patients with Psychogenic Erectile Dysfunction and Resultant Infertility
Published on: May 30, 2025
Geometric mean IELT and premature ejaculation: appropriate statistics to avoid overestimation of treatment efficacy
Marcel D Waldinger1, Aeilko H Zwinderman, Berend Olivier
1Department of Psychiatry and Neurosexology, Haga Hospital Leyenburg, The Hague, The Netherlands. md@waldinger.demon.nl
Introduction:
The intravaginal ejaculation latency time (IELT) behaves in a skewed manner and needs the appropriate statistics for correct interpretation of treatment results.
Aims:
To explain the rightful use of geometrical mean IELT values and the fold increase of the geometric mean IELT because of the positively skewed IELT distribution.
Methods:
Linking theoretical arguments to the outcome of several selective serotonin reuptake inhibitor and modern antidepressant study results.
Main Outcome Measures:
Geometric mean IELT and fold increase of geometrical mean IELT.
Results:
Log-transforming each separate IELT measurement of each individual man is the basis for the calculation of the geometric mean IELT. A drug-induced positively skewed IELT distribution necessitates the calculation of the geometric mean IELTs at baseline and during drug treatment. In a positively skewed IELT distribution, the use of the "arithmetic" mean IELT risks an overestimation of the drug-induced ejaculation delay as the mean IELT is always higher than the geometric mean IELT. Strong ejaculation-delaying drugs give rise to a strong positively skewed IELT distribution, whereas weak ejaculation-delaying drugs give rise to (much) less skewed IELT distributions. Ejaculation delay is expressed in fold increase of the geometric mean IELT.
Conclusions:
Drug-induced ejaculatory performance discloses a positively skewed IELT distribution, requiring the use of the geometric mean IELT and the fold increase of the geometric mean IELT.
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