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Also known as
IIEF-15, International Index of Erectile Function Questionnaire, IIEF Questionnaire, IIEF-EF (Erectile Function domain only), IIEF-6 (six-item version), SHIM (Sexual Health Inventory for Men, also known as IIEF-5)
Definition
The International Index of Erectile Function (IIEF) is a widely used, multi-dimensional self-report instrument designed for the standardized assessment of male sexual function.1 Developed in 1997 by Rosen and colleagues, it serves as a brief, reliable, self-administered measure of erectile function that is cross-culturally valid and psychometrically sound.2 The IIEF consists of 15 items that evaluate five distinct domains of male sexual function: erectile function (six items), orgasmic function (two items), sexual desire (two items), intercourse satisfaction (three items), and overall satisfaction (two items).3
The questionnaire employs a recall period of four weeks and uses a five-point Likert-type scale for responses, with higher scores indicating better sexual function.4 The erectile function domain (questions 1-5, 15), often used as a standalone instrument known as the IIEF-6 or IIEF-EF, has become the gold standard for the clinical assessment of erectile dysfunction (ED) severity.5 This domain categorizes ED into five severity levels: severe (1-10), moderate (11-16), mild to moderate (17-21), mild (22-25), and no ED (26-30).6
The IIEF demonstrates excellent psychometric properties, including high internal consistency (Cronbach’s alpha values of 0.73 and higher across domains), test-retest reliability, and construct validity.7 It has been linguistically validated in over 32 languages and used as a primary endpoint in more than 50 clinical trials, making it the most widely accepted instrument for assessing treatment efficacy in erectile dysfunction research.8
Clinical Context
The IIEF is extensively used in clinical settings for multiple purposes related to the assessment and management of erectile dysfunction.1 Primarily, it serves as a diagnostic tool for identifying the presence and severity of erectile dysfunction, allowing clinicians to objectively categorize patients into different severity groups based on standardized scoring criteria.2 This standardization facilitates consistent communication among healthcare providers and helps determine appropriate treatment approaches based on ED severity.
In the initial evaluation of patients presenting with sexual dysfunction complaints, the IIEF provides a comprehensive assessment that covers multiple domains of sexual function beyond just erectile capacity, including orgasm, desire, intercourse satisfaction, and overall sexual satisfaction.3 This multidimensional approach helps clinicians identify specific areas of sexual dysfunction that may require targeted interventions.
The IIEF has become the gold standard outcome measure in clinical trials evaluating treatments for erectile dysfunction, including pharmacological interventions (such as phosphodiesterase type 5 inhibitors), surgical procedures, and device therapies.4 Its sensitivity to treatment-related changes makes it invaluable for monitoring therapeutic efficacy and comparing different treatment modalities. For instance, the questionnaire demonstrated significant sensitivity in detecting improvements in erectile function following treatment with sildenafil, tadalafil, and vardenafil in numerous clinical trials.5
In specialized urology and sexual medicine practices, the IIEF is routinely administered before and after interventions to objectively document treatment outcomes.6 This practice is particularly important in the context of prostate cancer treatment, where erectile dysfunction is a common side effect of radical prostatectomy, radiation therapy, and androgen deprivation therapy.7 The questionnaire helps quantify the impact of these treatments on sexual function and guides subsequent management strategies.
Additionally, the IIEF has applications in epidemiological research, allowing for standardized assessment of erectile dysfunction prevalence across different populations and identification of risk factors associated with sexual dysfunction.8 This research has significant implications for public health initiatives aimed at addressing erectile dysfunction and associated comorbidities such as cardiovascular disease, diabetes, and depression.