The Female Sexual Function Index (FSFI) is a psychometrically sound and popular 19-item self-report measure, but its length may preclude its use in studies with multiple outcome measures, especially when sexual function is not a primary endpoint. Only one attempt has been made to create a shorter scale, resulting in the Italian FSFI-6, later translated into Spanish and Korean without further psychometric analysis. Our study evaluated whether a subset of items on the 19-item English-language FSFI would perform as well as the full-length FSFI in peri- and postmenopausal women. We used baseline data from 898 peri- and postmenopausal women recruited from multiple communities, ages 42-62 years, and enrolled in randomized controlled trials for vasomotor symptom management. Goals were to (1) create a psychometrically sound, shorter version of the FSFI for use in peri- and postmenopausal women as a continuous measure and (2) compare it to the Italian FSFI-6. Results indicated that a 9-item scale provided more information than the FSFI-6 across a spectrum of sexual functioning, was able to capture sample variability, and showed sufficient range without floor or ceiling effects. All but one of the items from the Italian 6-item version were included in the 9-item version. Most omitted FSFI items focused on frequency of events or experiences. When assessment of sexual function is a secondary endpoint and subject burden related to questionnaire length is a priority, the 9-item FSFI may provide important information about sexual function in English-speaking peri- and postmenopausal women.
Keywords: Female Sexual Function Index; Menopause; Psychometrics.