Comparison of Validated Instruments Measuring Sexual Function in Men

Objectives: There is no universally accepted instrument to measure sexual function (SF) in men. We compare validated SF measures in a single cohort. Methods: We compare the Sexual Health Inventory for Men (SHIM), Expanded Prostate Cancer Index Composite SF domain (EPIC-SF), and a reconstructed University of California Los Angeles Prostate Cancer Index SF domain (PCI-SF) in 856 men scheduled for radical prostatectomy. We define potency thresholds for the PCI-SF and EPIC-SF. Results: Mean age, body mass index, Gleason sum, and PSA were 57 years, 26.7 kg/m2, 6.3, and 5.9 ng/mL, respectively. Mean instrument scores were as follows: SHIM 20.1; EPIC-SF 65; PCI-SF 71. All instruments were significantly intercorrelated (r = 0.99 for EPIC-SF vs PCI-SF, r = 0.75 for SHIM vs EPIC-SF, r = 0.77 for SHIM vs PCI-SF, all P < .001). The SHIM had the greatest negative skew and ceiling effect (P < .001). Although high scores on either the EPIC-SF or PCI-SF translated reliably to high SHIM scores, the reverse was not true. Subjects who reported no erectile dysfunction (ED) on the SHIM (>22) had diverse overall SF, whereas those who scored highly on the EPIC-SF or PCI-SF had both excellent erectile function (potency) and overall SF (including orgasmic function, erectile function, and sexual desire). EPIC-SF scores >65 and PCI-SF scores >75 define men that are both potent and have good SF. ConclusionsL The SHIM is intended as an instrument to assess ED. It is, however, inadequate as a measure of overall SF. The EPIC-SF and PCI-SF capture gradations of both sexual and erectile function and may also be used to define potency more comprehensively.