Psychometric testing of two new patient‐reported outcome instruments for the evaluation of treatment for hypogonadism

AIM The aim of this study was to perform psychometric testing and estimate minimal important change (MIC) of two new patient-reported outcome (PRO) instruments - Sexual Arousal, Interest and Drive Scale (SAID) and Hypogonadism Energy Diary (HED). METHODS New PRO instruments were administered immediately after screening (Time 1, test-retest subset only) and immediately prior to both randomisation (Time 2) and end-point (Time 3) to men participating in a randomised clinical trial comparing the effect of testosterone solution 2% (TS) and placebo on serum total testosterone. Psychometric analyses included reliability, validity and responsiveness. Total scores for both PRO instruments were transformed to a 0-100 scale. RESULTS Study participants (n = 694) were 80% age ≤ 65 years, 79% White, with mean baseline testosterone = 202 ng/dl. Clinicians identified 86% subjects as having low sex drive, 86% with low energy and 76% with both symptoms. Reliability analyses for SAID and HED yielded reliability coefficients > 0.70. SAID scores discriminated between men having low sex drive (n = 553) and those who did not (n = 80) (34.5 vs. 42.8, p < 0.001). HED scores discriminated between men having low energy (n = 541) and those who did not (n = 64) (48.9 vs. 60.2, p < 0.001). In the men randomised to TS (vs. placebo), SAID and HED detected effect sizes of 0.61 (vs. 0.39) and 0.68 (vs. 0.48), respectively. MIC estimates for SAID and HED were approximately 10 and 8, respectively. CONCLUSIONS This study provided evidence of the reliability, validity and responsiveness of SAID and HED as measures of sex drive and energy, respectively, making them potentially useful for evaluation of hypogonadal treatment.