UCLA

Background

Limited information is available on the performance characteristics of 2 questionnaires commonly used in clinical research, the Psychosexual Daily Questionnaire (PDQ) and the Derogatis Interview for Sexual Function (DISF)-II Assessment, especially in older men with low testosterone (T) and impaired sexual function.

Aim

To determine reliability of PDQ and DISF-II by assessing the correlation within and between domains in the questionnaires and to define clinically meaningful changes in sexual activity (PDQ question 4 [Q4]) and desire (DISF-II sexual desire domain [SDD]) domains.

Methods

Data from 470 men participating in the T Trials were used to calculate Spearman correlation coefficients of individual items and total score among questionnaires to determine convergent and construct validity. Clinically meaningful changes for sexual desire and activity were determined by randomly dividing the sample into training and validation sets. Anchor- and distribution-based clinically meaningful change criteria were defined in the training set, and selected changes were evaluated in the validation set.

Outcomes

Validity of the PDQ and DISF-II and clinically meaningful changes in sexual desire and activity were determined in older men in T Trials.

Results

Moderate to strong correlations were shown within and between domains from different questionnaires. Using Patient Global Impression of Change as an anchor, clinically meaningful change in PDQ sexual activity was ≥0.6, and in DISF-SDD was ≥5.0. Applying these change cut-points to the validation set, a greater proportion of T-treated men achieved clinically meaningful improvement in their sexual desire and activity compared to placebo-treated men.

Clinical implications

The PDQ-Q4 and DISF-II-SDD can be used to reliably assess clinically meaningful changes in sexual activity and sexual desire in hypogonadal men treated with T.

Strengths & limitations

Strengths of this study include a large sample size, long trial duration, and inclusion of men with low libido and unequivocally low T levels. Limitations include using data from a single study that enrolled only older hypogonadal men, and only 1 anchor for both sexual desire and activity.

Conclusion

Moderate to strong correlations were demonstrated within and between different sexual domains of the PDQ and DISF-II confirming construct and convergent validity. Clinically meaningful improvement in elderly hypogonadal men was change of ≥0.6 score in the PDQ-Q4 and ≥5.0 in the DISF-SDD. Improvements in sexual activity and desire in the T Trials were modest but clinically meaningful. Wang C, Stephens-Shields AJ, DeRogatis LR, et al. Validity and Clinically Meaningful Changes in the Psychosexual Daily Questionnaire and Derogatis Interview for Sexual Function Assessment: Results From the Testosterone Trials. J Sex Med 2018;15:997-1009.