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Methods to Determine the Minimum Important Difference for a Sexual Event Diary Used by Postmenopausal Women with Hypoactive Sexual Desire Disorder


Tara Symonds, PhD, Worldwide Outcomes Research, Pfizer Ltd. (IPC160), Sandwich, Kent, CT13 9NJ, UK. Tel: +44-1304-641553. Fax: +44-1304-658823; E-mail:


Introduction.  Recently, there has been much discussion in the literature about how to determine the meaningfulness of results generated from a patient-reported outcome measure. A number of reviews have shown that there are two main approaches: anchor- and distribution-based approaches for determining the minimum important difference (MID) for a new measure. There are issues with calculating an MID using each method: Will the two approaches give the same estimate? If the estimates differ, how do you decide on one estimate? Would asking patients directly be more beneficial?

Aim.  A case study was presented to address these issues based on a newly developed diary assessing number of satisfactory sexual events (SSEs) per week in women with hypoactive sexual desire disorder (HSDD).

Methods.  Anchor- and distribution-based estimates were generated from data gathered in two double-blind, placebo-controlled, parallel group trials for the treatment of HSDD (N = 788). A novel interview study was used to ask women directly about an MID for SSEs (N = 77).

Main Outcome Measures.  Defining the MID for an SSE diary in women with HSDD.

Results.  The estimates varied, producing a range of mean MID estimates between 0.04 and 0.46 SSEs per week.

Conclusion.  We recommend that rather than defining the MID, a range should be selected from the set of estimates formed by the limits of the 95% confidence intervals. Symonds T, Spino C, Sisson M, Soni P, Martin M, Gunter L, and Patrick DL. Methods to determine the minimum important difference for a sexual event diary used by postmenopausal women with hypoactive sexual desire disorder. J Sex Med 2007;4;1328–1335.