This review concluded that there was some evidence to suggest that pharmaceutical interventions to treat female sexual dysfunction improve one or more aspects of sexual function, but it is unclear whether these improvements are clinically meaningful. Given the limited number and quality of the studies, the authors' cautious conclusions are likely to be reliable and their suggestions for further research warranted.

To review randomised controlled trials (RCTs) of pharmaceutical interventions to treat female sexual dysfunction (FSD) in order to optimise the design of future studies.

PubMed was searched from 1980 to 2005; the search terms were reported. Additional studies were identified from the reference lists of retrieved articles.

Study designs of evaluations included in the review

Randomised controlled trials (RCTs) were eligible for inclusion in the review.

Specific interventions included in the review

Studies of pharmaceutical treatments for FSD were eligible for inclusion. The included studies evaluated sildenafil or testosterone/methyltestosterone, with a wide range of doses and regimens used across studies.

Participants included in the review

Studies of healthy women with FSD were eligible for inclusion. FSD was defined according to the American Psychiatric Association's revised Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) or the American Foundation for Urologic Diseases (AFUD) classifications. Hypoactive sexual desire disorder, female sexual arousal disorder, female orgasmic disorder and sexual pain disorders were included. Surgically menopausal women were excluded from the review. The age of women in the included studies ranged from 18 to 78 years.

Outcomes assessed in the review

Eligible studies had to include specific and comprehensive measures of sexual function, either questionnaire or hormone measurements. Behavioural, physiological and psychological outcomes, measured using clinical or laboratory tests, outcome scales and personal diaries, were reported.

How were decisions on the relevance of primary studies made?

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

The review was restricted to double-blind RCTs. Study quality was further assessed in relation to statistical power, participant inclusion and exclusion criteria, participant definition, outcomes, outcome measurement methods and treatment duration. The authors did not state how many reviewers performed the assessment.

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction. Changes in sexual behaviour and response were extracted.

How were the studies combined?

The studies were combined in a narrative, grouped according to the methodological criteria being investigated.

How were differences between studies investigated?

Differences between the studies were discussed in the text, and study details and results were tabulated.

Eleven RCTs (n=3,056) were included in the review. Three were crossover studies.

Quality.

Five studies were sufficiently powered to detect a statistically significant difference between the intervention and placebo groups. Many studies used subjective outcomes that were open to bias, and there was no consensus on the types of participants included in the studies.

Effectiveness.

Two studies evaluating sildenafil and all seven evaluating testosterone/methyltestosterone showed some improvement in one or more aspect of sexual function with treatment; the other studies showed differences between the intervention and placebo groups.

Of the two sildenafil studies with adequate statistical power, one reported no change in sexual response and the other an increase in genital sensation and satisfaction.

The three testosterone/methyltestosterone trials with adequate statistical power reported increases in satisfying sexual activity and sexual desire, accompanied by a decrease in personal distress, with treatment.

The majority of included studies showed some improvement in one or more aspects of sexual function. However, it is unclear whether these improvements are clinically meaningful.

This review was based on a clear review question. The reviewers only searched PubMed and the reference lists of retrieved publications, and made no attempt to locate unpublished material, therefore publication bias might have affected the findings. It was unclear whether language restrictions were applied during the search, thus there is the potential for language bias. It was unclear to what extent bias and errors might have arisen through the study selection, quality assessment and data extraction processes, as these review methods were not described. The quality of the studies was, however, assessed, this being one of the main aims of the review.

Given the differences between the included studies in terms of their participants and outcomes, the use of a narrative synthesis was appropriate. The authors' findings also took the validity of the studies into account, in particular their statistical power. However, given that effectiveness was not the main focus of this review and the evidence is limited by the number, size and quality of the studies, the authors' cautious conclusions are likely to be reliable and their suggestions for further research warranted.

The lead reviewer is employed by Organon. However, Organon did not fund the study, which was part of the reviewer's thesis.

Practice: The authors did not state any implications for practice.

Research: The authors recommended that future studies should assess statistically significant improvements that are clinically meaningful. Consensus should also be reached in relation to: what is the minimal important difference in effect size; inclusion and exclusion criteria for defining the FSD population; primary outcome measures; and trial end points which reflect clinically relevant outcomes embedded in a biopsychosocial sexual response model for women.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.