Background: Chronic pain problems involving the female reproductive system are major health concerns in women of all ages. As conditions which are poorly understood and often misdiagnosed or ignored, they entail a great personal cost to patients and a significant financial cost to society. One such condition is vulvodynia, or chronic unexplained vulvar pain. A recent population-based study suggests that the lifetime cumulative incidence of vulvodynia is 16%, indicating that approximately 2.5 million Canadian women may experience idiopathic vulvar pain during their lifetimes. Provoked vestibulodynia (PVD) - an acute recurrent pain localized within the vulvar vestibule and experienced primarily during sexual intercourse - is suspected to be the most frequent cause of vulvodynia in premenopausal women, with prevalence estimates of 12% in community samples. Despite its high prevalence and negative impact on psychosexual functioning, there has been a paucity of controlled research to provide empirically validated treatments for afflicted couples. The present proposal draws on our previous cross-sectional and prospective CIHR funded research on the dyadic determinants of pain and psychosexual impairment in women with PVD and their partners, as well as on our past randomized trials evaluating the efficacy of group cognitive-behavioral therapy for this condition. Specifically, the goal of our study is to evaluate the efficacy of a targeted cognitive-behavioral couple therapy (CBCT) intervention that we developed for the treatment of PVD.

Objectives: The proposed two-centre randomized clinical trial aims to evaluate the efficacy of a novel 12-week targeted couple therapy intervention (CBCT) for women with PVD in comparison to one of the most frequently prescribed first line medical interventions, topical lidocaine, shown to be effective and safe in the management of PVD. The primary research question focuses on whether there is a significant difference between the two treatments on women's pain during intercourse post-treatment. Secondary research questions focus on whether there are significant differences between the two treatments post-treatment and at 6-month follow-up on (a) the multidimensional aspects of women's pain on the McGill Pain Questionnaire and (b) women and partners' sexuality (sexual function and satisfaction, frequency of intercourse), psychological adjustment (anxiety, depression, catastrophizing, self-efficacy, pain attributions, quality of life, acceptance of pain, compassionate love for partner, self-compassion, emotion regulation and thoughts and feelings related to pain experience), relationship factors (partner responses, dyadic adjustment, attachment, and communication) and self-reported improvement and treatment satisfaction. We will also examine whether childhood trauma and co-morbid pain conditions moderate treatment response. Finally, a third research question is to evaluate the role of hormonal contraceptive use and the risk of PVD.

Research plan/methodology: The proposed research is a 3.5-year, two-centre parallel randomized controlled trial for PVD using an intent-to-treat analysis strategy, with pain during intercourse as the primary outcome. The main research questions will be addressed by: 1) recruiting 224 premenopausal women and their partners with medically diagnosed PVD; 2) performing comprehensive gynecological and psychosexual pre-treatment evaluations focusing on our outcome measures; 3) randomly assigning women to one of the two 12-week treatment arms: CBCT or lidocaine, and 4) evaluating pain during intercourse, as well as sexual, psychological and relationship outcomes, in addition to self-reported improvement and treatment satisfaction, post-treatment and at 6-month follow-up. These procedures will take place in two different university centers: Université de Montréal in Montréal, Québec, and Dalhousie University in Halifax, Nova Scotia, and their affiliated hospitals. Both university centres will store data securely, adhering to the protocols outlined by the ethics review boards at each site.

Statistical Analyses: Analyses will be conducted based on intention to treat. Descriptive statistics will be used to define and compare the participants in both intervention groups. More specifically, we will calculate means, medians, deviations and interquartile ranges and T-tests will be used to determine the differences between groups for socio-demographic variables. Chi-square tests and observed differences between groups will be used for categorical variables. If differences are observed between groups, these variables will be controlled for in subsequent analyses. We will verify that variables are normally distributed. If variables are not normally distributed, non-parametric tests will be employed. A repeated measures analysis of variance will permit the assessment of efficacy of the two treatments at post-treatment and at 6-month follow-up. The analyses will focus on the changes in pain experienced during intercourse from pre-treatment assessment to post-treatment and 6-months follow-up. To do this, time will be the intra-subject variable, and the experimental condition will be the inter-subject variable.

For secondary analysis, multiple analyses will be conducted in multiple steps, with multivariate analyses being conducted first for repeated measures (MANOVA). Correlated measures will be grouped based on conceptual domain (e.g., pain, dyadic adjustment, catastrophizing). Univariate analyses will be conducted if the multivariate results are significant (ANOVA). This will be followed by orthogonal contrasts to examine changes between different measurements. Moreover, we will use exploratory analyses for participants who completed the experimental protocol to determine the effect protocol adherence has on treatment efficacy. Multiple regression analyses will be used to examine the link between socio-demographic variables, pre-treatment dependent variables and pain at post-treatment and 6-months follow-up to identify factors associated with therapeutic success. These latter analyses will be conducted for each treatment group separately. Bonferroni corrections will be used during analyses for multiple comparison adjustments. In the case of missing data, we will explore the effects of withdrawal on sensitivity analyses, replace the missing data with data from the most recent assessment or with averaged or aggregate values.

Significance of study: Results of the proposed research may improve the health and quality of life of Canadians afflicted with a highly prevalent and neglected women's health problem - vulvodynia - by providing a rigorous test of the efficacy of a novel targeted couple therapy intervention.