Vulvodynia is not created equally: empirical classification of women with vulvodynia

Abstract

Meryl Alappattu,1,2 Georgine Lamvu,3,4 Jessica Feranec,3,4 Kathryn Witzeman,5 Michael Robinson,2,6 Andrea Rapkin7 1Department of Physical Therapy, 2Center for Pain Research and Behavioral Health, University of Florida, Gainesville, 3Division of Surgery, Gynecology Section, Veteran Affairs Medical Center, 4University of Central Florida, Orlando, FL, 5Women’s Integrated Health Program, Department of OBGYN, Denver Health Medical Center, Denver, CO, 6Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, 7Department of Obstetrics and Gynecology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA Background: Vulvodynia classification is based on the sensory dimensions of pain and does not include psychological factors associated with the pain experience and treatment outcomes. Previous work has shown that individuals with chronic pain can be classified into subgroups based on pain sensitivity, psychological distress, mood, and symptom severity.Objective: The aim of this study was to identify distinct subgroups of women with vulvodynia enrolled in the National Vulvodynia Registry. We hypothesized that women with vulvodynia can be clustered into subgroups based on distress and pain sensitivity.Design: A cross-sectional study.Methods: We conducted an exploratory hierarchical agglomerative cluster analysis using Ward’s cluster method and squared Euclidean distances to identify unique subgroups based on baseline psychological distress and pain sensitivity. The variables included the catastrophizing subscale of the Coping Strategies Questionnaire, the Beck Depression Inventory, the State Trait Anxiety Index-Trait scale, McGill Pain Questionnaire-Affective subscale, and vulvar and pelvic muscle pressure pain sensitivity.Subjects: Eight sites enrolled women who presented with vaginal or vulval pain of at least 3-month duration.Results: Two distinct subgroups, high pain sensitivity with high distress (n=27) and low pain sensitivity with low distress (n=100), emerged from the cluster analysis. Validation indicated that subgroups differed in terms of clinical pain intensity, sensory aspects of pain, and intercourse pain.Conclusion: Empirical classification indicates that unique subgroups exist in women with vulvodynia. Providers should be aware of the heterogeneity of this condition with respect to pain-related distress and pain sensitivity. Keywords: vulvodynia, chronic vulvar pain, pelvic pain, National Vulvodynia Registry, classification, patient subgroups

Keywords

• Vulvodynia
• chronic vulvar pain
• pelvic pain
• national vulvodynia registry