Title: Investigating the Relationship Between Pelvic Vein Incompetence and Chronic Pelvic Pain: A Case-Control Study
Funder: Department of Health and Social Care

Abstract: Background Chronic pelvic pain (CPP) in women is a significant health problem, with a prevalence of 24%. Defined as continuous or intermittent infra-umbilical pain of at least six months duration, unrelated to the menstrual cycle, intercourse or pregnancy, CPP has a significant impact on quality of life. It is responsible for 25-30% of all UK gynaecology outpatient appointments and places a substantial financial burden on health services, yet around 55% of women are discharged to primary care or chronic pain services without a diagnosis. Pelvic vein incompetence (PVI) is a potential cause, but its role in pelvic symptoms is unknown. In 2005 a Cochrane review highlighted the urgent need for research to better understand PVI and its impact on women s health. Previous research has been poor quality, often published by clinicians with a financial interest in treating PVI. A recently published Health Technology Assessment identified the clear need for a high quality case-control study. Aim To undertake the first high-quality, adequately powered study on the association between PVI and CPP. This definitive case-control study will recruit 354 premenopausal women aged 18-54 years: 177 with CPP and 177 age and parity matched controls. We will answer the following reserach question: Is the frequency of PVI in premenstrual women with CPP higher than that in age and parity matched women who do not have CPP? Method Cases will be pre-menopausal women aged 18-54 years with a diagnosis of CPP confirmed by their gynaecologist and our diagnostic committee. The patient s gynaecologist must confirm that no further investigation is needed to exclude other causes of pain. Female friends of the cases living in the same area, of similar age and with the similar number of previous pregnancies, with no history of CPP, will be asked to volunteer as controls. The primary outcome measure will be the frequency of PVI on trans-vaginal duplex ultrasound with PVI defined as retrograde venous flow of >0.7sec extending into second order veins. Secondary outcome measures will include the presence of pelvic varices, quality of life measures and healthcare utilisation. Potential patient benefit We completed a pilot study recruiting 51 case-control pairs: PVI was identified in 18 (35.3%) women with CPP compared with 10 (19.6%) controls (p=0.08, OR=2.45, 95%CI=0.95-6.31). Pelvic varices were found in 17 (33.3%) of women with CPP and in 1 (2.0%) control (p This study is also designed to explore the symptoms suffered by women with PVI, with or without pelvic varices. As our pilot study identified that pelvic varices were strongly associated with CPP, it is important to explore whether women with PVI without pelvic varices have sufficient symptoms to justify investigation with a view to treatment. This will be the first adequately designed study to explore the association between PVI, pelvic varices and CPP, providing clinical commissioners, researchers, and the NHS with the essential information they need to plan the investigation and treatment of a condition that affects millions of women.

Lay abstract: Our aim is to study whether women with persistent pelvic pain are more likely to have varicose veins around the womb and ovaries. Over 25% of all UK gynaecology outpatient appointments are for persistent pain in the pelvis (known as chronic pelvic pain or 'CPP') which disrupts womens lives and causes relationship and work difficulties, yet 50% of sufferers never achieve a diagnosis. Varicose veins around the womb and ovaries caused by pelvic vein incompetence may be a cause of this pain. Minimally invasive treatment under local anaesthetic is available but only in the private sector. The NHS requires better quality evidence that pelvic pain is associated with pelvic varicose veins before agreeing to fund investigation and treatment. To participate, women with pelvic pain must have been seen by a gynaecologist to confirm that all necessary tests to exclude other potential causes of their pain have been completed. Each patient (case) asks two female friends around the same age and number of pregnancies to act as healthy 'controls'. The study is then explained to all subjects by the research nurse and all women who agree to take part will: 1. Complete a questionnaire about their symptoms and use of NHS services. 2. Undergo a specialist ultrasound scan inside the vagina to detect varicose veins around the womb and ovaries. If varicose veins around the womb and ovaries are more common in women with CPP than in healthy women, then It is possible that these varicose veins may be causing this chronic and distressing pain. Our results will also identify the symptoms suffered by women with these varicose veins and the NHS costs of caring for them. Because of the large number of women affected by pelvic pain, this novel research has already being presented worldwide and will attract international attention.

Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS
Health categories: RENAL AND UROGENITAL