Correction: A two-arm parallel double-blind randomised controlled pilot trial of the efficacy of Omega-3 polyunsaturated fatty acids for the treatment of women with endometriosis-associated pain (PurFECT1).

[This corrects the article DOI: 10.1371/journal.pone.0227695.].

A two-arm parallel double-blind randomised controlled pilot trial of the efficacy of Omega-3 polyunsaturated fatty acids for the treatment of women with endometriosis-associated pain (PurFECT1).

BACKGROUND: Endometriosis is defined by the presence of endometrial-like tissue (lesions) outside the uterus, commonly on the pelvic peritoneum. It affects 6-10% of women and is associated with debilitating pelvic pain. Current management options are often unsatisfactory. Omega-3 polyunsaturated fatty acids (O-PUFA) have the potential to reduce the painful symptoms associated with endometriosis, reduce lesion size, preserve the patient's ability to conceive, and have minimal side effects. We performed a two-arm, parallel double-blinded randomised controlled trial to inform the planning of a future multicentre randomised controlled trial to evaluate the efficacy of O-PUFA for endometriosis-associated pain. OBJECTIVES: The primary objectives of the trial were to assess recruitment and retention rates. The secondary objectives were to determine the acceptability to women of the proposed methods of recruitment, randomisation, treatments and questionnaires, to estimate the variability in the proposed primary endpoints to inform the sample size calculation and to refine the research methodology for the future definitive trial. METHODS: We recruited women with endometriosis from June 2016 to June 2017 and randomised them to eight weeks of treatment with O-PUFA or olive oil. Pain scores and quality of life questionnaires were collected at baseline and eight weeks. We calculated the proportion of eligible women randomised, and of randomised participants who were followed up to eight weeks. Acceptability questionnaires were used to evaluate women's experiences of the trial. RESULTS: The proportion of eligible participants who were randomised was 45.2% (33/73) and 81.8% (27/33) completed the study. The majority of participants described their overall trial experience favourably and there were no adverse events in either group. CONCLUSION: Our pilot trial supports the feasibility of a future larger trial to definitively evaluate the efficacy of O-PUFA for endometriosis-associated pain. TRIAL REGISTRATION: The trial was registered on the ISRCTN registry (registration number ISRCTN44202346).

A pilot randomised double blind controlled trial of the efficacy of purified fatty acids for the treatment of women with endometriosis-associated pain (PurFECT): study protocol.

BACKGROUND: Endometriosis affects 6-10% of women and is associated with debilitating pelvic pain. It costs the UK > £2.8 billion per year in loss of productivity. Endometriosis can be managed by surgical excision or medically by ovarian suppression. However, ~ 75% symptoms recur after surgery and available medical treatments have undesirable side effects and are contraceptive. Omega-3 purified fatty acids (PUFA) have been shown in animal models to reduce factors that are thought to lead to endometriosis-associated pain, have minimal side effects, and no effects on fertility. This paper presents a protocol for a two-arm, pilot parallel randomised controlled trial (RCT) which aims to inform the planning of a future multicentre trial to evaluate the efficacy of Omega-3 PUFA in the management of endometriosis-associated pain in women. METHODS: The study will recruit women with endometriosis over a 12-month period in the National Health Service (NHS) Lothian, UK, and randomise them to 8 weeks of treatment with Omega-3 PUFA or comparator (olive oil). The primary objective is to assess recruitment and retention rates. The secondary objectives are to determine the effectiveness/acceptability to participants of the proposed methods of recruitment/randomisation/treatments/questionnaires, to inform the sample size calculation and to refine the research methodology for a future large randomised controlled trial. Response to treatment will be monitored by pain scores and questionnaires assessing physical and emotional function compared at baseline and 8 weeks. DISCUSSION: We recognise that there may be potential difficulties in mounting a large randomised controlled trial for endometriosis to assess Omega-3 PUFA because they are a dietary supplement readily available over the counter and already used by women with endometriosis. We have therefore designed this pilot study to assess practical feasibility and following the 'Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials' recommendations for the design of chronic pain trials. TRIAL REGISTRATION: ISRCTN44202346.