Development and Validation of the Endometriosis Health Profile-30 Traditional Chinese (Hong Kong) Version in Endometriosis and Adenomyosis

Endometriosis is a chronic condition caused by the presence of ectopic endometrial tissue outside the uterus, affecting the fallopian tubes, ovaries, pelvic peritoneum or even the urinary and gastrointestinal tracts. Adenomyosis is characterized by the presence of ectopic endometrial gland and stroma in the myometrium with associated myometrial hypertrophy and hyperplasia. Adenomyosis has been reported to occur in 30-60% of the hysterectomy specimen.Endometriosis causes painful symptoms including dysmenorrhoea, pelvic pain, dyspareunia and infertility. Adenomyosis also causes clinically significant symptoms include dysmenorrhoea, pelvic pain and heavy menstrual flow.

Both conditions can impact on the quality of life including the physical, psychological and social aspects. It is important to include quality of life measurements in evaluating the disease severity and response to any given treatment. The 30-item Endometriosis Health Profile (EHP-30), derived from in-depth interviews of patients with endometriosis, is currently the most reliable questionnaire for health-related quality of life measurement in women with endometriosis. It includes specific questions addressing the problems faced by patients with endometriosis. It also exhibits good reliability, validity and interpretability.

The EHP-30 has recently been translated into simplified Chinese version and evaluated with psychometric tests which showed the simplified Chinese version is a valid, reliable and acceptable tool for the measurement of the health-related quality of life of women with endometriosis in mainland China. Unfortunately, this widely accepted tool does not have a traditional Chinese version for the measurement of health-related quality of life of endometriosis in Hong Kong. Furthermore, adenomyosis and endometriosis share similar histological and clinical symptomatology, but application of EHP-30 to adenomyosis has not been studied. The aims of the present study are to translate the EHP-30 English version into traditional Chinese version and to evaluate its psychometric properties in endometriosis and adenomyosis.

EHP-30 consists of 30 items in English, grouping into five subscales measuring pain (11 items), control and powerlessness (6 items), emotions (6 items), social support (4 items) and self-image (3 items) in part one. Part two consists of 23 items, grouping into six subscales may not be applicable to all adenomyosis patients: work (5 items), relationship with children (2 items), sexual intercourse (5 items), medical profession (4 items), treatment (3 items) and infertility (4 items). Participants choose their response from a five point likert scale from 0 to 4. Items within each subscale will be added up to generate a subscale score. Then, the subscale score is divided by maximum possible score and multiply by 100 to give a health status score which 100 represent worst health and 0 represent best health status.

Firstly, approval to use EHP-30 will be obtained from the original author, Dr Georgina Jones. We will adhere to the Good Practice for the Translation and Cultural adaptation process for patient-reported outcomes measures guideline. 6 The EHP-30 will be evaluated by 2 bilingual researchers in the fields of gynaecology independently and decide if any item will be regarded as inappropriate. They will then perform the forward translation of the EHP-30 to traditional Chinese independently. After that, they will review the two versions of translation and hold a meeting for discussion on items of discrepancy, in order to produce one version. Back-translation will be performed by another 2 persons who are professional in Chinese-English translation, after the iterative evaluation of forward translation process. The original and back-translated versions will be compared for accuracy and comprehension by another two monolingual researchers. If substantial differences existed between the two original and the back-translated versions, the translation-back translation process are repeated until a questionnaire representative of the original is obtained. Finally, the back-translated version will be sent to Dr Georgina Jones and the colleagues. Comments on the back-translated version will be obtained from them.