Measuring health-related quality of life in women with endometriosis: comparing the clinimetric properties of the Endometriosis Health Profile-5 (EHP-5) and the EuroQol-5D (EQ-5D)

STUDY QUESTION Which of the Endometriosis Health Profile-5 (EHP-5) and the EuroQol-5D (EQ-5D) is the most efficient to assess quality of life in women suffering from endometriosis? SUMMARY ANSWER Although EHP-5 and EQ-5D instruments had an excellent responsiveness, EHP-5 has a better discriminative ability than EQ-5 to measure health-related quality of life (HrQoL). WHAT IS KNOWN ALREADY Proper measurement of HrQoL is important in endometriosis. While many quality of life instruments are available, few have been completely validated in endometriosis. The EHP-5 and the EQ-5D are short and practical scales, which may be useful. Literature is lacking to determine which one is the most suitable in clinical practice or in clinical research. STUDY DESIGN, SIZE, DURATION This prospective and observational study conducted between 1 January 2012 and 31 December 2013 included a total of 253 consecutive women with proven endometriosis, undergoing medical or surgical treatment, in 2 French tertiary care centers. PARTICIPANTS/MATERIALS, SETTINGS, METHODS Women over 18 years consulting for painful symptoms of at least 3 months' duration or for infertility, with endometriosis proven histologically or radiologically, were requested to fill in the 2 scales before (T0) and 12 months after treatment (T1). Construct validity consisted in testing presupposed relationships between the scales and the characteristics of the patients or the endometriosis. Responsiveness to change was calculated for all patients and in each treatment group. Effect sizes were used according to Cohen's d method. MAIN RESULTS AND THE ROLE OF CHANCE A total of 216 women filled in completely all the questionnaires at T0 and 133 (61.6%) at T1. EHP-5 and EQ-5D had good discriminative abilities regarding the patients' symptoms, with significant superiority of EHP-5 concerning three of the nine hypotheses. The largest difference was that calculated for the 'intensity of dysmenorrhea' using the Visual Analogic Scale, with respectively effect size from Cohen's d (ES) = 0.86 95% CI (0.54-1.17) for EHP-5 versus 0.48 95% CI (0.16-0.79) for EQ-5D. There were no differences in EHP-5 or in EQ-5D scores between subgroups according to the characteristics of endometriosis. Overall responsiveness was excellent and equivalent for EHP-5 and for EQ-5D, with, respectively, ES = 0.81 95% CI (0.56-1.56) versus ES = 0.95 95% CI (0.68-1.20). In subgroup analyses, EHP-5 was responsive in case of medical treatment with ES = 0.93 95% CI (0.07-1.70), whereas EQ-5D was not, ES = 0.73 95% CI (-0.06-1.47). LIMITATIONS, REASONS FOR CAUTION Our study population included patients with symptomatic and mainly severe forms of endometriosis, which may suggest a spectrum bias. The evaluation of responsiveness in case of medical treatment was based on a small number of patients, which limits the interpretation of the difference found between the two scales in this subgroup. WIDER IMPLICATIONS OF THE FINDINGS EHP-5 is a simple, efficient and valid tool for evaluating quality of life in daily practice and also valuable to provide a primary outcome in clinical studies evaluating treatment efficacy. STUDY FUNDING/COMPETING INTEREST(S) This work was funded by the Direction à la Recherche Clinique et à l'Innovation of Versailles, France. The authors have no conflicts of interest. TRIAL REGISTER NUMBER None.