title: Systematic review of endometriosis pain assessment: how to choose a scale?
abstract: BACKGROUND
  Numerous studies concerning endometriosis and pain have been reported. However, there is no consensus on the best method to evaluate pain in endometriosis and many scales have been used. Moreover, there are only a few descriptions of minimal clinically important differences after treatment (MCID) to evaluate variations in pain. In our study, we aim to identify pain scales used in endometriosis pain treatment, to address their strong and weak points and to define which would be the ideal scale to help clinicians and researchers to evaluate endometriosis-related pain.
  
  
  METHODS
  A search of the MEDLINE and EMBASE databases was carried out for publications in English, French or Portuguese from 1980 to December 2012, for the words: endometriosis, treatment, pain. Studies were selected if they studied an endometriosis treatment and a pain scale was specified. A quantitative and a qualitative analysis of each scale was performed to define strong and weak points of each scale (systematic registration number: CRD42013005336).
  
  
  RESULTS
  A total of 736 publications were identified. After excluding duplications and applying inclusion criteria 258 studies remained. We found that the visual analog scale (VAS) is the most frequently used scale. Both VAS and the numerical rating scale (NRS) show a good balance between strong and weak points in comparison with others such as the Biberoglu and Behrman scale. Concerning MCID, only VAS, NRS and Brief Pain Inventory scales have reported MCID and, among these, only VAS MCID has been studied in endometriosis patients (VAS MCID = 10 mm). Adding the Clinical Global Impression score (CGI) to the pain scale allows calculation of the MCID.
  
  
  CONCLUSIONS
  When using pain scales their strengths and weaknesses must be known and included in the analysis. VAS is the most frequently used pain scale and, together with NRS, seems the best adapted for endometriosis pain measurement. The use of VAS or NRS for each type of typical pain related to endometriosis (dysmenorrhea, deep dyspareunia and non-menstrual chronic pelvic pain), combined with the CGI and a quality-of-life scale will provide both clinicians and researchers with tools to evaluate treatment response.
authors.affiliation: Department of Gynecologic Surgery, CHU Estaing Clermont Ferrand, 63058 Clermont Ferrand Cedex 1, France Faculté de medicine, ISIT - Université d'Auvergne, Place Henri Dunant, 63000 Clermont-Ferrand, France nicolas.bourdel@gmail.com.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bourdel
authors.affiliation: Department of Gynecologic Surgery, CHU Estaing Clermont Ferrand, 63058 Clermont Ferrand Cedex 1, France.
authors.forename: João
authors.initials: J
authors.lastname: Alves
authors.affiliation: Centre de Pharmacologie Clinique, CHU Clermont Ferrand, Inserm CIC 501, Inserm, U1107 Neuro-Dol, F-63003 Clermont-Ferrand, France.
authors.forename: Gisele
authors.initials: G
authors.lastname: Pickering
authors.affiliation: Department of Gynecologic Surgery, CHU Estaing Clermont Ferrand, 63058 Clermont Ferrand Cedex 1, France.
authors.forename: Irina
authors.initials: I
authors.lastname: Ramilo
authors.affiliation: Department of Gynecology and Obstetrics, Rouen University Hospital-Charles Nicolle, 1 rue de Germont, 76031 Rouen, France.
authors.forename: Horace
authors.initials: H
authors.lastname: Roman
authors.affiliation: Department of Gynecologic Surgery, CHU Estaing Clermont Ferrand, 63058 Clermont Ferrand Cedex 1, France Faculté de medicine, ISIT - Université d'Auvergne, Place Henri Dunant, 63000 Clermont-Ferrand, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Canis
mesh_terms: D004412:Dysmenorrhea / Q000453:epidemiology; D004414:Dyspareunia / Q000453:epidemiology; D004715:Endometriosis / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D010147:Pain Measurement / Q000379:methods*; D017699:Pelvic Pain / Q000188:drug therapy; D011788:Quality of Life
keywords: endometriosis; pain; responder; review; scale