title: Response to letter by Wu and Guo.
authors.affiliation: Pain Treatment Unit, Doña Mercedes Primary Health Care Centre, Dos Hermanas, Spain Carlos III Health Institute, Network of Research in Health Services in Chronic Diseases (REDISSEC), Madrid, Spain Support Research Unit, Costa del Sol Hospital, Marbella, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Vas
authors.forename: Francisco
authors.initials: F
authors.lastname: Rivas-Ruiz
mesh_terms: D015667:Acupuncture Analgesia / Q000379:methods*; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000628:therapy*; D008297:Male