title: Determining minimal clinically important differences in Japanese cedar/cypress pollinosis patients.
abstract: BACKGROUND
  Statistically significant results of medical intervention trials are not always clinically meaningful. We sought to estimate the minimal clinically important difference (MCID) (the smallest change in a given endpoint that is meaningful to a patient) during seasonal alteration of Japanese cedar/cypress pollinosis (JCCP).
  
  
  METHODS
  Results of a double-blinded, placebo-controlled trial of JCCP patients conducted between 2008 and 2010 were analyzed using an anchor-based method in which a face scale for Japanese rhinoconjunctivitis quality-of-life questionnaire (JRQLQ) was set as an anchor. MICDs were calculated as changes of average scores, including those for naso-ocular symptoms with 5 items in diary cards (T5SS), naso-ocular symptoms with 6 items (T6SS) and QOL with 17 items on the JRQLQ when face scale scores either improved or deteriorated by one point.
  
  
  RESULTS
  In 2009 and 2010, 3,698 and 374, respectively, grains/cm(2) of pollens were dispersed. The MCIDs for T5SS in 2009 and 2010 were 1.426 (0.285 per item) and 1.441 (0.288), respectively. The MCIDs for T6SS were 4.115 (0.686) and 3.183 (0.531) in 2009 and 2010, respectively. The MCIDs for QOL were 10.469 (0.616) and 6.026 (0.354) in 2009 and 2010, respectively.
  
  
  CONCLUSIONS
  For T5SS in the diary, T6SS and QOL in JRQLQ, unit differences of 1.5 (0.3 per item), 3.6 (0.6) and 8.2 (0.5), respectively, were considered clinically meaningful by JCCP patients. The MCID for symptoms recorded in the diary was stable irrespective of the dispersed pollen level.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Takaya
authors.initials: T
authors.lastname: Higaki
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Okano
authors.forename: Shin
authors.initials: S
authors.lastname: Kariya
authors.forename: Tazuko
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Takenori
authors.initials: T
authors.lastname: Haruna
authors.forename: Haruka
authors.initials: H
authors.lastname: Hirai
authors.forename: Aya
authors.initials: A
authors.lastname: Murai
authors.forename: Minoru
authors.initials: M
authors.lastname: Gotoh
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Okubo
authors.forename: Shuji
authors.initials: S
authors.lastname: Yonekura
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nishizaki
mesh_terms: D000328:Adult; D000368:Aged; D000485:Allergens / Q000276:immunology; D032485:Cryptomeria / Q000009:adverse effects*; D029781:Cupressus / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011058:Pollen / Q000009:adverse effects / Q000276:immunology; D011788:Quality of Life; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology / Q000628:therapy*; D057566:Self Report; D063729:Sublingual Immunotherapy; D055815:Young Adult
chemical_list: D000485:Allergens