Determining minimal clinically important differences in Japanese cedar/cypress pollinosis patients

Takaya Higaki, Mitsuhiro Okano, Shin Kariya, Tazuko Fujiwara, Takenori Haruna, Haruka Hirai, Aya Murai, Minoru Gotoh, Kimihiro Okubo, Shuji Yonekura, Yoshitaka Okamoto, Kazunori Nishizaki

Research output: Contribution to journalArticle

5 Citations (Scopus)

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/cm2 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.

Original languageEnglish
Pages (from-to)487-493
Number of pages7
JournalAllergology International
Volume62
Issue number4
DOIs
Publication statusPublished - 2013

Keywords

  • Face scale
  • Minimal clinically important difference
  • Pollinosis
  • Quality of life
  • Symptom score

ASJC Scopus subject areas

  • Immunology and Allergy

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