今日の論文

• Galetin, Ito K, Hallifax, and Houston B (2005) JPET, "CYP3A4 Substrate Selection and Substitution in the Prediction of Potential Drug-Drug Interactions"
• van Roon, et al, "Leflunomide in the treatment of rheumatoid arthritis. An analysis of predictors for treatment continuation"
  • id:Fumi:20050826:p3
  • 観察研究．患者 279 人のうち，173 人 (62%) がレフルノミド治療から脱落した．脱落に関するリスク（ハザード）を解析したというわけ．
  • Introduction が熱い．いきなりこう始まる．レフルノミドがどうこう，はほとんど述べられない．

The view that randomized controlled trials are the 'gold standard' for evaluation and that observational methods have little additional value is widely accepted. (...) However, results from a study comparing the results of observational and randomized, controlled stuidies in 19 different fields of medicine suggest that observational studies usually do provide valid additional information*1.
(...)
One of the major reasons to conduct observational studies is the potentially limited external validity of the results of the randomized controlled trial. (...) For example, healthcare providers in the setting of clinical trials may be unrepresentative, e.g. because they are innovators. (...) Furthermore, the treatment in the trial may be atypical.  For example, patients included in trials may receive different care due to intensified follow-up.

• • 'Channelling bias' というものがあって，

when a new drug comes onto the market, a large pool of subjects with insufficient response or adverse drug reactions on existing medications is present.  These patients will be prone to be treated with the new medication and thereby introduce a bias in the population treated with that medication and the treatment outcomes.  Therefore, channelling bias has to be taken into account when extrapolating the results from randomized controlled trials to the setting of care-as-usual.

• • だから，今回は care-as-usual での観察研究を実施したのだ！

*1:Benson & Hartz, 2000, NEJM, "A comparison of observational studies and randomized, controlled trials"