今日の論文

• van Roon, et al, "Leflunomide in the treatment of rheumatoid arthritis. An analysis of predictors for treatment continuation"
  • id:Fumi:20050830:p4
  • 結論．

Concomitant systemic corticosteroid use, erythrocyte sedimentation rate at the start of treatment and attending rheumatologist were found to be predictive for leflunomide survivai.

• • "Attending rheumatologist" という要因がよくわからない．それって，固定効果か？

The rheumatologist with the median number of included patients was used as the reference rheumatologist for calculating maximal contrasts within the group of attending rheumatologists in this study.

The influence of the attending rheumatologist seems to be a major contributor to leflunomide survival, compared with the other variables found to be associated with leflunomide survival.

• • MTX の同様の研究でも attending rheumatologist は predictor になったらしい．Hoekstra, et al (2003), J Rheumatol, "Longterm observational study of methotrexate use in a Dutch cohort of 1022 patients with rheumatoid arthritis" 要旨しか見ていない．
• Benson & Hartz (2000) NEJM, "A comparison of observational studies and randomized, controlled trials"
  • 観察研究 (observational study) は RCT に比べて効果が強く出る傾向がある，と言われている（きた）．専門家達はこうも言ってきた．

observational studies should not be used for defining evidence based medical care: "If you find that [a] study was not randomized, we'd suggest that you stop reading it and go on to the next article."

• • これはこれで，今となっては行き過ぎた「エビデンス依存症」．
  • 以前に比べれば，方法論も進歩してきた．統計解析法も然り．1985-1998 年の研究を survey した．

We found that little evidence that estimates of treatment effects in observational studies reported after 1984 are either consistently larger than or qualitatively different from those obtained in randomized, controlled trials.

• • 観察研究だって "do provide valid information" なのだ．
  • 結論をこう締めくくる．

Only with a greater willingness to analyze these data bases is it possible to achieve a realistic understanding of how observational studies can best be used.

• Greenblatt, et al, "Pharmocokinetics and pharmacodynamics of single-dose triazolam: electroencephalography compared with the Digit-Symbol Substitution Test"
  • id:Fumi:20050826:p3
  • 薬物血中濃度の AUC と，EEG もしくは DSST の効果曲線の 'AUC' のばらつきを比較すると．．．

the between-subject coefficient of vriation for plasma AUC (standard deviation 28% of the mean) was much less than the coefficient of variation for placebo-normalized values of AUC_effect for DSST (89%) or EEG (95%).
The results of this study indicate that between-subject variability in triazolam kinetics is exceeded by variability in response.