よって、今回の“Duration of relapses”の差からは、著者らの計算方法の方が、従来の計算方法よりも年間再発率に差が出やすい(250ug投与群に有効性を見出しやすい)と言えるかと思います。しかしこの状態で計算した年間再発率でも、50ug投与群と250ug投与群との差は、片側検定という手段を選択してもp=0.047で、スレスレの有意差となっています。従来の計算方法での数値は記載されていないので想像に過ぎませんが、従来の計算方法では有意差が出ないのではないかなと邪推してしまいます。
Patients with OS-MS and C-MS were also analyzed as separate subgroups. The number of OS-MS cases was 18 (19.4%) in the 50 µg group and 22 (23.2%) in the 250 µg group. Relapses in patients with OS-MS involved the spinal cord or optic nerves only, with two exceptions: one involving the cerebrum and cerebellum in one patient in the 50 µg group, and another involving the brainstem in one patient in the 250 µg group.
The ratio of the annual relapse rate in the 250 µg group to that in the 50 µg group was 0.608 (–39.2%) in the OS-MS patients and 0.746 (–25.4%) in the C-MS patients, i.e., showing comparable treatment effects of IFNB-1b in patients with OS-MS and C-MS (p = 0.093 in OS-MS and p = 0.106 in C-MS, see figure 2).
The proportion of relapse-free patients was 28% (5/18) in the 50 µg group and 27% (6/22) in the 250 µg group in patients with OS-MS (p = 0.653), compared to 36% (27/75) in the 50 µg group and 49% (36/73) in the 250 µg group in patients with C-MS (p = 0.067).
There were 50 patients in the 50 µg group and 43 patients in the 250 µg group with a diagnosis of C-MS, and lesions involving the spinal cord prior to the start of the study. Of these, 29 (58%) in the 50 µg group and 18 (42%) in the 250 µg group had relapses involving the spinal cord during the study, compared with 13/18 (72%) in the 50 µg group and 12/22 (55%) in the 250 µg group for patients diagnosed with OS-MS. Of the remaining C-MS patients, i.e., those with no lesions involving the spinal cord prior to study entry, 3/25 (12%) in the 50 µg group and 3/30 (10%) in the 250 µg group experienced relapses involving the spinal cord. The ratio of the annual relapse rate between the 250 µg and 50 µg treatment groups in patients with spinal cord lesions was 0.542 in patients with OS-MS and 0.571 in patients with C-MS, demonstrating a comparable reduction in relapses involving the spinal cord in both patient groups (figure 3).
あと、余談ですが言い訳を。Editorialについて、Xさんの訳と小生の訳の差は“should be reluctant”の訳し方の差にあると思います。ここを訳す時、実はうーん、と唸ってました。
というのは、前段で“could be due to inadequate power”と“may mean that interferon beta is effective”とあり、これを“However”で受けて、“should be reluctant”と来ているので、その後の段落(OSMSに限った研究をきちんとするべきだという提言)を考えてもXさんの訳の意かなぁと思ってました。