INTRODUCTION: The minimal clinically important difference (MCID) is the smallest outcome change that has clinical significance. Its use has not been established in the study of myasthenia gravis (MG). METHODS: Patients from a published intravenous immunoglobulin (IVIg) vs. placebo study were studied. One anchor-based and 3 distribution-based techniques were used to identify quantitative myasthenia gravis score (QMGS), repetitive nerve stimulation (RNS), and single-fiber electromyography (SFEMG) MCID cut-offs. Patients with a change-score exceeding MCID cut-offs were compared. RESULTS: MCID cut-offs were below a QMGS change of 3.0. Anchor-based and 1 × SEM cut-offs showed 58.3% vs. 30.7% responders (P = 0.017), ½ SD 54.2% vs. 19.2% responders (P = 0.018), and effect size 0.519 vs. 0.164 (P = 0.011) in IVIg vs. placebo. Anchor-based (P = 0.73) and effect-size (P = 0.41) MCID cut-offs did not show a difference between IVIg and placebo. MCID methods did not produce meaningful RNS cut-offs. CONCLUSIONS: QMGS MCID values provide clinically relevant information and are recommended in MG trials. MCID analysis shows that improvement in MG patients treated with IVIg reflects clinically meaningful changes.
RCT Entities:
INTRODUCTION: The minimal clinically important difference (MCID) is the smallest outcome change that has clinical significance. Its use has not been established in the study of myasthenia gravis (MG). METHODS:Patients from a published intravenous immunoglobulin (IVIg) vs. placebo study were studied. One anchor-based and 3 distribution-based techniques were used to identify quantitative myasthenia gravis score (QMGS), repetitive nerve stimulation (RNS), and single-fiber electromyography (SFEMG) MCID cut-offs. Patients with a change-score exceeding MCID cut-offs were compared. RESULTS: MCID cut-offs were below a QMGS change of 3.0. Anchor-based and 1 × SEM cut-offs showed 58.3% vs. 30.7% responders (P = 0.017), ½ SD 54.2% vs. 19.2% responders (P = 0.018), and effect size 0.519 vs. 0.164 (P = 0.011) in IVIg vs. placebo. Anchor-based (P = 0.73) and effect-size (P = 0.41) MCID cut-offs did not show a difference between IVIg and placebo. MCID methods did not produce meaningful RNS cut-offs. CONCLUSIONS: QMGS MCID values provide clinically relevant information and are recommended in MG trials. MCID analysis shows that improvement in MGpatients treated with IVIg reflects clinically meaningful changes.
Authors: Bas C Stunnenberg; Willem Woertman; Joost Raaphorst; Jeffrey M Statland; Robert C Griggs; Janneke Timmermans; Christiaan G Saris; Bas J Schouwenberg; Hans M Groenewoud; Dick F Stegeman; Baziel G M van Engelen; Gea Drost; Gert Jan van der Wilt Journal: BMC Neurol Date: 2015-03-25 Impact factor: 2.474
Authors: Srikanth Muppidi; Kimiaki Utsugisawa; Michael Benatar; Hiroyuki Murai; Richard J Barohn; Isabel Illa; Saiju Jacob; John Vissing; Ted M Burns; John T Kissel; Richard J Nowak; Henning Andersen; Carlos Casasnovas; Jan L de Bleecker; Tuan H Vu; Renato Mantegazza; Fanny L O'Brien; Jing Jing Wang; Kenji P Fujita; James F Howard Journal: Muscle Nerve Date: 2019-03-08 Impact factor: 3.217
Authors: James F Howard; Chafic Karam; Marcus Yountz; Fanny L O'Brien; Tahseen Mozaffar Journal: Ann Clin Transl Neurol Date: 2021-05-27 Impact factor: 4.511