Difference of fibromyalgia symptom scale between the Japanese version of the 2010 ACR preliminary diagnostic criteria for fibromyalgia and the modification of the ACR preliminary diagnostic criteria for fibromyalgia

Dear Sirs, Usui et al. [1] have reported the Japanese version of the 2010 American College of Rheumatology preliminary diagnostic criteria for fibromyalgia (2010-J criteria) based on the 2010 American College of Rheumatology preliminary diagnostic criteria for fibromyalgia (2010 criteria). In the 2010-J criteria, the best cutoff score was 10, while in a previous study (modified 2010 criteria) [2] it was found to be 13. In the modified 2010 criteria, Wolfe et al. [2] created a fibromyalgia symptom scale (FS) of 0–31. In the modified 2010 criteria, the FS arguably consists of a widespread pain index (WPI) of 0–19, a fatigue score of 0–3, a waking unrefreshed score of 0–3, and a cognitive symptoms score of 0–3, as well as a number of the following symptoms (headache, abdominal pain, and depression). However, in the 2010-J criteria, the FS consists of a WPI of 0–19 and a fatigue score of 0–3, a waking unrefreshed score of 0–3, and a cognitive symptoms score of 0–3, as well as the extent (severity) of somatic symptoms in general (such as muscle pain, irritable bowel syndrome, and fatigue/tiredness) [1]. Therefore, the FS of the 2010-J criteria is different from the FS of the modified 2010 criteria. I am afraid that it is very difficult to compare the cutoff score between the 2010-J criteria and the modified 2010 criteria. If Usui et al. would like to compare the cutoff score between the 2010-J criteria and the modified 2010 criteria, they should compare the same FS. Wolfe et al. [3] reported a modification of the 2010 American College of Rheumatology preliminary diagnostic criteria for fibromyalgia in 2011 (2011 criteria). In the 2011 criteria, the FS consists of a WPI of 0–19 and a fatigue score of 0–3, a waking unrefreshed score of 0–3, and a cognitive symptoms score of 0–3, as well as a number of the following symptoms (headaches, pain or cramps in lower abdomen, and depression) [3]. Fortunately, Usui et al. have data about the extent (severity) of somatic symptoms in general. The somatic symptoms include headache, pain/cramps in the abdomen, and depression. They could determine an FS that would be nearly identical to the FS of the 2011 criteria. They could then compare cutoff scores between the 2010-J criteria and the 2011 criteria. If possible, could Usui et al. compare the cutoff scores between the 2010-J criteria and the 2011 criteria?